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1
EFFECTS OF INCLUSION OF OYSTER
MUSHROOM (Pleurotus sajor-caju) ON THE
PHYSICO-CHEMICAL, SENSORY AND
MICROBIAL PROPERTIES OF HAMBURGER
BY
OLONTA, OOBE AGABA
(PG/M.Sc/07/43516)
DEPARTMENT OF FOOD SCIENCE AND
TECHNOLOGY
UNIVERSITY OF NIGERIA, NSUKKA
JULY, 2012
2
TITLE PAGE
EFFECTS OF INCLUSION OF OYSTER MUSHROOM
(Pleurotus sajor-caju) ON THE PHYSICO-CHEMICAL,
SENSORY AND MICROBIAL PROPERTIES OF
HAMBURGER
A DISSERTATION SUBMITTED TO
THE DEPARTMENT OF FOOD SCIENCE AND
TECHNOLOGY UNIVERSITY OF NIGERIA, NSUKKA, IN
PARTIAL FULFILMENT OF THE REQUIREMENTS FOR
THE AWARD OF MASTER OF SCIENCE (M.Sc) DEGREE IN
FOOD SCIENCE AND TECHNOLOGY
BY
OLONTA, OOBE AGABA
(PG/M.Sc/07/43516)
JULY, 2012
3
APPROVAL PAGE
This research has been supervised and approved as having met the
requirements of the partial fulfilment for the award of Master of Science (M.Sc)
degree of the Department of Food Science and Technology, University of
Nigeria, Nsukka.
.................................... ...............................
Prof. Okonkwo, T. M. Mr. Bhandary, C. S.
Supervisor Head of Department
................................... ..............................
Prof. Ugwu, S. O. C. External Examiner
Dean; Faculty of Agriculture
4
CERTIFICATION
This research has been conducted by Olonta, Oobe Agaba
(PG/M.Sc/07/43516) under the supervision of Professor Okonkwo, T. M. This
thesis is the original work of the researcher, and has not been submitted in part
or full for any other Diploma or Degree of this or any other University. It is not
the complete copy of any other work else where, hence no part of it shall be
reproduced, or transmitted in any form or by any means otherwise without prior
permission of the under signed authorities.
......................................
Olonta, Oobe Agaba
Student
...................................... ......................................
Prof. Okonkwo, T. M. Mr. Bhandary, C. S.
Supervisor Head of Department
5
DEDICATION
Dedicated to my children
6
AKNOWLEDGEMENT
I wish to first appreciate God Almighty, for providing me with the
determination and courage to undertake this study. I am very thankful to my
Supervisor (Prof. Okonkwo, T. M.), for his meticulous and articulate
contribution that has resulted in this sound report. I cannot forget to appreciate
all my lecturers in the Department of Food and Science and Technology,
University of Nigeria, Nsukka, for their various contributions to this work. I
wish to specially thank Prof. Ani, J. C. (Mrs.), for her motherly role. A word of
tribute to Prof. Obanu, Z.A. (Blessed memory) has to be registered. I wish to
acknowledge Dr. Mrs. Nwaoha, I. E., Ezeugwu, C. N., Mrs. Omah, E. C., Mrs.
Asogwa, I., and others for their unrelented moral support. My appreciation also
goes to Dr. Onyisi, the Mycologist that helped to identify mushrooms for me, as
well as Obioma U. and her friends (Chinyere and Charity) who have been my
typists all this while. This acknowledgement cannot be complete without words
of appreciation to my course mates. I cannot forget any of you. Finally, I
appreciate my children for standing by me through this programme.
7
TABLE OF CONTENT
Title page - - - - - - - - - - i
Approval page - - - - - - - - - - ii
Certification - - - - - - - - - - iii
Dedication - - - - - - - - - iv
Acknowledgement - - - - - - - - - v
Table of content - - - - - - - - - - vi
List of Tables - - - - - - - - - - x
List of Figures - - - - - - - - - - xi
Abstract - - - - - - - - - - - xii
CHAPTER ONE
1.0 INTRODUCTION - - - - - - - - 1
1.1 Statement of Problems - - - - - - - - 3
1.2 Justification of the Research- - - - - - - 3
1.3 Objectives of the Study - - - - - - - - 4
CHAPTER TWO
2.0 LITERATURE REVIEW - - - - - - - 5
2.1 Nutritional value of mushroom - - - - - - 5
2.2 Nutritional value of meat - - - - - - - 6
2.3 Chemical composition of mushroom - - - - - 7
2.4 Chemical composition of meat - - - - - - - 11
2.5 Problems of meat consumption - - - - - - - 14
2.6 Mushroom health benefits - - - - - - - - 15
2.7Sensory attributes of mushroom - - - - - - - 16
2.8 Physical and sensory qualities of meat - - - - - - 17
2.8.1 Colour - - - - - - - - - - 17
2.8.2 Juiciness - - - - - - - - - - 18
8
2.8.3 Texture/toughness/tenderness - - - - - - - 18
2.8.4 Flavour - - - - - - - - - - 19
2.9 Hamburger Production - - - - - - - - 20
2.9.1 Cut of Beef Used For Hamburger - - - - - 20
2.9.2 Hamburger Composition and Ingredients - - - - 20
3.9.3 Cooking of Hamburger - - - - - - - - 21
2.10 Importance of hamburger - - - - - - - 21
CHAPTER THREE
3.0 MATERIALS AND METHODS - - - - - 22
3.1 Raw Materials and Burger Production - - - - - 22
3.2 Analysis - - - - - - - 23
3.2.1 Proximate Analysis - - - - - - - - 24
3.2.1.1 Moisture Content Determination - - - - - 24
3.2.1.2 Ash Determination - - - - - - - - 24
3.2.1.3 Crude Protein Determination - - - - - - 25
3.2.1.4 Determination of Fat - - - - - - - - 25
3.2.1.5 Determination of Carbohydrates - - - - - - 26
3.2.2 Mineral Element Analysis - - - - - - - 26
3.2.2.1 Determination of Iron - - - - - - - - 26
3.2.2.2 Determination of Magnesium - - - - - - - 26
3.2.2.3 Determination of calcium - - - - - - - 27
3.2.2.4 Determination of Phosphorus - - - - - - - 27
3.2.2.5 Determination of Sodium and Potassium - - - - 28
3.2.2.6 Determination of Zinc - - - - - - - - 28
3.2.3 Analysis of Vitamins - - - - - - - - 29
3.2.3.1 Determination of Thiamin (B1) - - - - - 29
3.2.3.2 Determination of Riboflavin - - - - - - - 30
9
3.2.3.3 Determination of Niacin - - - - - - - 31
3.2.3.4 Determination of Vitamin C - - - - - - - 31
3.2.3.5 Determination of Vitamin A - - - - - - 32
3.2.4 Determination of Protein Solubility - - - - - - 33
3.2.5 Determination of pH - - - - - - - - 33
3.2.6 Determination of Water Activity (aw) - - - - - 33
3.2.7 Microbial Analysis - - - - - - - - 34
3.2.7.1 Total Viable Count Determination - - - - - - 34
3.2.7.2 Coliform Count Determination - - - - - - 34
3.2.7.3 Mould Count Determination - - - - - - - 34
3.2.8 Sensory Analysis - - - - - - - - - 34
3.9 Experimental Design - - - - - - - - 35
CHAPTER FOUR
4.0 RESULTS AND DISCUSSION - - - - - 36
4.1 Contribution of mushroom to the proximate composition of hamburger. 36
4.2 Contribution of mushroom to the mineral element composition
of hamburger - - - - - - - - - 41
4.3 Contribution of mushroom to the vitamin composition of hamburger 54
4.4 Contribution of mushroom to the physical characteristics of hamburger 60
4.5 Contribution of mushroom to the sensory qualities of hamburger. - 63
4.5.1 Colour attributes of hamburger with and without mushroom - 63
4.5.2 Contribution of mushroom to the texture of hamburger - - 65
4.5.3 Contribution of mushroom to the odour/aroma of hamburger - 66
4.5.4 Effect of mushroom inclusion on the taste of hamburger - - 68
4.5.5 Contribution of mushroom to the general acceptability of hamburger 70
4.6 Contribution of mushroom to the quality changes of hamburger
during storage - - - - - - - - - 72
4.6.1 Changes in pH of hamburger samples with and without mushroom
during storage - - - - - - - - - 72
10
4.6.2 Rates of change of pH of burger samples during storage - - 76
4.6.3 Rates of change of pH of burger samples during storage - - 77
4.6.4 Rates of changes of water activities of burger samples during storage 81
4.6.5 Changes in total viable count of burger samples during storage - 82
4.6.6 Contribution of mushroom to the coliform count of hamburger - 83
4.6.7 Changes in mould counts during storage - - - - - 84
CHAPTER FIVE
5.0 CONCLUSION AND RECOMMENDATIONS - - - 86
5.1 Conclusion - - - - - - - - - - 86
5.2 Recommendation - - - - - - - - - 86
REFERENCES
APPENDIX
11
LIST OF TABLES
Table 1: Approximate annual yield of mushroom (Agaricus bisporus),
beef and fish (dry protein, kg/ha). - - - - - 2
Table 2: Proximate analysis of edible mushrooms (% fresh weight basis) 8
Table 3: Proximate composition of the Mushroom (Pleurotus Sp) - 8
Table 4: Essential amino acid composition of proteins of mushroom and egg
(g per 100g of proteins) - - - - - - - 9
Table 5: Composition of cultivated mushrooms and some common
vegetables per 100g (%)- - - - - - - 10
Table 6: Vitamin content of some edible mushrooms
(mg per 100g, dry weight) - - - - - - - 10
Table 7: Mineral element content of some edible mushrooms
(mg per 100g, dry weight) - - - - - - 11
Table 8: Chemical composition of lean meat (%) - - - - 11
Table 9: Chemical composition of lean beef (%) - - - - 12
Table 10: Essential amino acid composition of raw lean meat (g/100g) - 12
Table 11: Mineral content of raw meat (mg/100g) - - - - 13
Table 12: Vitamin content of various meats (per 100g) - - - 13
Table 13: Proximate composition of hamburger samples with and
without mushroom- - - - - - - - 37
Table 14: Mineral element composition of hamburger with and
without mushroom - - - - - - - - 44
Table 15: Effect of mushroom inclusion on the vitamin composition
of hamburger - - - - - - - - 54
Table 16: Effect of mushroom inclusion on the physical characteristics
of hamburger - - - - - - - - - 61
Table 17: Effect of mushroom addition on the colour of hamburger - 64
Table 18: Effect of mushroom addition on texture of hamburger - - 66
Table 19: Effect of mushroom addition on the aroma/odour of hamburger 67
Table 20: Taste of hamburger with and without mushroom - - 69
Table 21: General acceptability of hamburger with and without mushroom 71
12
Table 22: Rates of change of burger samples during storage - - 76
Table 23: Rates of changes of water activities of burger samples during
storage. - - - - - - - - - - 81
Table 24: Changes in TVC of burger samples during storage - - - 82
Table 25: Changes in coliform counts of burger samples during storage 84
Table 26: Mould counts of burger samples with and without mushroom 85
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LIST OF FIGURES
Figure 1: Flow chart for the preparation of burger - - - - 23
Figure 2; Changes in pH during storage (Ribeye muscle samples) - 73
Figure 3: Changes in pH during storage (muscle of round samples) - 74
Figure4: Changes in pH during storage (chuck muscle samples) - - 75
Figure5: Changes in water activity during storage (Ribeye muscle samples) 78
Figure6: Changes in water activity during storage (Muscle of round samples) 79
Figure7: Changes in water activity during storage (chuck muscle samples) 80
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ABSTRACT
This research was conducted to determine the contribution of mushroom
on the physico-chemical, nutritive and sensory properties of hamburger. Four
burger samples were prepared with different combinations (0%, 20%, 40% and
60%) of mushroom. The inclusion of mushroom caused a general decrease in
the protein, fat, moisture, ash, mineral element, vitamin as well as soluble
protein and an increase in the carbohydrate contents of hamburgers. The
proximate and soluble protein contents of burgers without (0%) mushroom
differed significantly (P < 0.05) from burgers with mushroom. Significant
differences (P < 0.05) in the mineral element (Magnesium, iron, phosphorus,
zinc, calcium and sodium) content were observed between burgers without (0%)
mushroom and burgers with mushroom. The change in the potassium content of
all the burger samples did not show any significant difference (P > 0.05).
Burgers without mushroom differed significantly (P < 0.05) from those with
mushroom in their vitamin C, A, thiamin and riboflavin content, while no
significant difference (P > 0.05) was observed for niacin content among all the
burger samples. The burgers with mushroom were found to still make
appreciable contribution to the daily values (DV) of most of the nutrients in one
serving size of 100g. The pH and water activity (aw) of the burgers ranged
between 5.40 - 5.65 and 0.84-0.96 respectively. The degree of “likeness” of the
organoleptic qualities and general acceptability was rated highest for burgers
without mushroom, and reduced gradually with progressive inclusion of
mushroom. The least-rating (“slightly dislike”) was observed in the taste of
ribeye and chuck muscle burgers with more than 20% mushroom. Chuck
muscle burgers were most prefered to burgers from other muscle cuts. The
microbial counts (TVC, mould and coliform counts) for burgers at the end of 8
days storage under ambient condition showed that significant differences (P <
0.05) existed among muscle at the various levels of mushroom. No specific
trend could be established to account for the addition of mushroom on the
microbial activities of hamburger during storage. Coliform and mould counts
were generally lower than TVC throughout the storage period. No physical sign
of spoilage was observed at the end of eight days of storage.
15
CHAPTER ONE
1.0 INTRODUCTION
Meat is the flesh or muscular tissue of animals (Fox and Cameron, 1977).
Similarly, Forrest et al, (1975) defined meat as the flesh of animals which is
suitable for use as food. Although meat eating remains at a high level, there
have been distinct changes in the type of meat eaten (Varnam and Sutherland,
1995). The most striking is the rise in consumption of poultry and sea food and
less red meat (Kinsman, 1994). It was further emphasized that the success of
fast-food outlets means that increasing quantities of beef and, to a lesser extent,
other meats are eaten as burgers and similar products. Still according to
Kinsman (1994), meat is the preferred food eaten at home.
Mushroom is the fleshy, spore bearing fruiting body of a fungus, typically
produced above ground on soil or on its food source (Moore, 2003). Mushroom
is more of common application to macroscopic fungi fruiting bodies than one
having precise taxonomic meaning (Chang and Miles, 2004). However,
according to Bahl (2000), mushroom is a general term applied to the fruiting
bodies of the fleshy fungi and as such belongs to different groups of fungi. The
majority of mushrooms belong to Hymenomycetes (Basidiomycotina) while
others belong to Discomycetes (Ascomycotina).
How long man has been eating mushrooms is, of course, impossible to
determine, but one can speculate with reasonable assurance that such fungi have
periodically been a part of his diet for many centuries (Gray, 1970). It was
further stressed that until recent times in the United States, mushrooms were
used primarily as a condiment to garnish steaks. With the development and
expansion of the mushroom canning industry however, they appear to be
gaining favour as a base for soup and as ingredient in many dishes in which
they were formerly seldom used. Bano et al (1963) reported that mushrooms
represent one of the world’s greatest untapped resources of nutritious and
palatable foods.
16
Some mushrooms are edible while others are poisonous (Bahl, 2000).
Edible mushrooms are distinctive in some ways. Once their distinguishing
features are learned, they cannot be confused with any dangerously poisonous
species.
Mushroom is being cultivated in many parts of the world presently.
Commercial mushroom growing was first initiated in India (Bahl, 2000).
Mushrooms have the capacity to convert nutritionally valueless substances into
high protein food. It was stressed further (Bahl, 2000) that on an area basis they
are a more valuable source of protein (Table 1). Besides being a food article,
mushrooms are variously exploited by man (Bahl, 2000).
Table 1: Approximate annual yield of mushroom (Agaricus bisporus), beef
and fish (dry protein, kg/ha).
Protein source yield
Beef, cattle by conventional Agriculture 78
Fish, intensive pond rearing 675
Agaricus bisporus 65, 000
Source: Bahl (2000)
Hamburger: A Ground Meat Product
According to Wikipedia (2008), ground beef, beef mince or hamburger
meat (in North America) or minced meat (in the rest of the English world) is a
ground meat product made of beef finely chopped by a meat grinder. Burgers
are usually made from ground meat or meat substitute, then reshaped to form
patties and cooked and eaten (Uncyclopedia, 2008). Burgers made with beef are
traditionally known as hamburgers, though due to the profusion of burger types
over the last few decades are also called beef burgers. Uncyclopedia (2008)
further emphasized that other meats such as venison, bison, pork, chicken,
turkey, and fish can be used. The name generally changes accordingly with the
17
name of the burger prefixed by that of the meat source. For example turkey
burger, buffalo burger, jersey burger, vegiburger, etc. Burgers not made from
beef are often marketed as more exotic than hamburger or as being healthier
than beef patties. In the UK, the word burger often refers to the filling of a
burger sandwich (that is what in USA would be termed a patty).
1.1 Statement of Problem
Though, meat is a versatile item of the diet, several reports have indicted
meat in respect of a host of human health problems, which are not commonly
found with plant foods. There is too much dependence on the use/consumption
of meat, especially red meat in the diet, with a consequent high cost. Meat is an
ideal nutritious food. In many communities it is eaten to confer prestige and
class distinction. Many plant materials cannot form satisfactory total
replacement for meat, nor achieve compatible and acceptable combination with
meat as a product to enable reduction of meat intake, yet meeting the nutritional
requirements of humans. The role of meat in the diet is so unique that it cannot
be completely removed from the diet.
Mushrooms are valuable sources of high quality cheap food, which have
been denied attention, especially in Nigeria and hence not utilized in the diet.
The nutritional attributes of mushrooms as well as the physical and sensory
qualities are such that mushrooms could combine well with meat to produce a
novel nutritious and acceptable product.
1.2 Justification of the Research
Effective combination of meat and mushroom would enhance the
utilization of mushrooms in the diet and subsequent need for the cultivation of
mushrooms. The meat/mushroom combination should reduce the ultimate
intake of meat and minimize the various acknowledged health problems of meat
intake. Most of the health benefits derivable from mushrooms are counter
effective against the problems of meat consumption. The nutritional values of
mushroom and meat are similar; hence partial replacement of meat with
18
mushroom will not cause any significant reduction in the nutritional value of the
new product. Mushroom has a property like meat; hence it is expected to form a
compatible and acceptable combination with meat without loss of the physical
and sensory qualities of meat.
1.3 Objectives of the Study
The broad objective of this research is to ascertain the contribution of
mushroom to the physico-chemical, nutritive and sensory properties of
hamburger, when the meat is partially replaced with mushroom.
Specific objectives would include;
- To determine the effect of mushroom partial replacements on the
physico-chemical properties of hamburger.
- To evaluate the contribution of mushroom to the sensory properties and
general acceptability of hamburger.
- To evaluate the effect of mushroom partial replacement on the nutritive
qualities of hamburger.
- To evaluate the shelf-stability of the mushroom-beef burger.
19
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 Nutritional Value of Mushroom
Mushrooms are highly nutritious, contrary to popular belief. According to
USDA (2006), often grouped with vegetables, mushrooms provide many of the
attributes of produce as well as attribute more commonly found in meat, beans
and grains. It was further stressed that the nutrients present in mushroom are
considered to be typical of meat. The food value of mushroom is considered
(Bahl, 2000) to lie between meat and vegetables. It was further emphasized that,
mushrooms have been proved by experiments to be well suited to supplement
diets which lack protein and in this sense; they have rightly been called
“vegetable meat”.
Mushrooms supply proteins, amino acids, B group vitamins, vitamin C,
K, mineral elements such as copper, magnesium, phosphorus, potassium,
selenium and iron (Gray, 1970; Bahl, 2000 and Moore, 2003). It was further
reported that mushrooms are among the few food sources rich in the trace
element germanium, which is thought to promote efficient use of oxygen in the
body and protect against damage from free radicals. Some species of
mushrooms even provide β-carotene, a powerful antioxidant.
Among the vitamins reportedly found in mushrooms are riboflavin,
thiamin, niacin, biotin, cobalamin, pantothenic acid, vitamin C and K.
Although, they are not significant sources of vitamin D, some mushrooms can
become significant sources after exposure to ultra violet light. This also darkens
their skin (MSNBC, 2006).
Mushrooms are low in calories (Moore, 2003; USFDA, 2005; USDA,
2006). In view of their low calories, they are considered as the number one diet
to be recommended to weight watchers and heart patients (Bahl, 2000) as the
ideal food to lose weight and maintain a healthy heart (Moore, 2003).
20
According to Bano et al (1963), mushrooms, as compared with fruits and
vegetables, are a better source of proteins, containing lysine, arginine, histidine,
and threonine in high concentrations. All the essential amino acids required by
an adult are present in mushrooms (Hayes and Haddad, 1976). Tryptophan and
Lysine are reported to be present in high concentration as compared with
cystein and methionine. Bahl (2000) reported that, among the many novel
sources of food, particularly of protein, mushrooms apart from being famous for
their appetizing flavour offer themselves as potential protein source to bridge
the protein gap. A study carried out by Mshandete and Cuff (2007) on three
wild edible mushrooms showed a higher protein content than many cereals and
vegetables.
The small amount of fat in mushroom (1-6.6% according to Diez and
Alvarez, 2001; Mshandete and Cuff, 2007) consists mainly of unsaturated fatty
acids (Park, 2001; Moore, 2003). In the study of some wild species of
mushrooms by Hughes (1962), Diez and Alvarez (2001), Leon-Guzman et al
(2007), it was reported that unsaturated fatty acids, particularly oleic and
linoleic acids, predominate in the total free fatty acids. USDA (2006) further
stressed that mushrooms are very low in sodium and are cholesterol free.
The digestibility of mushrooms protein is as high as 72-83% (Lintzel,
1941; Gray 1970). Moore (2003) reported that all mushrooms must be cooked
to take advantage of their nutritional values.
2.2 Nutritional Value of Meat
Meat is a major source of several essential nutrients (Bastin, 2007). Meat
is high in both protein quality and quantity. According to Vernon (1988) and
Bastin (2007), all the essential amino acids are found in meat, making it a
complete protein. Meat is considered, justifiably, a very high quality protein
food with the types and ratio of amino acids being similar to those required for
maintenance and growth of human tissues (Varnam and Sutherland, 1995). It
21
was further stated that the Biological value (Bv) of meat is 0.75. The
digestibility of meat protein, like that of milk and egg is 94-97% compared with
78-88 for plant proteins. According to Vernon (1988), meat is readily digested
and it acts as a stimulant to gastric secretion.
Muscle tissue is generally an excellent source of some of the B complex
vitamins, especially, thiamin, riboflavin, niacin, pyridoxine and cobalamin
(Vernon, 1988; Varnam and Sutherland, 1995; Pearson and Gillet, 1996; Bastin,
2007), and poor in fat soluble vitamins (Pearson and Gillet, 1996).
Lean meat is recognized as a good source of iron and phosphorus, but is
usually low in calcium (Varnam and Sutherland, 1995). Pearson and Gillett
(1996) also reported that meat is a good source of phosphorus, zinc and iron, but
still low in calcium. It was further stated that meat contributes significant
percentages of a number of other minerals, including copper, sodium, potassium
and magnesium. Similarly, Vernon (1988) reported the mineral content of meat
to include iron, copper and phosphorus. Pearson and Gillett (1996) also reported
that meat is not only a source of iron but that it enhances iron absorption from
other sources. According to Bastin (2007), the heme iron is more easily
absorbed by the body than non heme iron. It was stressed further that about 40%
of iron in meat is heme iron.
2.3 Chemical Composition of Mushroom
Proximate analysis of some edible mushrooms (table 2) reported by Gray
(1970) and Bano (1976), showed very little differences.
22
Table 2: Proximate analysis of edible mushrooms (% fresh weight basis)
Mushroom Moisture Ash Protein Fat Crude Fibre
Agaricus bisporus 89.5 1.25 3.94 0.19 1.09
Lepiota Sp 91.0 1.09 3.3 0.18 0.86
Pleurotus Sp 90.0 0.97 2.78 0.65 1.08
Pleurotus ostreatus 92.5 - 2.15 - -
Temitomyces Sp 91.3 0.81 4.1 0.22 1.13
Volvariella displasia 90.4 1.10 3.90 0.25 1.57
Volvariella volvacea 88.4 1.46 4.90 0.74 1.38
Sources: Gray (1970) and Bano (1976).
Bano et al (1963) reported a very similar proximate composition for Pleurotus
Sp (table 3).
Table 3: Proximate composition of the Mushroom (Pleurotus Sp)
Constituent Percent
Moisture 90.95
Ash 0.974
Protein 2.78
Non protein nitrogen 0.14
Fat (ether extract) 0.165
Crude fibre 1.08
Source: Bano et al (1963).
A total of 17 amino acids were quantitatively identified in edible
mushrooms, including all the essential amino acids (table 4).
23
Table 4: Essential amino acid composition of proteins of mushroom and
egg (g per 100g of proteins)
Essential amino acids Mushrooms Egg Proportion*
Arginine 6.7 6.4 1.0
Histidine 2.1 2.1 2.0
Lysine 5.0 7.2 5.0
Tryptophan 0.9 1.5 1.0
Phenylalnine 2.0 6.3 3.5
Methionine 1.26 4.1 3
Threonine 4.2 4.9 2.5
Leucine 4.4 9.2 4.0
Isoleucine 5.8 8.0 2.5
Valine 4.65 7.3 3.5
*Proposed by Rose (1937)
Source: Bano et al (1963)
The composition of Pleurotus species was observed to be approximately
similar to that of Agaricus compestris (Esselen and Fellers, 1946), except for the
tryptophan content, which is higher in Pleurotus species. Block and Mitchel
(1946), reported that mushroom protein is primarily deficient in phenylalanine
and methionine when compared with egg protein. At the same time when
compared with the proportions of essential amino acids required for satisfactory
mammalian growth, as reported by Rose (1937), using tryptophan level as unity,
the amino acid pattern of the mushroom protein appears to be adequate in all
other amino acids. In another study (Diez and Alvarez, 2001) on two
mushrooms Tricholoma portentosum and Tricholoma tereum; leucine,
isoleucine and tryptophan were found to be the limiting amino acids.
24
The composition of cultivated mushrooms and some common vegetables
were compared by Wooster (1954), and the results obtained were very
favourable (table 5).
Table 5: Composition of cultivated mushrooms and some common
vegetables on dry weight basis (dwb) per 100g (%)
Name Calories Moisture Fat Carbohydrate Protein (dwb)
Beetroot 42 87.6 0.1 9.6 19.9
Brinjal 24 92.7 0.2 5.5 15.1
Cabbage 24 92.4 0.2 5.3 18.4
Cauliflower 25 91.7 0.2 4.9 28.8
Celery 18 93.4 0.2 7.7 21.6
Green beans 98 74.3 0.4 17.7 26.1
Lima beans 128 66.5 0.8 23.5 22.2
Mushroom 16 91.1 0.3 4.4 26.9
Potato 83 73.8 0.1 19.1 7.6
Source: Wooster (1954)
According to USFDA (2005) and USDA (2006), mushrooms are among
the best plant-based sources of niacin (table 6).
Table 6: Vitamin content of some edible mushrooms (mg per 100g, dry
weight).
Mushroom Thiamin Riboflavin Niacin Vitamin C
Agaricus bisporus 1.1 5.0 55.7 81.9
Lentinus edodes 7.8 4.9 54.9 0.0
Pleurotus ostreatus 4.8 4.7 108.7 0.0
Volvariella volvacea 1.2 3.3 91.9 20.2
Source: Bahl (2000)
25
Analysis of Agaricus bisporus indicates high content of potassium,
phosphorus, copper, iron (table 7) but low content of calcium (Anderson and
Fellers, 1942).
Table 7: Mineral element content of some edible mushrooms (mg per 100g,
dry weight)
Mushroom Potassium Calcium Phosphorus Iron Sodium
A. bisporus 4762 23 1429 0.2 -
L. edodes 3793 33 1348 15.2 837
P. ostreatus - 98 476 8.5 61
V. volvacea 3455 71 677 17.1 374
Source: Chang and Tu (1978).
2.4 Chemical Composition of Meat
The chemical composition of lean meat is relatively constant over a wide
range of animals (Varnam and Sutherland, 1995). Variation is most marked in
the lipid content (table 8).
Table 8: Chemical composition of lean meat (%)
Species Water Protein Lipid Ash
Beef 70-73 20-22 4.8 1.0
Chicken 73 20-23 4.7 1.0
Lamb 73 20 5-6 1.4
Pork 60-70 19-20 9-11 1.4
Source: Varnan and Sutherland (1995).
Gracey and Collins (1992) reported a similar chemical composition for
lean beef (table 9).
26
Table 9: Chemical composition of lean beef (%)
Constituent Percentage
Water 75.0
Protein 19.0
Lipid 2.5
Carbohydrates (Glycogen) 1.2
Non protein Nitrogen 1.65
Minerals 0.65
Vitamins minute
Source: Gracey and Collins (1992).
In respect of amino acid composition (table 10), beef appears to have a
some what higher content of leucine, lysine and valine than pork and lamb and a
lower content of threonine (Ikeme, 1990). It was further stressed that breed, age
and specific muscle location affect the amino acid composition of meat.
Table 10: Essential amino acid composition of raw lean meat (g/100g)
Amino acid Beef Pork Lamb
Arginine 6.6 6.4 6.9
Histidine 2.9 3.2 2.7
Isoleucine 5.1 4.9 4.8
Leucine 8.4 7.5 7.4
Lysine 8.4 7.8 7.6
Methionine 2.3 2.5 2.3
Phenylalanine 4.0 4.1 3.9
Threonine 4.0 5.1 4.9
Tryptophan 1.1 1.4 1.3
Valine 5.7 5.0 5.0
Source: Lawrie (1991), Varnam and Sutherland (1995)
27
Table 11: Mineral content of raw meat (mg/100g)
Minerals Beef Mutton Pork Bacon
Sodium 69 75 45 975
Calcium 5.4 12.6 4.3 13.5
Magnesium 24.5 18.7 26.1 12.5
Iron 2.3 1.0 1.4 0.9
Phosphorus 276 173 223 94
Copper 0.1 0.1 0.1 0.1
Zinc 4.3 2.1 2.4 2.5
Potassium 334 246 400 268
Source: Lawrie (1991)
Vitamin B12 (cobalamin) which is naturally absent in plant tissues occurs
in meat (Ikeme, 1990). It was further stated that lean meat and liver are
excellent sources of niacin (table 12).
Table 12: Vitamin content of various meats (per 100g)
Vitamins Beef Veal Pork Bacon Mutton
Thiamin (mg) 0.07 0.1 1.0 0.4 0.15
Riboflavin (mg) 0.20 0.25 0.20 0.15 0.25
Nicotinic acid (mg) 5.0 7.0 5.0 1.5 5.0
Pantothenic acid (mg) 0.4 0.6 0.6 0.3 0.5
Biotin (µg) 3.0 5.0 4.0 7.0 3.0
Folic acid (µg) 10.0 5.0 3.0 0.0 3.0
Pyridoxine (mg) 0.3 0.3 0.5 0.3 0.4
Cobalamin (µg) 2.0 0.0 2.0 0.0 2.0
Vitamin A (IU) trace trace traces trace trace
Vitamin D (IU) trace trace traces trace trace
Vitamin C (mg) 0.0 0.0 0.0 0.0 0.0
Source: Lawrie (1991)
28
2.5 Problems of Meat Consumption
One reason for the negative effect of eating meat is the fat content
(Franklin, 2003). The negative contribution of fat is that it is involved in
increasing serum cholesterol in many individuals who consume animal fat in the
diet (Faustman, 1994). According to Vernon (1988), animal fat is a saturated
fat, which is associated with the condition of high blood cholesterol level for
some people. In the energy-rich countries of the industrialized west, the lipid
content of meat has been associated with obesity and artherosclerosis (Varnam
and Sutherland, 1995). It was further stated that the cholesterol and saturated
fatty acid content of meat have both been associated with a predisposition to
heart diseases. Franklin (2003), stated that a high intake of fat is associated with
an increased risk of both cancer and heart diseases.
With concern about the ingestion of fat, saturated fatty acids and
cholesterol and their contribution to arteriosclerosis and heart attack, there has
been considerable deliberation about the relationship of diet and health
(Faustman 1994). The USDA has recommended that no more than 30% of
calories be derived from fat (Kinsman, 1994 and Bastin, 2007) and 10% or less
from saturated fat (Kinsman, 1994; and Faustman, 1994).
Vernon (1988), reported that the exact relationship between diet and heart
diseases is not yet known. However, statistics proved that individuals living
within populations with diet relatively high in fat and cholesterol, such as in the
United States, have greater risk of having heart diseases than individuals within
populations that have diets containing less fat. In view of this Faustman (1994)
reported that current consumer attitudes and marketing trends discourage the
production of fat in meat animals.
A preponderance of studies carried out supported the link between red
meat and cancer (Karen, 2007). The high saturated fat content may affect cancer
development as well. It was further stressed that the cancer risk is not removed
by merely choosing lean red meats. The formation of heterocyclic amines
29
during high temperature processing of meat and nitroso compounds in presence
of nitrites, both carcinogenic, do not alone explain the greater risk of cancer
from red meat. The high colon cancer risk from red meat may be due to its
levels of the heme form of iron. Heme iron is found only in animal foods, and
the amount in beef is about twice that in chicken and fish. It has a different
chemical form than the iron in plant foods and supplements. Heme iron seems
to damage the lining of the colon and cause abnormal cell growth. Red meat
heme iron produces more nitroso compounds than iron from plant.
According to Lendon-smith (1985), meat eaters have problems of thyroid
insufficiency, gout, colon cancer, cancer, gas, constipation, fatigue, high blood
pressure, imnsonia, muscle ache, shortness of breath. Franklin (2003), stressed
that the human body has no real nutritional need of meat.
2.6 Mushroom Health Benefits
Mushrooms are well noted for their medicinal actions. According to
Beetz and Kustudia (2004), Asian traditions maintain that some specialty
mushrooms provide health benefits. Scientific research indicates that the major
actions of medicinal mushrooms are stimulating the immune system and
protecting against cardiovascular diseases, free radicals, mutagens, and toxins
(Moore, 2003). Various uses of mushrooms for medicine were reported by
Edwards (1975), and Bahl (2000), including for blood clotting, anticancerous,
antitumorous, antiviral, for reducing blood pressure, treatment of epilepsy,
control of heart diseases, rheumatoid arthritis, gout, jaundice, dropsy, intestinal
worms. According to Wasser (2002) several anti tumor compounds and
anticarcinogenic polysaccharides have been extracted from mushrooms
(Schizophyllum commune and Trametes sp) for commercial purposes in Japan.
Mushrooms are also reported to exhibit phytochemical properties. The
results of a study carried out with white bottom mushroom (Agaricus bisporus)
suggest that diets high in mushrooms may modulate the aromatase activity and
function in chemoprevention of cancer in menopausal women by reducing the
30
production of estrogen (Grube et al,, 2007). Chen et al (2006) illustrated the
anticancer activity in vitro and in vivo of mushroom extract and its major fatty
acid constituents. The physiologically relevant aromatase inhibitors in
mushroom were considered to be most likely conjugated linoleic acid and its
derivatives. One of the main phytochemicals of the tamogi-take mushroom
(Pleurotus cornucopiae) D-mannitol, was found to exhibit antihypertensive
effects (Hagiwara et al, 2005). It is also reported that fresh mushrooms contain
0.95% mannitol. According to Dubost (2006), mushrooms provide 2.8-4.9 mg
of ergothioneine per serving of white, and crimi mushrooms. Ergothioneine is a
naturally occurring antioxidant that also may help protect the body cells.
The consumption of shiitake mushrooms, a valuable source of zinc, iron
and potassium is reported by Graiones (2001) to help thin the blood and
consequently reduce the rate of heart disease. The low fat content of the wild
species of mushrooms studied by Chong et al (2007) indicated that the food is
suitable to be incorporated as/into a healthy and low fat diet especially for those
who are on weight management programme. They are as well expected to meet
the desires of hypertension and heart diseases patients as a special daily food for
consumption. Mushrooms were considered a possible substitute for meat as a
source of iron especially for those hardcore poor in the rural area of Sabah
where meat intake were almost impossible (Wasser, 2002).
2.7 Sensory Attributes of Mushroom
The taste and smell of mushrooms are important for both the
identification of species and for the oro-sensory sensation one experiences while
eating them (Hallock, 2008).
Cooked mushrooms give foods a delightful flavour due to the large
quantity of natural glutamic acid, the same flavour enhancer in monosodium
glutamate, but it does contain little sodium (Moore, 2003). Organoleptic tests of
the mushroom (Pleurotus sp) showed that it has acceptable flavour and biting
31
properties (Bano et al, 1963). The Chinese of the orient added the delicate fungi
to scent their sauces and soups (Bahl, 2000).
According to Doug (2008) the earthy fragrance and meaty texture of
shiitake mushroom enhances a wide variety of dishes. It was further reported
that the pom pom blanc mushroom has a firm texture and a flavour reminiscent
of fresh crab meat. The Sonoma brown oyster mushroom is an extremely
vigorous mushroom which has a firm texture when cooked and a meaty or
oyster-like flavour which will add texture and zest to most sauces or dishes. The
oyster mushrooms have been noted for centuries in the United States for their
unique flavour. According to Chong et al (2007), the acceptance of the
mushrooms shiitake (Lentinus edodes), oyster (Pleorotus ostreatus), and botton
(Agaricus bisporus) as a delicacy were well-established worldwide. They have
been used as food and food flavouring materials in soups for centuries, due to
their unique and subtle flavour. They are highly appreciated for their rich
aroma.
2.8 Physical and Sensory Qualities of Meat
The eating quality of meat is assessed ultimately by the consumer
(Malony, 1999). There are three main determinants of meat quality at the
consumer level; colour, juiciness and toughness/tenderness (Varnam and
Sutherland, 1995). According to Rowe (1983), qualities taken into consideration
include flavour, odour, appearance, juiciness and texture.
2.8.1 Colour
The red colour of meat is due to the presence of the heme protein,
myoglobin (Faustman, 1994). The degree of meat pigmentation is directly
related to myoglobin content (Faustman, 1994 and Malony, 1999). It was
further stressed that meat colour is an extremely important sensory
characteristic by which consumers make judgment of meat quality. The
perception of quality related to colour can be modified by other visual factors
(Varnam and Sutherland, 1995). Of importance among these, in red meat, is the
32
extent of marbling, the lipid tissue located between muscle fibre bundles in the
perimysial connective tissues. Marbling is positively associated with good
eating quality and can be an important factor influencing consumer choice.
However, concern over dietary fats now mean that quality can be associated
with virtual lack of visible fat.
2.8.2 Juiciness
Juiciness, according to Varnam and Sutherland (1995) and Malony
(1999), is related to the water holding capacity of the meat, and also to
marbling. Juiciness together with tenderness accounts for the overall eating
quality. Consumers may confuse the two factors when making assessment or
comparison. Juiciness is governed by how much fat, called marbling fat, is
woven within the muscle. Increased marbling fat improves eating quality factors
such as flavour intensity, juiciness, and texture. According to Malony (1999),
juiciness is an important component of meat texture and palatability and has two
components; the impression of wetness produced by the release of fluids from
the meat during the first few chews and juiciness resulting from the stimulating
effects of fat on the production of saliva.
2.8.3 Texture/Toughness/Tenderness
The texture of meat can be defined as the sensory manifestation of the
structure of meat and the manner in which this structure reacts to the force
applied during biting and specific senses involved in eating (Malony, 1999).
Toughness/tenderness rating is probably the most important of the meat quality
determinants (Rowe, 1983). According to Yashajahu and Clifton (1996)
tenderness, chewiness and toughness are measured in terms of the energy
required to masticate a solid food. These characteristics are further expressed as
the most difficult to measure precisely, because mastication involves
compressing, shearing, piercing, grinding, tearing, and cutting, along with
adequate lubrication by saliva at body temperature.
33
Structurally, there are two components in meat, the muscle fibres
(myofibrilla component) and the connective tissue (collagen) (Rowe, 1983 and
Malony, 1999). The connective tissue toughness is usually called the
background toughness and is regarded as not being substantially influenced by
treatment of meat post-slaughter. The contribution of toughness of meat due to
the muscle fibre component is termed myofibrilla toughness. This is the
toughness thought to respond to post-slaughter handling procedure and is
responsible for changes in meat toughness.
Collagen as the main component of muscle connective tissue is important
for the quality of meat. High collagen content affects meat tenderness as well as
the biological value of meat protein (Bosselmann, et al, 1995). Intramuscular
collagen must be regarded as a primary factor contributing to toughness of
meat. According to Barley (1984), more likely, the stabilization of collagen
through cross-linkage with advancing age leads to a lessening of meat
tenderness. The rise in pyridinoline content of muscle collagen probably
contributes essentially to this decrease in tenderness (Bosselmann, et al 1995).
As animal ages, there is an increase in heat stable collagen cross-links and a
resulting reduction in the amount of soluble collagen (Malony, 1999). Meat
tenderness can be characterized by measurement of shear force or by sensory
characteristics. The determination of pyridinoline is an objective method for
characterization of tenderness which derives from the meat and not from
possible changes by processing treatment (Bosselmann, et al, 1995). Gelation of
muscle protein contributes to the desirable texture and stabilization of fat and
water in processed meat products (Lan et al, 1995).
2.8.4 Flavour
The development of characteristic flavour of meat is dependent on heating,
when large number of chemical reactions occurs between the non volatile
compounds of meat. Many hundreds of volatile compounds are produced, but
probably a relatively small number play a significant role in determining flavour
34
and aroma (Varnam and Sutherland, 1995). According to Faustman (1994), the
lipid in food contributes significantly to perceived food flavours. It was further
stated that the eating quality of meat is improved because of fat, especially due
to juiciness and flavour enhancement. Malony (1999) further reported that the
flavours of meats can be associated with either the water in the meat or the fat
components of the tissue. Further more, the chemical components responsible
for meat flavour per se are found in the water-soluble fraction. It is indicated
that the flavour of meat increases, as the fat content increases. Thus, beef from
old animals is more intense in flavour than meat from younger animals.
2.9 Hamburger Production
2.9.1 Cut of Beef Used For Hamburger
Although any cut of beef may be used, chuck steak is one of the most
popular choices, due to its richness of flavour and balance of meat and fat
(Wikipedia, 2008). It is further stated that round steak is also frequently used.
2.9.2 Hamburger Composition and Ingredients
In many countries food laws define specific categories of ground beef and
what they can contain. For instance in the United States beef fat may be added
to hamburger, but not to ground beef if the meat is ground and packaged at
USDA inspected plant. A maximum of 30% fat by weight is allowed in either
hamburger or ground beef. Both hamburger and ground beef can have
seasonings, but no water, phosphates, extenders or binders added. According to
Uncyclopedia (2008), there are usually other accompaniments or condiments
piled onto the meat portion. These might include any combination of cheese,
vegetables (lettuce, tomato, onions, pepper, pickles hamsters) and sauces
(mayonnaise, ketchup, mustard, barbecue sauce, orange sherbet, etc).
Many authors/authorities (Southerland and Rhodes, 1992; Green, 2008,
etc) have formulated recipes for hamburger, with slight variations in ingredients
used, shape and methods of cooking.
35
3.9.3 Cooking of Hamburger
The commonly adopted methods of cooking hamburger are grilling
(Yashima, 2008; Southerland and Rhodes, 2008; and Green, 2008) and frying
(Green, 2008). The preparation and cooking time for hamburger is estimated
between 40 minutes and 60 minutes.
2.10 Importance of Hamburger
According to Yashima (2008), hamburger is a classic American food.
Hamburger was further described as century-old food and comfort food that
keeps peoples enjoyment, due to the varieties offered through the use of
different toppings and condiments. Mini burgers (one mouthful) can be served
as hot snacks at receptions (Foskett et al, 2004). Hamburger is a fast food as
well as snack.
36
CHAPTER THREE
3.0 MATERIALS AND METHODS
3.1 Raw Materials and Burger Production
The raw materials used for this study were fresh beef cuts (ribeye, chuck
and muscle of round) and oyster mushroom (Pleurotus sajor-caju). The raw
materials were procured from Ugbokolo market. The recipe and method of
Green (2008) were modified and used to prepare burgers with 0%, 20%, 40%
and 60% ratio of mushroom to beef for each muscle cut.
Burger Recipe
Beef mince 450g
Mushroom mince variable
Garlic cloves crushed 8g
Tomatoe kethup 10g
Mustard 4g
Egg lightly beaten 45g
Red chili finely chopped 20g
Onion small finely diced 50g
Spring onion sliced 50g
Bay leaves chopped 2g
Olive oil for frying 1kg
Source: modified from Green (2008)
37
Preparation of Burger
Cleaning of raw materials
Grinding of raw materials and other additives
Weighing and proportioning of raw materials
Addition of egg
Mixing of raw materials with other additives
Pressing and shaping to burger size
Frying of burger
Figure 1: Flow chart for the preparation of burger
Source: Modified from Green (2008)
3.2 Analysis
The following analyses were carried out on the burgers produced from
the beef/ mushroom combinations:
i. proximate analysis
ii. Mineral element analysis
iii. Analysis of vitamins
iv. Protein solubility
v. pH
The burgers were further subjected to:
i. Water activity (aw) study
38
ii. Sensory analysis
iii. Microbial analysis
3.2.1 Proximate Analysis
3.2.1.1 Moisture Content Determination
Moisture content was determined according to AOAC (1995). Stainless
steel oven dishes were cleaned and dried in the oven at 100oC for 1 hour to
achieve a constant weight. They were cooled in a desiccator. About 2g of
sample was placed in each dish and dried in the oven at 100oC under normal
atmospheric pressure until constant weight was achieved. The dishes together
with the samples were cooled in a desiccator, and weighed.
% moisture content = W2 – W3 X 100
W2 – W1
Where:
W1 = weight of dish
W2 = weight of dish + sample before drying
W3 = weight of dish + sample after drying.
3.2.1.2 Ash Determination
Ash determination was carried out according to AOAC (1995) method.
About 2g of sample was placed in silica dish which has been ignited, cooled and
weighed. The dish and sample were ignited first gently and then at 500 – 550oC
in a muffle furnace for 3 hours, until a white or grey ash was obtained. The dish
and content were cooled in a desiccator and weighed.
% Ash = W3 –W1 X 100
W2 – W1
Where: W1 = weight of dish
W2 = weight of dish + sample before ashing
W3 = weight of dish + sample after ashing
39
3.2.1.3 Crude Protein Determination
Crude protein was determined using the kjedhal method (AOAC, 1995).
The sample was digested first, distilled and titrated.
Two gram of sample was placed in the kjedhal flask. Anhydrous sodium
sulphate (5g or 4 tablets of kjedhal catalyst) was added to the flask. About 25 ml
of concentrated sulphuric acid was added with few boiling chips. The flask was
heated in the fume chamber until the sample solution became clear. The sample
solution was allowed to cool to room temperature, then transferred into a 250 ml
volumetric flask and made up to volume with distilled water.
The distillation unit was cleaned, and the apparatus set up. About 5ml of
2% boric acid solution with few drops of methyl red indicator were introduced
into a distillate collector (100ml conical flask). The conical flask was placed
under the condenser. Then 5ml of the sample digest was pipetted into the
apparatus, and washed down with distilled water. 5ml of 60% sodium hydroxide
solution was added to the digest. The sample was heated until 100ml of
distillate was collected in the receiving flask. The content of the receiving flask
was titrated with 0.049M sulphuric acid to a pink coloured end point. A blank
with filter paper was subjected to the same procedure.
% total N = (titre-Blank) X Normality of acid X N2
Weight of sample
Crude protein = % total N X 6.25
3.2.1.4 Determination of Fat
The fat content was determined according to AOAC (1995) soxhlet
extraction method. A 500 ml capacity round bottom flask was filled with 300 ml
petroleum ether, and fixed to the soxhlet extractor. Then 2g of sample was
placed in a labelled thimble. The extractor thimble was sealed with cotton wool.
Heat was applied to reflux the apparatus for about six hours. The thimble was
40
removed with care. The petroleum ether was recovered for reuse. When the
flask was free of ether it was removed and dried at 105oC for 1 hour in an oven.
The flask was cooled in a desiccator and weighed.
% fat = weight of fat X 100
weight of sample
3.2.1.5 Determination of Carbohydrates
Carbohydrate was determined by difference, according to AOAC (1995)
method, as follows:
% carbohydrate = 100 – (% moisture + % fat + % ash + % protein)
3.2.2 Mineral Element Analysis
3.2.2.1 Determination of Iron
Iron was determined following the phenanthroline method of Lee and
Stumm (1960).About 5 ml of digested sample was placed in a 50 ml volumetric
flask. Then about 3 ml of phenanthroline solution, 2 ml of hydrochloric acid and
1 ml of hydroxylamine solution were added to the sample in sequence. The
sample solution was boiled for 2 minutes and about 9 ml of ammonium acetate
buffer solution was added to the solution. The solution was diluted with water to
50 ml volume. The absorbance was determined at 150 nm wavelength.
Iron standard solution was prepared in order to plot a calibration curve to
determine the concentration of the sample. Standard solution containing 100
mg/ml of ferric ions was prepared from 1g pure iron wires. The wires were
dissolved in 100 ml concentrated nitric acid, boiled in a water bath and diluted
to 100 ml with distilled water after cooling. Standard solutions of known
concentrations were prepared by pipetting 2, 4, 6, 8 and 10 ml standard iron
solution into 100 ml volumetric flasks, and making it up to volume.
3.2.2.2 Determination of Magnesium
About 10 ml of the test solution was pipetted into 250 ml conical flask.
Then 25 ml of ammonia –ammonium chloride (NH3 – NH4CL) buffer, 25ml of
41
water, and 2 to 3 drops of Eriochrome Black –T indicator were added
respectively to the test solution. This was titrated against 0.01 N EDTA
solution. The volume of EDTA used was the volume equivalent of magnesium
in the admixture.
% magnesium = vol EDTA X MOL. EDTA X At. Wt .Mg X 100 X DF
1000 X weight of sample
3.2.2.3 Determination of Calcium
About 10 ml of the test solution was pipetted into 250 ml conical flask.
Then 25 ml of potassium hydroxide, 25ml of water, and a pinch of calcium
indicator were added to the test solution. It was titrated against 0.01N EDTA
solution to an end point. The volume EDTA was the volume equivalent of
calcium in solution.
% calcium = vol EDTA X MOL. EDTA X At. Wt.Ca X 100 XDF
1000 X weight of sample
3.2.2.4 Determination of Phosphorus Using Spectrophotometer
Phosphorus in the sample was determined using Spectrophotometer
(Spect. 21 D EEC Medical) by the molybdate method, using hydroquinone as a
reducing agent. About 5 ml of the test solution was pipetted into 50 ml
graduated flask. Then 10 ml of molybdate mixture was added and diluted to
mark with water. It was allowed to stand for 15 minutes for colour
development. The absorbance was measured at 400 nm against a blank. A curve
relating absorbance to mg phosphorus present was constructed. Using the
phosphorus standard solution, and following the same procedure for the test
sample, a standard curve was plotted to determine the concentration of
phosphorus in the sample.
% phosphorus = graph reading X solution volume
100
42
3.2.2.5 Determination of Sodium and Potassium
Sodium and potassium were determined using a flame photometer
(Gallenkamp Flame Analyser). Potassium and sodium standards were prepared.
The standard solutions were used to calibrate the instrument read out. The meter
reading was set at 100% E (emission) to aspire the top concentration of the
standards. The % E of all the intermediate standard curves was plotted on linear
graph paper with these readings.
The sample solution was aspired on the instrument, and the readings (%
E) were recorded. The concentration of the element in the sample solution was
read from the standard curve.
% sodium = ppm x 100 X DF
1 million
% potassium = ppm X 100 X DF
1 million
3.2.2.6 Determination of Zinc
Zinc was determined by Dithizone method. About 5 ml of the digested
sample was placed in a test tube. Then 5 ml of acetone buffer was added to the
sample and 1 ml of sodium thiosulphate solution was added and mixed
thoroughly. Then10ml of dithizone was added to the mixture, and shaken
vigorously for 4 minutes. The absorbance was measured at 535 nm wavelength
using spectrophotometer (Spect. 21 D EEC Medical). Standard solutions were
prepared to find the concentration of the sample.
Preparation of Stock Solution
About 1g of oven dried, milled sample was ashed in a muffle furnace at
600oC for 4 hours. The ash was dissolved with 10 ml 90% HCL. The solution
43
was filtered through No 1 whatman filter paper into 100 ml volumetric flask.
The residue was washed with water until the flask was half filled. The residue
was removed and the flask was made up to mark with water. The stock solution
was stored for the determination of calcium, magnesium, phosphorus, sodium,
potassium and other minor elements.
3.2.4 Analysis of Vitamins
3.2.4.1 Determination of Thiamin (B1)
Thiamin was determined using Onwuka (2005) modified procedure based
on AOAC (1995).
About 2 g of sample was taken, onto which 75 ml of 0.2 N Hydrochloric
acid was added. The mixture was heated to boil on a water bath. After cooling,
5 ml of enzyme solution was then added and incubated at 37oC over night. The
mixture was placed in 100 ml flask and made to volume with water. It was
filtered and purified by passing it through silicate column. About 5 ml of the
acidic potassium chloride eluate was taken in a conical flask and 3 ml of
alkaline ferricyanide solution and 15 ml of isobutanol were added to the eluate
and shaken for 2 minutes. It was allowed to separate, and the alcohol layer was
taken. Then 3 g of anhydrous sodium sulphate was added to the isobutanol
extract.
About 5 ml of thiamin solution was measured into another 50 ml
stoppered flask. The oxidation and extraction of thiochrome as already carried
out with the sample was repeated using the thiamin solution. Then 3 ml of
sodium hydroxide was added to the blank instead of alkaline ferricyanide.
The sample and the blank were prepared by taking 5ml each. The
flourimeter was set to excitation wavelength of 360 nm and emissive
wavelength of 435 nm. The instrument was adjusted to zero deflection with 0.1
44
N sulphuric acid and 100 against the standard. The flourimenter readings were
taken with the sample and the blank.
Calculation:
% Thiamin = w
Xv
XXy
x 10025
5
1
Where: w = weight of sample
x = reading of the sample – standard blank
y = reading of thiamin standard – standard blank
v = volume of solution used for test on the column.
3.2.3.2 Determination of Riboflavin
Onwuka (2005) modified AOAC (1995) method was used.
About 2 g of sample was placed in a conical flask. Then 50 ml of 0.2N HCL
was added to the sample, and boiled for 1 hour and thereafter cooled. The pH
was adjusted to 6.0 using sodium hydroxide. 1 N HCL was added to the sample
solution to lower the pH to 4.5. The solution was filtered into 100 ml measuring
flask and made to volume with water.
In order to remove interference, two tubes were taken, labeled 1 and 2.
About 10ml of filtrate and 1 ml of water were added to tube 1. About 10 ml of
filtrate and 1 ml of riboflavin standard were added to test tube 2. Then, 1 ml of
glacial acetic acid was added to each tube and mixed. Then 0.5ml of 3%
KMnO4 solution was added to each tube. They were allowed to stand for 2
minutes after which 0.5ml of 3% H2SO4 was added and mixed thoroughly.
The flourimeter was adjusted to excitation wavelength of 470 nm and
emission wavelength of 525 nm. The flourimeter was adjusted to zero deflection
against 0.1N H2SO4, and 100 against tube 2 (standard). The fluorescence of tube
45
1 was read. 20 ml of sodium hydrogen sulphate was added to both tubes and the
fluorescence measured within 10 seconds. This was recorded as blank reading.
Calculation:
Riboflavin mg/gw
Xxy
x 1
−
=
Where: w = weight of sample
x = reading of sample – blank reading
y = reading of sample + standard (tube 2) - reading of
sample + standard blank.
3.2.3.3 Determination of Niacin
Niacin was determined by Pearson (1976) using spectrophotometer
(Spect. 21 D EEC Medical). About 2g of sample was weighed into a conical
flask and 20 ml of 0.5M NaOH was added into the flask and stirred with
magnetic stirrer for 30 minutes. The solution was filtered into clean container.
Then 5 ml of the extract was transferred into a test tube and 4 ml of 0.1 N KCL
and 0.1N HCL solutions were added into the extract and allowed to stand for
yellow colour development. The absorbance was measured at 261 nm. A blank
solution was prepared. Niacin was calculated using the test solution, blank
solution and standard solution.
Calculation:
Niacin mg/g = Absorbance of test sample X conc. of standard (5mg/dl)
Absorbance of standard
3.2.3.4 Determination of Vitamin C
The AOAC (1995), 2, 6-dichlorophenol titrimetric method was used to
determine vitamin C. About 2g of the sample was extracted by homogenizing in
acetic acid solution. Vitamin C standard solution was prepared by dissolving
46
50mg standard ascorbic acid tablet in 100 ml volumetric flask with water. The
solution was filtered and 10 ml of the clear filtrate was added into a conical
flask in which 2.5 ml acetone has been added. This was titrated with indophenol
dye solution (2, 6 dichlorophenol indophenol) for 15 seconds. The procedure
was followed for the standard as well.
Calculation:
mg ascorbic acid/1g sample = C X V X (DF/WT)
Where:
C = mg ascorbic acid 1 ml dye
V = volume of dye used for titration of diluted sample
DF = dilution factor
WT = weight of sample (g)
3.2.3.5 Determination of Vitamin A
The AOAC (1995) method using the colorimeter was adopted for vitamin
A determination. Pyrogallol (antioxidant) was added to 2g sample prior to
saponification with 200ml alcohol KOH. The saponification took place in water
bath for 30 minutes. The solution was transferred to a separating funnel where
water was added. The solution was extracted with 1-2.5ml of hexane. The
extract was washed with equal volume of water. The extract was filtered
through filter paper containing 5g anhydrous Na2 S04 into volumetric flask. The
filter paper was rinsed with hexane and made up to volume. The hexane was
evaporated form the solution and blank. 1ml chloroform and SbL3 solution
were added to the extract and blank. The reading of the solution and blank were
taken from the colorimeter (Photo-electric Colorimeter A E 11 D) adjusted to
zero absorbance or 100%.
Calculation:
mg Vitamin A = A620nm X SLx (v/wt)
where: A620nm = absorbance at 620nm
47
SL =slope of standard curve (Vit.A conc.) ÷ A620 reading
V = Final volume in colorimeter tube
Wt = weight of sample.
3.2.4 Determination of Protein Solubility
Soluble protein was determined using the method of Obanu (1978).
About 0.2g of the sample was weighed into a test tube containing 20ml of 3%
sodium deodecyl sulphate (SDS) and 1% β mercapto ethanol. The mixture was
allowed to stand at room temperature for a period of 30 minutes, and then in
boiling water bath for another 30 minutes, then filtered hot. The residue
represented the insoluble fraction. The nitrogen content of each sample
(fraction) was determined using the micro-kjedahl distillation technique. The
nitrogen content of the filtrate T1 and the residue T2 was used to calculate the
percentage soluble protein.
% soluble protein = 10021
1 XTT
T
+
3.2.5 Determination of pH
The pH of the samples was determined by potentiometric method. About
50ml of water was added to 5g of ground sample in a conical flask. It was
shaken until all the particles were evenly suspended and free of lumps. The
mixture was digested for 30 minutes, shaking it frequently and allowing it to
stand for 10minutes at intervals. The supernatant was decanted into 250 ml
beaker, and the pH was determined using electrode and potentiometer
standardized with buffer solutions of pH 4.01 and 9.01.
3.2.6 Determination of Water Activity (aw)
Water activity was determined using the water activity meter (model
5083). About 10g of the burger sample was placed in the water activity bowl,
and allowed to stay for three hours to equilibrate, after which the value was read
from the meter.
48
3.2.7 Microbial Analysis
3.2.7.1 Total Viable Count Determination
Pour plate method as described by Harrigan and McCance (1976) was
used. About 1g of the sample was macerated into 9 ml of Ringers solution and
mixed thoroughly by shaking. This was further diluted to obtain 10-2
and 10-3
concentration. Then 0.1 ml dilution was transferred from each dilution bottle
into the corresponding plate and 15ml of sterile nutrient agar medium was
poured and mixed thoroughly with the innoculum by rocking the plates. The
plates were incubated at 38oC for 24 hours after which the colonies formed were
counted and expressed as colony forming units per gram (Cfu/g).
3.2.7.2 Coliform Count Determination
The pour plate method of Harrigan and McCance (1976) was used. About
9 ml of sterilized violet red bile agar was put into each plate containing 1 ml of
innoculum from 10-3
dilution. The plates were shaken gently to mix the content
properly, then, the content was allowed to set and subsequently incubated at
37oC for 72 hours. After incubation the number of colonies which appeared with
dark red or pink centres was counted. This was expressed as colony forming
units per gram (cfu/g).
3.2.7.3 Mould Count Determination
The pour plate method as described by Harrigan and McCance (1976)
was still used. About 0.1 ml of the sample dilution was transferred from each
dilution into corresponding plates and 15ml of sterile Sabouraud Dextrose Agar
(SDA) medium was poured and mixed thoroughly with the innoculum by
rocking the plates. The plates were incubated at ambient temperature for three
days after which colonies formed were counted and expressed as colony
forming units per gram (cfu/g).
3.2.8 Sensory Analysis
A sensory panel of 10 Judges was constituted and trained to assess the
sensory attributes of the burger samples. The samples were assessed for
49
texture/mouth feel, taste, odour, colour, and general acceptability on a nine
point hedonic scale of likes and dislikes, with 9 standing for like extremely and
1 dislike extremely.
3.9 Experimental Design
The experimental design used for this study is split plot in randomized
complete block design (RCBD). Studentised Duncan multiple range test was
used to separate the means.
50
CHAPTER FOUR
4.0 RESULTS AND DISCUSSION
4.1 Contribution of mushroom to the proximate composition of hamburger.
Table 12 shows the proximate composition of the burger samples. The
addition of mushroom resulted in a general progressive decrease in protein, fat,
moisture and ash content, and an increase in carbohydrate content.
Protein content
On wet bases beef is known to contain 20% crude protein while on dry matter
bases it contains approximately 80% crude protein but mushroom is reported to
contain approximately 35% crude protein; hence inclusion of mushroom to the
beef burger reduced the protein content of meat through dilution effect. Thus
samples without mushroom had the highest amount of protein content. This is
illustrated by the ribeye muscle without mushroom which contained 28.45-
+0.02%crude protein compared with same muscle with 60% mushroom which
contained 25.77+0% crude protein. Similar observations were made regarding
muscle of round and chuck muscle.
Though Bano et al (1963) and Mshandete and Cuff (2007) reported that
mushrooms are better sources of proteins compared with many fruits and
vegetables, the quantity is not high enough as to compete with meat proteins
hence the observed reduction in protein content of burger samples with
mushroom. According to Allan (2010) and Organic Mushroom Growing Kits
(2010) the protein content of fresh oyster mushroom is 4.94g (9% of the DV of
proteins) and 3.0g (5% of the DV of proteins) per 100g respectively. Allan
(2010) further reported that mushroom protein contributes about 10% of the
daily value (DV) of proteins. Crisan and Sands (1978); FAO (1991), Chang and
Miles (1989), and NIIR Board (2006) reported that on a dry weight basis (dwb)
mushrooms normally contain 19-35% and 21-49% crude proteins as compared
to rice (7.3%), wheat (12.9%) and corn (9.4%); and legumes (20-49%)
51
respectively, hence mushrooms rank above most vegetables and cereal foods
and compare favourably with legumes in protein content. In accordance with
NIIR Board (2006) mushrooms can substitute the non vegetable diet and can as
well provide available source of high quality proteins for vegetarians. While
cereal is reported to contain low level of lysine, the lysine content of mushroom
is fairly high (FAO, 1991). In the light of this, mushrooms can be good
supplements to cereals, as reported by Chang and Boswell (1996) and would
help in over-coming amino acid deficiency, particularly lysine deficiency in
accordance with NIIR Board (2006).
Table 13: Proximate composition of hamburger samples with and without mushroom*
Muscle
cut
Level of
mushroom (%)
Protein (%) Fat (%) Moisture
(%)
Ash (%) Carbohydrate
(%)
Ribeye 0 28.45± 0.02f
12.47±0.04h
54.40 ±0.03h 3.84±0.02
f 0.88± 0.22
a
20 27.51±0.00e
11.39±0.03f
52.80±0.02g
3.60±0.02e
4.70± 0.06b
40 26.69±0.32d
10.06±0.07c
50.46±0.12f
3.22±0.12bc
8.24± 0.84d
60 25.77± 0.00c
9.23 ±0.09a
47.83± 0.03bc
3.250±0.05c
13.92± 0.15h
Round 0 30.63±0.02h 12.06±0.08
g 52.38 ± 0.11
g 3.97 ±0.03
g 0.95 ± 0.16
a
20 26.76 ±1.00d
10.96±0.02d
50.49±0.14f
3.48±0.06d
9.01± 0.60e
40 25.12±0.02b
9.81±0.01b
48.16±1.01c
3.02±0.07a
13.22± 0.21g
60 24.12 ± 0.12a
9.29 ± 0.06a
47.40±0.34b
3.09±0.10a
16.09± 0.27i
Chuck 0 30.81 ± 0.04h
13.63± 0.15i
50.76 ±0.05f
3.92 ±0.02fg
0.88 ± 0.17a
20 29.27 ± 0.00g
11.41 ±0.13f
49.84 ±0.03e
3.48 ±0.01d
6.01 ± 0.10c
40 27.53 ±0.03e
10.86 ±0.02e
47.98 ±0.04c
3.21 ±0.01bc
10.43 ± 0.02f
60 26.64 ±0.01d
9.86 ±0.02b
46.07 ±0.05a
3.13 ±0.11ab
14.33 ± 0.13h
*Values are in mean ± SD, and means with the same superscript in the same column are not
significantly different (P > 0.05).
Differences in protein content between beef burgers from different
muscles were observed and these differences were attributed to the anatomical
differences. The protein content of chuck muscle burger samples was generally
higher than those of muscle of round and ribeye burger samples. The protein
content of muscle of round and chuck muscle burger samples without
mushroom was not significantly different (P>0.05).Among burger samples
without mushroom chuck muscle sample had the highest (30.81 ± 0.04%)
protein content, while ribeye sample had the lowest (28.45 ± 0.2%) protein
content. Among burger samples with mushroom, chuck sample with 20%
52
mushroom had the highest (29.27 ± 0.0%) protein content, while muscle of
round sample had the least (24.12 ± .12%) protein content. This is however
higher than the protein content of rice (7.3%), wheat (12.9%), and corn (9.4%)
on dwb reported by Chang and Buswell (1996) and Chang and Mshigeni
(2001). A serving size of 85g lean beef and 100g beef patty contribute 51% and
45% of the DV of proteins (USDA Research Service, 2005; and USDA, 2010)
respectively. Estimated contribution of burgers without mushroom as found
from this study (52%) of the DV of proteins is higher than those reported by
USDA (2005) and USDA (2010. The progressive inclusion (20%, 40%, and
60%) of mushroom showed progressive decrease in protein content due to
dilution effect. Progressive inclusion of mushroom also showed significant
differences (P < 0.05) in the protein content among all the burger samples
irrespective of the muscle cuts. Burgers with 20%, 40% and 60% mushroom
contribute 48%, 46% and 44% of the DV of proteins respectively.
Fat content
The fat content of fresh lean beef as reported by Gracey and Collins
(1992); and Varnan and Sutherland (1995) is 2.5% and 4.8% respectively. The
fat content of burgers observed in this study was higher than these values. This
could be attributed to concentration effect following processing as well as the
nature of beef cuts used. However on addition of mushroom the fat content was
reduced, implying that addition of mushroom caused a dilution effect. This is
illustrated by burger samples from ribeye muscle without mushroom which
contained 12.47±0.04% but reduced to 9.23±0.09% on addition of up to 60%
mushroom. Similar observation was made with burgers from the muscle of
round and chuck muscle.
The fat content of chuck muscle burger samples was generally higher
than those of muscles from round and ribeye burger samples (table 12). The fat
content of burger samples without mushroom (0% level of mushroom) differed
53
significantly (P < 0.05) from one another for the three muscle cuts. The
decrease in fat content of burger samples with increase mushroom levels could
have been due to the low fat content (0.65%) of mushroom (Pleorotus sp)
reported by Gray (1970) and Bano (1976). This is a healthy development since
according to Diet and Fitness Today (2010 b) all animal fats such as those in
beef, poultry and dairy products are saturated. It is further reported that the
saturated fats are the very unhealthy fats. They make the body produce more
cholesterol which will increase the blood cholesterol levels. A serving size of
one burger sandwich (137g) contains 22.9g (35% of the DV) total fats, (8,4g
saturated fatty acids), 2.1g polyunsaturated fatty acids and 71mg cholesterol
(Nutrition Factsheet, 2010 a). Eating Well (2010) reported that a 90/10 ration of
meat/mushroom burger contains 6g fat (2g saturated, 2g monounsaturated and
28mg cholesterol). The inclusion of mushroom in view of its low fat content,
high unsaturated fatty acids (Solomko et al, 1984; Barros et al, 2007; Kavishree
et al, 2008; Diez and Alvarez, 2001; Heleno et al, 2009) and being free from
cholesterol invariably implies a reduction in the saturated fats, cholesterol and
an increase in the unsaturated fats content of the burgers with mushroom. This
will result in the alleviation of the health risk of red meat reported by Franklin
(2003), Faustman (1994), Vernon (1988), Varnan and Sutherland (1995), Karen
(2007) and Lendon-Smith (1985). The fat contents of all the burger samples
observed in this study, though higher than that reported by Eating Well (2010)
for a 90/10 ration of meat/mushroom burger are lower than that reported
(Nutrition Factsheet, 2010 a) for a serving size (137g) burger sandwich. At 20%
level of mushroom, the fat content of ribeye and chuck burger samples were not
significantly different (P>0.05), yet differed significantly (P<0.05) from all
other samples. At 40% level of mushroom, all the burger samples differed
significantly (P<0.05) from one another. At 60% level of mushroom the fat
content of ribeye and muscle of round burger samples were not significantly
different (P>0.05). Among burgers without mushroom chuck sample had the
54
highest fat content (13.63 ±15%).The estimated daily value (DV) of burgers
without mushroom from this study is 20%, while burgers with 20%, 40% and
60% mushroom contribute 17%, 16% and 15%. These are lower than the value
reported by Nutrition Factsheets (2010).
Moisture Content
The moisture content of burger samples was generally reduced sequel to
processing. The inclusion of mushroom was still shown to cause progressive
decrease in moisture content of burger samples. The higher moisture content of
burger samples without mushroom could imply that beef has a higher water
holding capacity than mushroom. This observation is illustrated by burger
samples from ribeye muscle which contains 54.40 ± 0.03%, but upon the
inclusion of mushroom up to 60%, reduced to 47.83 ± 0.03%. Similar trend was
observed for burgers from muscle of round and chuck muscle.
The moisture content of burger samples without mushroom (0% level of
mushroom) differed significantly (P < 0.05) from one another for the three
muscle cuts. Similarly at 20% level of mushroom, all the burger samples
differed significantly (P < 0.05). At 40% level of mushroom muscle of round
and chuck burger samples were not significantly different (P > 0.05). At 60%
level of mushroom ribeye and muscle of round burger samples were not
significantly different (P>0.05). Incidentally it was observed that ribeye burger
sample with 40% mushroom, muscle of round burger sample with 20%
mushroom and chuck burger sample without mushroom were not significantly
different (P > 0.05) in their moisture content. Similarly ribeye burger sample
with 60% mushroom, muscle of round and chuck burger samples with 40%
mushroom respectively were observed not to be significantly different (P >
0.05). Among burgers with and without mushroom ribeye samples had the
highest moisture content being 54.40% and 52.80% (for 20% mushroom)
respectively.
55
Ash Content
The ash content of fresh lean beef and mushroom is 1% and 0.97% as
reported by Varnan and Sutherland (1995); and Bano et al (1963) respectively.
The ash content of burger samples observed in this study is higher than these
values. This might be attributed to concentration effect as well as contribution
from the items in the recipe. However the addition of mushroom was shown to
reduce the ash content of burger samples. This might be due to dilution effect.
This is illustrated by burger samples from ribeye muscle which contains 3.84 ±
0.02%, but which upon inclusion of mushroom up to 60%, contains 3.25 ±
0.05% ash. Similar trend was observed for burgers from muscle of round and
chuck muscle respectively.
At 20% level of mushroom the ash content of muscle of round and chuck
burger samples were not significantly different (P > 0.05). At 60% level of
mushroom ribeye and chuck burger samples were found not to be significantly
different (P > 0.05) in their ash content as well. It was still observed that muscle
of round burger samples with 40%, and 60% mushroom, and chuck burger
sample with 60% mushroom were not significantly different (P>0.05) in their
ash content. The ash content of ribeye burger samples with 40% and 60%
mushroom did not show significant difference (P > 0.05) from chuck burger
sample with 40% mushroom. Though significant difference (P < 0.05) existed
between ribeye and muscle of round burger samples without mushroom, both
were not found to differ significantly (P> 0.05) from chuck burger sample
without mushroom. Among burger samples without mushroom, muscle of
round had the highest (3.97±.05%) ash content. Ribeye burger sample with 20%
mushroom had the highest ash content (3.60%) among burgers with mushroom.
The ash content observed in all the samples is higher than that reported for fresh
meat and mushroom, but comparable with that (2.28% - 3.29%) report by Nurul
et al., 2009) for cooked beef frankfurters.
56
Carbohydrate Content
The carbohydrate content of meat (beef) is negligible (1.2%) according
to Gracey and Collins (1992). The carbohydrate content of burger samples
without mushroom is lower than this value. However, with the addition of
mushroom the carbohydrate content increased progressively. This observation is
illustrated by burger samples from ribeye muscle without mushroom which
contains 0.88 ± 0.22%, but upon the inclusion of mushroom up to 60%, the
carbohydrate content increased to 13.92 ± 0.15%. Similar trend is observed for
burger samples from muscle of round and chuck muscle respectively.
The carbohydrate content of all the burger samples without mushroom is
found to be statistically (P > 0.05) the same (Table12). Similarly, at 60% level
of mushroom, the carbohydrate content of ribeye and chuck burger samples
were not significantly different (P>0.05). Significant differences (P < 0.05)
were observed among all the other burger samples. Generally, the carbohydrate
content of burger samples without mushroom was low. Muscle of round burger
sample with 60% mushroom had the highest (16.09±0.27%) carbohydrate
content. Mushrooms are reportedly high in manitol and trehalose (Hagiwara, et
al., 2005; Barros et al., 2007; Heleno et al., 2009; Mc connel and Esselen,
1947), and manitol is found to exhibit antihypertensive effects. Mushrooms are
also shown (Barlow, 2010) to be rich in total dietary fibres including those
associated with cholesterol lowering (chitin) and healthy hearts (Beta-glucan).It
is expected that the higher the proportion of mushroom in the hamburgers the
better the heath values of the burgers. The plain burger without mushroom is
found to contribute 0.31% (average) of the DV for carbohydrates. The burgers
with 20%, 40%and 60% mushroom contribute 2%, 4% and 5% of the DV of
carbohydrates respectively.
57
4.2 Contribution of mushroom to the mineral element composition of
hamburger
From table 13, it is observed that the mineral element content of the
burger samples decreased generally with progressive addition of mushroom.
Magnesium content
The magnesium content of raw beef has been reported to be about 24.5
mg/100g. As shown in table 13, the magnesium content of burgers were lower
than this value , suggesting that addition of mushroom reduced the magnesium
content of burgers made from beef .Hence the higher the quantity of mushroom
in the product the lower the quantity of magnesium. This is illustrated by
burgers made from ribeye muscle in which the sample without mushroom had
21.17+0.08mg/100g magnesium but which reduced to 3.61+ 0.73 mg/100g on
replacement of beef with mushroom up to 60%.Similar trend has been observed
for muscle of round and chuck muscle. The reduction of magnesium content of
beef by the presence of mushroom has been attributed to low magnesium
content of mushroom.
The magnesium content of burger samples without mushroom differed
significantly (P<0.05) between cuts. This has been attributed to anatomical
differences. Ribeye burger sample without mushroom had the highest
(21.17±0.08mg/100g) magnesium content. However among burger samples
with mushroom, the magnesium content of muscle of round burger samples
were found to be generally higher at all levels of mushroom inclusion. At 20%
level of mushroom, the magnesium content of ribeye and chuck burger samples
were found to be statistically (P>0.05) the same. Although ribeye and muscle of
round burger samples were still statistically similar (P>0.05), muscle of round
and chuck samples differed significantly (P<0.05). At 40% level of mushroom,
ribeye and chuck burger samples did not show significant differences (P>0.05),
however both are significantly different (P<0.05) from muscle of round burger
58
sample with the same level of mushroom. At 60% level of mushroom, the
magnesium content of muscle of round and chuck burger samples were not
significantly different (P>0.05) from ribeye burger sample. Muscle of round
burger sample with 20% mushroom had the highest (15.32 ± 0.05mg/100g)
magnesium content while ribeye burger with 60% mushroom had the lowest
(3.61 ± 0.73mg/100g) magnesium content among burger samples with
mushroom.
Table 14: Mineral element composition of hamburger with and without mushroom*
Muscle
cut
Mushroom
(%)
Magnesium
(mg/100g)
Iron
(mg
/100g)
Phosphorus
(mg/100g)
Zinc
(mg/100g)
Calcium
(mg/100g)
Sodium
(mg/100g)
Potassium
(mg/100g)
Ribeye 0 21.17±
0.08i 2.33±
0.11g 122.25±
1.38fg
5.25±
0.00h 25±
0.001e 121 ±
0.001e 469 ±
0.003a
20 14.73±
0.49ef 1.72±
0.07d 109.81±
0.05e 4.13 ±
0.0g 20±
0.001c 113 ±
0.004d 466 ±
0.023a
40 9.33 ±
0.16c
1.44±
0.02c
102.27±
0.04d
3.18±
0.00d
17±
0.000ab
92 ±
0.002b
434 ±
0.013a
60 3.61 ±
0.73a 1.34 ±
0.08bc 80.99±
1.04a 2.09±
0.02a 18±
0.001ab 86 ±
0.002a 426 ±
0.008a
Round 0 20.11±
0.34h
2.17±
0.03f 124.62 ±
0.07g 6.31 ±
0.00j 27 ±
0.001f 152 ±
0.001f 460 ±
0.011a
20 15.32 ±
1.68f
1.68±
0.00d
112.63±
0.86e
4.14±
0.00g
22±
0.001d
93 ±
0.002b
453 ±
0.004a
40 10.63±
0.22d 1.42±
0.00c 109.93±
0.92e 3.97±
0.00f 19±
0.001bc 82 ±
0.002a 452 ±
0.003a
60 4.90 ±
0.35b
1.26 ±
0.00ab
85.91±
0.50b
2.50±
0.00b
17±
0.000ab
81 ±
0.001a
434 ±
0.002a
Chuck 0 19.40 ±
0.18g
2.00 ±
0.03e
120.44 ±
0.02f
6.36
±0.00k
23 ±
0.001d
112 ±
0.002d
457 ±
0.019a
20 14.34 ±
0.23e 1.64 ±
0.01d 109.99±
0.04e 5.41 ±
0.00i 19 ±
0.001bc 101 ±
0.001c 431 ±
0.008a
40 9.72 ±
0.20c
1.41 ±
0.02c
102.56 ±
0.54d
3.73 ±
0.00e
17 ±
0.001a
101 ±
0.001c
439 ±
0.001a
60 4.76 ±
0.43b
1.21 ±
0.01a
93.32 ±
0.06c
2.77 ±
0.00c
17±
0.001a
94 ±
0.006b
438 ±
0.003a
*Values are in means ± SD and means with the same superscript in the same column are not
significantly different (P>0.05).
The Recommended Daily Allowance (RDA) for magnesium is 420 mg
(Diet and Fitness Today, 2010 a; and Wikipedia, 2010). The burger samples
without mushroom, as found from the study, contribute 5% (average) of the DV
of magnesium. The magnesium content of raw beef as reported by
Lawrie(1991) is 24.5mg (5.8% DV). Due to dilution effect from mushroom,
59
burger samples with 20%, 40%, and 60% mushroom were found to contribute
1% of the DV of magnesium respectively. A serving size of one sandwich
(137g) provides 27 mg (6.4% DV) of magnesium. This higher value could have
arisen from the accompaniments (Uncyclopedia, 2008) and the bun used to
prepare the burger sandwich. When served as sandwich with the necessary
accompaniments, the magnesium content of burgers with mushroom might
improve, though hamburger is generally not a good source of magnesium
having a DV of 6.4, and mushroom is not reported as a notable source of
magnesium.
Iron content
The iron content of raw beef is reported to be about 2.3mg/100g (Lawrie,
1991). Table 13 shows that the iron content of burgers reduced gradually from
2.33mg/100g as observed with ribeye burger sample without mushroom to 1.34
+0.08mg/100g as meat was replaced with up to 60% mushroom. This
observation indicates that the iron content of mushroom is lower than that of
meat, hence as the quantity of mushroom was increased the iron content of
burgers consequently reduced, due to dilution effect. Similar trend was observed
for burgers made with muscle of round and chuck muscle.
The iron content of burger samples without mushroom was found to be
statistically different (P<0.05). This has been observed to be due to anatomical
differences. Similarly burger samples without mushroom also differed
significantly (P<0.05) from those with mushroom. The iron content of burger
samples with 20% and 40% mushroom respectively were found to be statically
the same (P>0.05) at the various levels of mushroom. At 60% level of
mushroom, no significant difference (P>0.05) was observed between ribeye and
chuck, and muscle of round and chuck burger samples respectively. However
significant difference (P<0.05) was observed between ribeye and chuck burger
samples at the same level of mushroom. Among the burger samples without
60
mushroom, ribeye sample had the highest (2.33±0.11 mg /100g) iron content,
while ribeye burger sample with 20% mushroom had the highest (1.72 ±
0.07mg/100g) iron content among burgers with mushroom. Chuck burger
sample with 60% mushroom had the lowest (1.21 ± 0.01 mg /100g) iron
content.
According to Nutrition Factsheets (2010 b) and Wikipedia (2010), the
United State, RDA for iron used as the standard in nutrition labelling of foods is
18 mg. Nutrition Factsheets (2010 b) further reported that a good source of iron
contributes at least 10% of the US RDA for iron in a selected serving. This
study found that all the burgers without mushroom contain more than 10% of
the DV for iron based on RDA of 18mg. The inclusion of mushroom resulted in
reduced daily value of iron. The DV of burgers with 20%, 40% and 60%
mushroom were found to be 9%, 8%, 7% (average) respectively. The 12% DV
of burgers without mushroom is lower than that (19%) reported by Nutrition
Factsheets (2010 a) for a serving size of one burger sandwich (137g) but
comparable with the 14% and 13% reported by Cattlemens Beef Board and
National Cattlemens Beef Association (2006) and Lawrie (1991) for a serving
size of 85g lean beef and raw beef (per 100g) respectively .Since the muscles
used in this study were not very lean, the proportion of fat could have effect on
the iron content. The low iron content observed in this study may be enhanced
by the accompaniments and bun that would be used in the sandwich. A food
providing 5% of the DV or less is a low source of iron while a food that
provides 10-19% of the DV is a good source (Nutrition Factsheets, 2010 a). It is
further indicated that foods that provide lower percentages of the DV also
contribute to a healthy diet. Iron is an essential component of the proteins
involved in oxygen transport (Dalman, 1986), cell growth and differentiation
(Andrews, 1999).
61
Phosphorus Content
The phosphorus content of raw beef as reported by Lawrie(1991) is about
276mg/100g.The phosphorus content of the burgers as shown in table 13 are
lower than this value. This suggests that the inclusion of mushroom in
hamburgers reduced the phosphorus content of hamburgers, indicating that the
phosphorus content of mushroom is lower than that of beef. The reduction in
phosphorus content is attributed to dilution effect. An illustration of this
observation is found with burger samples made from ribeye muscle in which the
sample without mushroom had 122.25+1.38mg/100g,which was reduced to
80.99+1.04mg/100g on replacement of beef with up to 60% mushroom. Similar
trend was observed with the muscle of round and chuck muscle burgers.
The phosphorus content of ribeye and muscle of round samples; and
ribeye and chucks samples without mushroom respectively were found to be
statistically (P>0.05) the same. However, muscle of round and chuck burger
samples without mushroom showed significant difference (P<0.05). Also burger
samples without mushroom were found to be statistically different (P<0.05)
from burger samples with mushroom. At 20% level of mushroom the
phosphorus content of all the burger samples, and muscle of round burger
sample with 40% mushroom were not significantly different (P>0.05). At 40%
level of mushroom, there was no significant difference (P>0.05) in the
phosphorus content of ribeye and chuck burger samples. All the burger samples
with 60% mushroom differed significantly (P<0.05) from one another in their
phosphorus content. Muscle of round burger sample without mushroom had the
highest (124.62 ± 0.07mg/100g) phosphorus content. Among burger samples
with mushroom, muscle of round burger sample with 20% mushroom had the
highest (112.63 ± 0.86 mg /100g) phosphorus content, while ribeye sample with
60% mushroom had the lowest (80.99 ± 1.04mg /100g) phosphorus content.
62
The RDA for phosphorus according to Diet and Fitness Today (2010 a);
and Insel et al (2006) is 700mg. A serving size of one sandwich contains 175mg
phosphorus (Nutrition Factsheets, 2010 a), equivalent to 25% of the DV for
phosphorus. Cattlemens Beef Board and National Cattlemens Beef Association
(2006) reported that 85g serving of lean beef contributes 20% of the DV of
phosphorus. All the burgers (with and without mushroom) were found from this
study to have DVs above 10% hence good sources of phosphorus. The DV of
burgers without mushroom was found to be18% (average) while the DVs of
burgers with 20%, 40% and 60% mushroom were found to be 16%, 15% and
13% respectively. With the accompaniments and bun the phosphorus content of
the ultimate sandwich could still increase.
Zinc Content
The zinc content of raw beef is reported to be about 4.3mg/100g. The
zinc content of burger samples without mushroom irrespective of muscle cuts
was observed to be higher than this value. This can be attributed to
concentration effect. However at the addition of mushroom to the beef burgers,
the zinc content was lowered, suggesting that mushroom has less zinc content
compared with beef. Hence, as the quantity of mushroom was increased the
zinc content of burgers also reduced. This observation is illustrated with ribeye
muscle in which the zinc content of sample without mushroom was
5.25mg/100g, but which reduced to 2.09mg/100g as beef was replaced with
mushroom up to 60%. Similar trend has been observed for the burgers made
from the muscle of round and chuck muscle as well.
At 20% level of mushroom, the zinc content of ribeye and muscle of
round burger samples were not significantly different (P > 0.05) but differed
significantly (P < 0.05) from all other samples (Table 13). It was also observed
that all the other burger samples differed significantly (P<0.05) both without
and at the various levels of mushroom inclusion. Chuck burger sample without
63
mushroom had the highest (6.36±0.00mg/100g) zinc content. Among burger
samples with mushroom chuck sample with 20% mushroom was found to have
the highest (5.41 ± 0.00mg/100g) zinc content. While ribeye burger sample
with 60% mushroom had the lowest (2.09 ± 0.02 mg/100g) content. The RDA
for zinc for males (25 - 40years) is 11mg (Diet and Fitness Today, 2010 a;
Insel et al, 2006). The zinc content of one serving size (137g) of burger
sandwich according to Nutrition Factsheets (2010 a) is 4.11mg, corresponding
to 37% of the DV for zinc. On the other hand, Eating Well (2010) reported a
DV of zinc of 20% for a 90/10 ration of meat/mushroom burger. Cattlemens
Beef Board and National Cattlemens Beef Association (2006) reported that a
serving size of 85g lean beef contributes 38% of the DV of zinc. The DVs for
all the burgers (with and without mushroom) were found from this study to be
above 18%. The average DVs for the burgers without mushroom and with
20% mushroom are 54% and 41% respectively. These are higher than values
reported by Nutrition Factsheets (2010), Eating Well (2010) and Cattlemens
Beef Board and National Cattlemens Beef Association (2006). The
contribution of burgers with 40% and 60% mushroom to the DV of zinc was
found to be 33% and 19% respectively. According to Arpita (2009), zinc is
mostly needed to build the body’s immune system.
Calcium Content
Raw beef contains 5.4mg/100g calcium (Lawrie 1991).The calcium
content of burger samples observed in this study is higher than what is reported
for raw beef. This may be attributed to concentration during processing.
However, on inclusion of mushroom, the calcium content was reduced,
probably due to dilution effect. This observation is illustrated with burger
samples from ribeye muscle without mushroom which contains 25.00 ± 0.001
mg/100g calcium, but which on addition of up to 60% mushroom, the calcium
64
content decreased to 18.00 ± 0.001 mg/100g. Similar trend was observed with
burgers from muscle of round and chuck muscle.
The calcium content of burger samples without mushroom differed
significantly (P<0.05) from one another. This has been attributed to anatomical
differences. Chuck burger sample without mushroom and muscle of round
sample with 20% mushroom showed no significant difference (P>0.5) in their
calcium content, while all the burger samples without mushroom differed
significantly (P<0.05) from all other samples with mushroom. At 20% level of
mushroom, ribeye and muscle of round burger samples differed significantly
(P<0.5) in their calcium content, while ribeye and chuck burger samples were
found to be statistically the same (P>0.05). At 40% level of mushroom ribeye
and muscle of round; and ribeye and chuck burger samples were respectively
found to be statistically the same (P>0.05). However, muscle of round and
chuck samples differed significantly in calcium content at the same level of
mushroom. At 60% level of mushroom all the burger samples did not exhibit
significant differences (P > 0.05) in calcium content. Among burger samples
without mushroom, muscle of round sample was found to have the highest (27 ±
0.001 mg/100g) calcium content. Among burger samples with mushroom,
muscle of round burger with 20% mushroom had the highest (22 ± 0.001
mg/100g) calcium content while muscle of round samples with 60%, and chuck
samples with 40% and 60% mushroom respectively had the lowest (17 ± 0.001
mg/100g) calcium content.
The calcium content of mushroom and meat is reportedly low (Anderson
and Fellers, 1942; Lawrie, 1991, Varnam and Sutherland, 1995, Pearson and
Gillet, 1996) respectively, hence the observed low content of calcium in this
study. The RDA for calcium is 1000 mg (Diet and Fitness Today, 2010 a),
though the RDA is not strictly established hence adequate intake is
recommended. A serving size of one sandwich (137g) provides 7% of the DV of
calcium (Nutrition Factsheets, 2010 a). The study showed that the DVs of all
65
the burgers (with and without mushroom) were lower than that reported by
Nutrition Factsheets (2010 a), invariably because of the accompaniments and
bun used in the sandwich. The DV for burgers without mushroom was shown to
be 3%. The Dvs for burgers with 20%, 40%, 60% mushroom were 2%
respectively.
Sodium Content
Fresh beef reportedly contains 69 mg/100g sodium (Lawrie 1991). Fresh
mushroom on the other hand contains 27mg/100g sodium (Allan 2010). The
sodium content of burger samples observed in this study is higher than these
values. This might still be attributed to concentration during processing. The
inclusion of mushroom caused the sodium content to decrease. This observation
is illustrated by ribeye sample without mushroom which contains 121.00
mg/100g, but upon replacement of meat with up to 60% mushroom the sodium
content decreased to 86.00mg/100g. The trend was observed to be similar for
burgers from muscle of round and chuck muscle respectively.
Burger samples without mushroom, as well as ribeye burger sample with
20% were found to be statistically the same (P > 0.05), but significantly
different (P < 0.05) from all other samples in sodium content. At 20% level of
mushroom, the burger samples were significantly different (P<0.05) from
burgers at various levels of mushroom. At 60% level of mushroom ribeye and
muscle of round burger samples were found to be statistically the same (P>
0.05). At 40% level of mushroom, the burger samples exhibited significant
differences (P < 0.05). Round burger sample without mushroom showed the
highest (152 ± 0.001 mg/100g) content of sodium. Among the burger samples
with mushroom ribeye sample with 20% mushroom and muscle of round burger
sample with 60% mushroom had the highest (113
± 0.004 mg/100g) and lowest (81 ± 0.001 mg/100g) sodium content
respectively.
66
The RDA for sodium according to Diet and Fitness Today (2010 a) is
1.5g, though adequate intake is recommended as no RDA can be established. A
serving size of one sandwich (137g) contains 474mg sodium (Nutrition
Factsheets, 2010 a), corresponding to 32% of the DV for sodium. Eating Well
(2010) also reported that a 90/10 ration of meat/mushroom burger contains
436mg sodium, equivalent to 29% of the DV for sodium. The DVs for all the
burgers in this study were observed to be lower than 10% of the RDA for
sodium. The DV for the burgers without mushroom is found to be 9% (average)
of the RDA for sodium. The DVs for burgers with 20%, 40% and 60%
mushroom were 7%, 6%, 6% of the RDA for sodium. Oyster mushroom
content of 27mg sodium (according to Allan, 2010) represents 1% of the daily
value of sodium. The low sodium content is of health benefit; hence Arpita
(2009) reported that the minimal sodium content makes mushroom suitable for
people suffering from high blood pressure. The inclusion of mushroom
therefore improves the health value of hamburger for people suffering from high
blood pressure and cardiovascular diseases.
Potassium Content
The potassium content observed in this study is higher than what is
reported for fresh beef. Fresh beef contains 334 mg/100g potassium. The
observed higher content of potassium is attributed to concentration during
processing. It is observed that the inclusion of mushroom caused the potassium
content to decrease. This observation is illustrated by burger sample from ribeye
muscle without mushroom which contains 469.00 ± 0.003 mg/100g, but which
upon replacement of beef with 60% mushroom decrease to 426 ± 0.008
mg/100g. This trend was similarly observed for burgers from muscle of round
and chuck muscle respectively.
Table 13 showed that no significant difference (P>0.05) was found among
all the burger samples in potassium content irrespective of muscle cuts and
67
levels of mushroom inclusion. However, ribeye burger sample without
mushroom showed the highest (469 ± 0.003 mg/100g) potassium content.
Among samples with mushroom ribeye sample with 20% and 60% mushroom
had the highest (466 ± 0.023 mg/100g) and lowest (426 ± 0.008 mg/100g)
potassium content respectively.
The RDA for potassium is 4.7g (Diet and Fitness Today, 2010 a; Insel el al,
2006), however adequate intake is recommended as no fixed RDA is established
for potassium. A serving size of one sandwich (137g), according to Nutrition
Factsheets (2010 a) contains 267mg potassium. This value corresponds to 6% of
the DV of potassium reported by Diet and Fitness Today, (2010 a) and Insel, et
al (2006). Eating Well (2010) reported that a 90/10 nation of meat/mushroom
burger contains 504mg potassium. This value corresponds to 11% of the DV for
potassium. The DVs of burgers without mushroom and with 20% mushroom
were found from this study to be 10% respectively, while the burgers with 40%
and 60% mushroom contain 9% respectively of the DV of potassium. The Dvs
of all the burgers in this study, though slightly lower than that reported for a
90/10 ration of meat/mushroom burger were found to be higher than the DV of
a serving size (137g) of burger sandwich reported by Nutrition Factsheets (2010
a).
Mushrooms are reportedly rich in potassium and copper (Arpita, 2009;
Genccelep et al, 2009; Anderson and Fellers, 1942; and Chang and Tu, 1978).
Lawrie (1991) also reported high content of potassium but low content of
copper in meat. Potassium and copper are essential for cardiovascular health;
including mushroom in hamburger therefore enhances the health value of
hamburger. Mushroom is reported (Graiones, 2001) to help thin the blood and
consequently reduce the rate of heart disease. This could be due to the reported
content of potassium and copper in mushroom
68
4.3 Contribution of mushroom to the vitamin composition of hamburger
The vitamin content of the burger products is as shown in table 14. From
the table it is seen that the addition of mushroom caused a general increase in
vitamin C content and decrease in vitamin A, thiamin, riboflavin and niacin
content.
Vitamin C Content
The vitamin C content of the products was higher than what is known for
raw beef muscles. The inclusion of mushroom increased the vitamin C content.
This is illustrated by burger sample from ribeye muscle without mushroom
which contained 2.39 ± 0.02mg/100g and the same muscle with 60% mushroom
which contained 2.76 ± 0.00mg/100g vitamin C. Similar trend was observed for
muscle of round and chuck muscle.
Table 14 shows that vitamin C content of burger samples without
mushroom differed significantly (P < 0.05) between muscles.
Table 15: Effect of mushroom inclusion on the vitamin composition of hamburger*
Muscle
cut
Level of
mushroom
(%)
Vitamin C
(mg/100g)
Vitamin A
(µg/100g)
Thiamine
(mg/100g)
Riboflavin
(mg/100g)
Niacin
(mg/100g)
Ribeye 0 2.39 ± 0.02a
10.25 ± 0.00k
.089 ± .004f
.271 ± .013ef
2.13 ± 0.00a
20 2.81 ±0.07
d 8.91 ± 0.00
h .089 ± .001
f .217 ± .006
d 2.10 ± 0.00
a
40 2.76 ± 0.07d
8.67 ± 0.00f
.073 ± 0.00d
.184 ± .023bc
2.01 ± 0.00a
60 2.76 ± 0.00d 4.75 ± 0.00
c .045 ± 0.004
a .139 ± .018
a 1.91 ± 0.01
a
Round 0 2.51 ± 0.01b 9.54 ± 0.00
i .094 ± 0.004
g .290 ± .018
f 2.22 ± 0.00
a
20 2.76 ± 0.07d 7.71 ± 0.01
e .078 ± .001
e .253 ± .011
e 2.15 ± 0.00
a
40 2.75 ± 0.00d 6.48±0.00
d .070 ± .001
d .166 ± .011
ab 2.12 ± 0.00
a
60 2.71 ±0.07cd
2.88 ± 0.00a
.065 ± .001b
.164 ± 0.011ab
1.91 ± 0.00a
Chuck 0 2.64 ±0.07c
10.78 ± 0.00L
.093 ± .001g
.261 ± .001e
2.17 ± 0.00a
20 2.77 ± 0.01d
9.73 ± 0.00i
.086 ± .001f
.211 ± 0.013cd
2.11 ± 0.00a
40 2.75 ± 0.00d
8.74 ± 0.05g
.073 ± .001d
.211 ± 0.00cd
1.93 ± 0.00a
60 2.76 ± 0.01d
4.70 ± 0.01b
.053 ± .001c
.163 ± 0.11ab
1.88 ± 0.00a
*Values are in means ± SD and means with the same superscript in the same column are not
significantly different (P> 0.05).
69
Because meat is virtually devoid of vitamin C (Lawrie, 1991), the
observed vitamin C content of burger samples without mushroom must have
resulted from the constituents of the recipe. Nonetheless the contribution of this
mushroom to the vitamin C content of the burgers with mushroom is very low
and did not show progression with mushroom levels. The vitamin C content of
all the burger samples with mushroom irrespective of mushroom levels was
found not to be statistically different (P > 0.05). Ribeye burger sample with
20% mushroom had the highest (2.81 ± 0.07 mg/100g) content of vitamin C,
while burger sample from the muscle of round with 60%mushroom was the
least (2.71±0.07mg/100g). Among samples without mushroom chuck and ribeye
samples had the highest (2.64 ± 0.07 mg/100g) and lowest (2.39 ± 0.02
mg/100g) vitamin C content respectively.
The RDA for vitamin C is 90mg (Diet and Fitness Today, 2010 a; Insel et
al, 2006). A serving size of one sandwich (137g) and beef patty (100g) was
observed (Nutrition Factsheets, 2010 a; USDA, 2010) respectively to contain no
vitamin C. However, according to Eating Well (2010) a 90/10 ration of
meat/mushroom burger was found to contain 15% of the DV of vitamin C. This
might have been due to the use of mushroom such as Agaricus bisporos with
high content (81.9mg/100g dwb) of vitamin C, and the vegetables used in the
toppings. All the burgers (with and without mushroom) studied were found to
contribute about 3% of the DV of vitamin C.
Vitamin A Content
Muscle tissue is generally poor in fat soluble vitamins (Lawrie 1991;
Pearson and Gillet, 1996). The vitamin A content observed in this study is
higher than what is known for raw beef. The high vitamin A content of burger
samples without mushroom might have derived from the high fat content of the
muscles used and possibly that beef absorbed and retained more of the oil used
in frying. The inclusion of mushroom reduced the vitamin A content of beef
70
burgers. Mushroom is not reported as a source of vitamin A; hence the
reduction of vitamin A content as mushroom is increased. This is illustrated by
burger sample from ribeye muscle without mushroom which contained 10.25 ±
0.00µg /100mg vitamin A, but which reduced to 4.75 ±0.00µg/100g as
mushroom level increased up to 60%. Similar trend was observed for the
muscle of round and chuck muscle samples.
From table 14 the vitamin A content of burger samples without
mushroom was found to be significantly different (P < 0.05) among muscle
cuts. Chuck sample with 20% mushroom, was found to be statistically the same
(P > 0.05) with muscle of round burger without mushroom. All the burger
samples were found to differ significantly (P < 0.05) at the various levels of
mushroom. Chuck burger sample without mushroom showed the highest
(10.78±0.00 µg/100g) content of vitamin A. Among burger samples with
mushroom, chuck sample with 20% mushroom and muscle of round sample
with 60% mushroom had the highest (9.73 ± 0.00 µg/100g) and lowest (2.88 ±
0.00 µg/100g) vitamin A content respectively.
The vitamin A content (10.2µg, average) of burgers without mushroom
observed in this study is found to be similar to that (11µg) reported for beef
patty (USDA, 2010), nevertheless both vitamin A content contribute 0% to the
DV (900 µg, according to Diet and Fitness Today, 2010 a;and Insel, et al 2006)
of vitamin A. However, including vegetables as carrot, spinach, kale, beet
greens, broccoli, etc which are considered good sources of vitamin A (Medline
Plus Medical Encyclopedia, 2010) among the accompaniments in the burger
sandwich might improve the vitamin A content of burgers.
Thiamin Content
The thiamin content of raw beef as reported by Lawrie (1991) is
0.07mg/100g.The thiamin content of burgers without mushroom was found to
be higher than this value. This might be due to concentration sequel to
71
processing. The inclusion of mushroom reduced the thiamin content of
hamburgers. This is illustrated by burger sample made from ribeye muscle
without mushroom which contained 0.089 ± 0.004mg/100g, but on replacement
of beef with up to 60% mushroom, the thiamin content decreased to 0.045 ±
0.004mg/100g.This trend is similarly observed for burgers from muscle of
round and chuck muscle.
The thiamin content of muscle of round and chuck burger samples
without mushroom (table 14), did not differ significantly (P>0.05), but both
differed significantly (P < 0.05) from ribeye sample without mushroom. At 20%
level of mushroom ribeye and chuck burger samples were statistically different
(P < 0.05) from muscle of round sample. At 40% level of mushroom no
significant difference (P>0.05) was observed among burger samples in thiamin
content. At 60% level of mushroom, all the burger samples were found to differ
significantly (P<0.05). The highest (0.094 ± 0.004 mg/100g) thiamin content
was observed in muscle of round burger sample without mushroom. Among
burger samples with mushroom, the highest (0.094 ± 0.004 mg/100g) and
lowest (0.045 ± 0.004 mg/100g) content of thiamin was found in muscle of
round and ribeye burger samples with 20% and 60% mushroom respectively.
The thiamin contents of all the burgers (with and without mushroom) in
this study are observed to be higher than what (0.051mg - 3% DV) was reported
(USDA, 2010) for a serving size (100g) of one beef patty. According to USDA
(2005) a serving size of 85g lean beef contributes 37% of the DV of thiamin. A
serving size of one sandwich (137g) contains 0.288mg (a DV of 24%) thiamin
(Nutrition Factsheets, 2010 a). These are much higher than the values observed
in this study. Fresh oyster mushroom reportedly (Organic Mushroom Growing
Kits, 2010) contains 0.5mg of thiamin. The RDA of thiamin reported by Diet
and Fitness Today (2010 a) is 1.2mg. All the burgers in this study contribute
less than 10% of the DV of thiamin. The low thiamin content could have arisen
72
from processing losses (leaching, heating, etc), and the high proportion of fat in
the muscles used. The burgers without mushroom contribute 8%(average) to the
DV of thiamin while the burgers with 20%,40% and 60% mushroom contribute
7%,6% and 5% (average) respectively. The vegetables used as accompaniments
could have contributed more to the thiamin content of burger sandwich reported
by Nutrition Factsheets (2010).
Riboflavin Content
Raw beef is reported to contain about 0.2mg /100g riboflavin. It is
observed from this study, that the riboflavin content of burgers without
mushroom was higher than this value. This might still be due to concentration.
However, the addition of mushroom reduced the riboflavin content of burgers,
implying that mushroom contains less riboflavin compared to beef. The reduced
riboflavin content is due to dilution effect, caused by mushroom. This is
illustrated by burger sample made from ribeye muscle without mushroom which
contains 0.271± 0.013mg/100g and the same muscle with 60% mushroom
which contains 0.139± 0.018mg/100g riboflavin. Similar trend was observed for
burgers from muscle of round and chuck muscle.
Ribeye and muscle of round as well as muscle of round and chuck burger
samples without mushroom respectively were found to be statistically the same
(P>0.05), though ribeye and chuck samples without mushroom differed
significantly (P < 0.05). It was also observed that muscle of round sample with
20% mushroom did not exhibit significant difference (P>0.05) from chuck
sample without mushroom. None the less, at 20% level of mushroom ribeye and
chuck samples were statistically the same (P>0.05). At 40% level of mushroom
no significant difference (P>0.05) was found between ribeye and muscle of
round samples as well as ribeye and chuck samples respectively. At 60% level
of mushroom, no significant difference (P > 0.05) was observed among the
burger samples in riboflavin content.
73
Muscle of round sample without mushroom had the highest (.290±
0.014mg/100g) content of riboflavin. Among the burger samples with
mushroom, muscle of round sample with 20% mushroom and ribeye sample
with 60% mushroom had the highest (0.253 ± 0.011mg /100g) and lowest
(0.139 ± 0.018mg /100g) riboflavin content respectively.
The riboflavin content of the burger sample without mushroom, and with
20% mushroom as well as chuck sample with 40% mushroom was found to be
higher than that reported by Lawrie (1991) for beef. The DV of riboflavin
according to Diet and Fitness Today (2010 a); Insel et al, (2006) and Wikipedia
(2010) is 1.3mg. All the burger samples studied are found to contribute more
than 10% of the DV of riboflavin and compare favourably with a serving size
(85g) of lean beef, 137g sandwich, and 100g beef patty. A serving size of 85g
lean beef contributes 12% of the DV of riboflavin (USDA, 2005). A serving
size (137g) of one sandwich contains 0.288mg riboflavin (Nutrition Factsheets,
2010 a), corresponding to 22% of the DV. A serving size of 100g beef patty
contains 0.186mg riboflavin. The riboflavin content of oyster mushroom per
100g is 0.5mg (Organic Mushroom Growing Kits, 2010), equivalent to 35% of
the DV. The burgers without mushroom contribute 21% (average), while
burgers with 20%, 40% and 60% mushroom contribute 17%, 14% and 12%
(average) of the DV of riboflavin respectively.
Niacin Content
The niacin content of raw beef has been reported to be about 5.0mg/100g.
Organic mushroom Growing Kits (2010), on the other hand reported that fresh
oyster mushroom contains 10.9mg/100g niacin. It is however observed from
this study that the niacin content of the burger samples was lower than these
values. This could be attributed to processing losses, and the degree of fat
contained in the muscles used for this study. Still, the inclusion of mushroom
resulted in the reduction of niacin content of hamburgers. This might be
74
attributed to dilution effect. This observation is illustrated by burgers from
ribeye muscle without mushroom which contains 2.13±0.0mg/100g niacin, but
upon replacement of beef with 60% mushroom decreased to 1.91±0.01mg/100g.
Similar trend was observed for burgers made from muscle of round and chuck
muscle.
Table 14 shows that no significant difference (P>0.05) was observed in
the niacin content of all the burger samples. This result implies that meat and
mushroom, both according to literature report (Ikeme, (1990) Lawrie (1991),
USDA (2005)) are good sources of niacin complimented each other irrespective
of the level of mushroom inclusion in the niacin content of the burger samples.
Oyster mushroom content of niacin is reported to be up to 5 to 10 times higher
as compared to other vegetables. The niacin content of fresh oyster mushroom
reported by Organic Mushroom Growing Kits (2010) corresponds to 68% of the
DV of niacin. The RDA for niacin is 16mg (Diet and Fitness Today, 2010 a;
and Wikipedia, 2010). Foulds (2010) reported that cooked oyster mushroom
contains about 1/2 of the RDA of niacin. A serving size of 85g lean beef
contributes 17% of the DV of niacin per 100g. The burgers without mushroom
contribute on the average 14%, while the burgers with 20%, 40% and 60%
mushroom contribute 13%, 12% and 12% of the DV of niacin respectively. The
DVs of all the burger samples in this study are lower than that (17%) reported
(USDA, 2005) for a serving size (85g) of lean beef, but comparable with that
(14%) reported (USDA, 2010) for a 100g serving size of beef patty. The lower
DVs observed in this study compared with that reported for lean beef by USDA
(2005), could have been due to the fat content of the muscles used.
4.4 Contribution of mushroom to the physical characteristics of hamburger
Soluble Protein
Table 15 shows that the soluble protein content of hamburger samples
decreased gradually with increase in mushroom levels. The higher digestibility
75
of meat (94.97%) according to Varnan and Sutherland (1995) compared with
that of mushroom, (72 – 83%) according to Lintzel (1941). and Gray (1970)
could have accounted for the high soluble proteins in samples without
mushroom. The inclusion of mushroom reduced the protein solubility of
hamburgers. This observation is illustrated by burger sample from ribeye
muscle without mushroom which contains 42.82±0.31%, but upon replacement
of beef with 60% mushroom decreased to 30.63±0.24%. Similar trend was
observed for burger samples made from muscle of round and chuck muscle.
Table 16: Effect of mushroom inclusion on the physical characteristics of
hamburger
Muscle cuts % level of
mushroom
Soluble
proteins (%)*
pH Water activity
(aw)
Ribeye 0 42.82 ± 0.31h
5.45 ± 0.07 0.84
20 38.59 ± 0.18f
5.50 ± 0.14 0.89
40 34.90 ± 0.90d
5.55 ± 0.07 0.94
60 30.63 ± 0.24c
5.50 ± 0.00 0.85
Round 0 40.52±0.23g
5.40 ± 0.14 0.85
20 36.54± 1.15e
5.55 ± 0.21 0.89
40 30.15 ± 0.37c
5.45 ± 0.21 0.87
60 27.03 ± 0.01b
5.50 ± 0.42 0.88
Chuck 0 40.88 ± 0.29g
5.40 ± 0.14 0.86
20 36.73 ± 0.29e
5.65 ± 0.21 0.95
40 30.23 ± 0.10c
5.55 ± 0.21 0.96
60 26.05 ± 0.16a
5.60 ± 0.14 0.94
*Values are in means ± SD and means with the same superscripts in the same column are not
significantly different (P > 0.05).
The soluble protein content of muscle of round and chuck burger samples
were statistically the same (P > 0.05), but differed significantly (P<0.05) from
ribeye sample without mushroom. At 20% and 40% level of mushroom muscle
of round and chuck samples were not significantly different (P > 0.05)
76
respectively, yet differed significantly (P<0.05) from ribeye. At 60% level of
mushroom significant differences (P<0.05) existed among the burger samples.
Ribeye burger sample without mushroom had the highest (42.82 ± 0.31%)
soluble proteins. Among samples with mushroom ribeye sample with 20% and
chuck sample with 60% mushroom had the highest (38.59± 0.18%) and lowest
(26.05 ± 0.16%) soluble proteins respectively.
pH
Table 14 shows that all the burger samples were slightly acidic (pH ≤
5.65). It was generally observed that the pH values of burger samples without
mushroom were lower than those of burger samples with mushroom. There was
no regular pattern to indicate that increasing levels of mushroom caused any
progressive effect on pH of burger samples. However, muscle of round and
chuck burger samples without mushroom had the lowest pH (5.40 ± 0.42), while
muscle of round and chuck samples with 40% and 20% mushroom had the
highest pH (5.65 ± 0.14). The pH values were observed to be in the range of
optimum pH for most bacteria as reported by Banwart (1998).
Water activity (aw)
From table 15, it is observed that the water activity of burger samples
without mushroom was generally lower than those of samples with mushroom.
Inclusion of mushroom might have caused an increase in the water holding
capacity of hamburger. It was observed still that no specific pattern/trend could
be established to show the effect of increasing levels of mushroom on the water
activity of hamburger. The highest water activity (0.96) was observed with
chuck sample with 40% mushroom, while ribeye burger sample without
mushroom had the lowest water activity (0.84). In this range of water activities
all the burger samples are vulnerable to microbial activities, since according to
Potter and Kotchkiss (1995) most bacteria require an aw in the range of 0.90 –
1.0. According to Banwart (1998) a safe water activity level for storage is
77
usually considered to be 0.70 or less. The aw for all the samples in this study is
higher than this reported safe limit. However, a aw lower than 0.70 would make
the burgers too dry, tough and unpalatable.
4.5 Contribution of mushroom to the sensory qualities of hamburger.
4.5.1 Colour attributes of hamburger with and without mushroom
The colour of burger samples without mushroom was rated highest
among burgers from each muscle cuts. The inclusion of mushroom resulted in
decreased colour rating for all the burger samples. This observation is illustrated
by burger samples made from ribeye muscle which colour rating of 7.00±1.05,
reduced to 5.30±0.82 when beef was replaced with mushroom up to 60%. This
trend in colour rating is found to be similar for burger samples made from
muscle of round and chuck muscle.
From table 16, it is observed that no significant differences (P > 0.05)
existed in the colour of all but one (chuck burger with 20% mushroom,) of the
burger samples with mushroom irrespective of the level of mushroom.
78
Table 17: Effect of mushroom addition on the colour of hamburger*
Steak cuts % level of
mushroom
Score Description
Ribeye 0 7.00 ± 1.05de
Moderately liked
20 5.50 ± 1.29abc
Slightly liked
40 6.20 ± 1.23abcd
Slightly liked
60 5.30 ± 0.82abc
Neither liked nor disliked
Round 0 6.70 ± 1.89 cde
Moderately liked
20 5.40 ± 1.65abc
Neither liked nor disliked
40 5.10 ± 1.79a
Neither liked nor disliked
60 5.20 ± 1.135ab
Neither liked nor disliked
Chuck 0 7.90 ± 0.99e
Highly liked
20 6.60 ± 1.58bcde
Moderately liked
40 6.20 ± 0.92abcd
Slightly liked
60 6.02 ± 2.13a
Slightly liked
*Values are in means ± SD and means with the same superscripts are not significantly different
(P > 0.05).
The colour of all the burger samples without mushroom as well as the
chuck burger sample with 20% mushroom was not significantly different
(P > 0.05). Chuck burger sample without mushroom had the highest (7.90 ±
0.99) colour rating and was “highly liked”. Among samples with mushroom
chuck sample with 20% and muscle of round sample with 40% mushroom had
the highest (6.60 ± 1.58) and lowest (5.10 ± 1.79) colour ratings being
“moderately liked” and “neither liked nor disliked” respectively. Generally the
colour of the burger samples was rated good as no sample scored less than 5.00.
The table also revealed that the colour of all the chuck burger samples at the
various levels of mushroom was liked by the panellists and were rated higher,
compared to the other muscle cuts. The high fat content of chuck burger (Table
79
12)which could have as well been due to high marbling fat (intramuscular fat); a
quality parameter reported by Faustman (1994); and Varnan and Sutherland
(1995), to influence colour of meat, hence the high colour desirability of chuck
samples by panellists.
4.5.5 Contribution of mushroom to the texture of hamburger
The texture of burger samples without mushroom was rated highest
among burgers from each muscle cuts. The inclusion of mushroom resulted in
decreased texture rating for all the burger samples. This observation is
illustrated by burger samples made from ribeye muscle which texture rating of
7.10±1.20, reduced to 4.30±1.64 upon replacement of beef with mushroom up
to 60%. This trend in texture rating is found to be similar for burger samples
made from muscle of round and chuck muscle.
Table 17 shows that Chuck burger samples with mushroom generally
scored higher and were better liked compared with the other samples with
mushroom. The texture rating for all the burger samples without mushroom,
ribeye sample with 20% and chuck sample with 20% and 40% mushroom
respectively were not significantly different (P>0.05). The texture rating for
ribeye samples with 40% and 60%, muscle of round samples with 20%, 40%
and 60%, and chuck sample with 60% mushroom respectively were observed to
be statistically the same (P>0.05). Muscle of round and chuck burger samples
without mushrooms were “highly liked” by the panellists, with texture rating of
7.80±0.79 and 7.70±0.68 respectively. Among the burger samples with
mushroom, the chuck sample with 20% mushroom had the highest score
(6.50±1.65) being “liked moderately”. Ribeye burger sample with 60%
mushroom had the lowest score (4.30±1.64) for texture and was “slightly
disliked” by the panellists.
80
Table 18: Effect of mushroom addition on texture of hamburger*
Muscle
cuts
% level of
mushroom
Score Description
Ribeye 0 7.10 ± 1.20de
Moderately liked
20 6.30 ± 1.34bcde
Slightly liked
40 5.00 ± 2.31abc
Neither liked nor disliked
60 4.30 ± 1.64a
Slightly disliked
Round 0 7.80 ± 0.79e
Highly liked
20 5.70 ± 1.25abcd
Slightly liked
40 5.00 ± 1.83abc
Neither liked nor disliked
60 4.80 ± 2.144ab
Neither liked nor disliked
Chuck 0 7.70 ± 0.68e
Highly liked
20 6.50 ± 1.65cde
Moderately liked
40 6.30 ± 1.64bcde
Slightly liked
60 5.70 ± 1.89abcd
Slightly liked
*Values are in means ± SD and means with the same superscript in the same column are not
significantly different (P > 0.05).
The appreciable texture of all (but ribeye sample with 60% mushroom) is
in agreement with Bano et al (2000) and Doug (2008) reports, which described
mushroom, as having acceptable biting properties and meaty texture
respectively. The good appraisal of the texture can be related to juiciness
contributed by fat (Varnan and Sutherland (1995), Malony (1999), and USDA
(2005)).
4.5.6 Contribution of mushroom to the odour/aroma of hamburger
The aroma of burger samples without mushroom was rated highest
among burgers from each muscle cuts. The inclusion of mushroom resulted in
decreased aroma rating for all the burger samples as mushroom level increased.
This observation is illustrated by burger samples made from ribeye muscle
81
which aroma rating of 7.20±0.92, reduced to 4.60±1.27 upon replacement of
beef with mushroom up to 60%. This trend in aroma rating is found to be
similar for burger samples made from muscle of round and chuck muscle.
The aroma scores for chuck burger samples were observed to be
generally higher than those of ribeye and muscle of round at all levels of
mushroom and without mushroom.
Table 19: Effect of mushroom addition on the aroma/odour of hamburger*
Muscle
cuts
% level of
mushroom
Score Description
Ribeye 0 7.20 ± 0.92ef
Moderately liked
20 5.90 ± 1.29bcd
Slightly liked
40 4.80 ± 1.14ab
Neither liked nor disliked
60 4.60 ± 1.27a
Neither liked nor disliked
Round 0 7.00 ± 0.94def
Moderately liked
20 6.20 ± 0.92cde
Slightly liked
40 6.20 ± 1.14cde
Slightly liked
60 5.10 ± 1.45abc
Neither liked nor disliked
Chuck 0 7.70 ± 0.68f
Highly liked
20 7.20 ± 1.65ef
Moderately liked
40 6.60 ± 1.64def
Moderately liked
60 5.40 ± 1.89abc
Neither liked nor disliked
*Values are in means ± SD and means with the same superscript in the same column are not
significantly different (P > 0.05).
All the burger samples without mushroom as well as chuck samples with
20%, and 40% mushroom were found to be statistically the same (P > 0.05). It
was also observed that the chuck sample without mushroom was “highly liked”
(7.70 ± 1.25) while ribeye and muscle of round samples without mushroom and
muscle of round samples with 20% and 40% mushroom and having 7.20 ± 0.92,
7.00±0.94, 7.20±1.03 and 6.60±0.70 respectively were considered “moderately
liked” by the panellists.
82
At 20% level of mushroom, no significant differences (P > 0.05) were
observed between ribeye and muscle of round samples, and muscle of round
and chuck samples respectively. At 40% level of mushroom ribeye burger
sample differed significantly (P < 0.05) from muscle of round and chuck
samples in aroma scores. All the burger samples with 60% mushroom did not
show significant difference (P>0.05) in aroma. Ribeye sample with 20% and
muscle of round sample with 20% and 40% mushroom were “slightly liked”
having scored 5.90 ± 1.29, 6.20±0.92 and 6.20±1.14 respectively. A favourable
competition was observed between ribeye and muscle of round samples without
mushroom and chuck samples with 20% and 40% mushroom respectively. The
aroma of ribeye sample with 40% and all samples with 60% mushroom were
describes as “neither liked nor disliked” having scored 4.80±1.14, 4.60±1.27,
5.10±1.45 and 5.40±1.58 respectively. Notwithstanding the degree of likeness,
the aroma rating of all the burger samples was generally high in accordance
with Bahl (2000), and Chong et al, (2007) in respect of the use of fungi to scent
sources and soups; and the richness of mushroom aroma respectively.
4.5.7 Effect of mushroom inclusion on the taste of hamburger
The panel assessment of the taste of the burger samples shows that the
taste decreased with increase in mushroom levels for all the muscle cuts (Table
19). The taste of burger samples without mushroom was rated highest among
burgers from each muscle cuts. The inclusion of mushroom resulted in
decreased taste rating for all the burger samples. This observation is illustrated
by burger samples made from ribeye muscle which taste rating of 6.80±1.89,
reduced to 3.80±2.68 upon replacement of beef with mushroom up to 60%.
Similar trend in taste rating was observed for burger samples made from muscle
of round and chuck muscle.
83
All the burger samples without mushroom as well as ribeye sample with
20% and chuck samples with 20%, 40% mushroom were found to be
statistically the same (P>0.05) in taste and were all “liked moderately”.
Table 20: Taste of hamburger with and without mushroom*
Muscle
cuts
% level of
mushroom
Score Description
Ribeye 0 6.80 ± 1.89c
Moderately liked
20 6.50 ± 1.71c
Moderately liked
40 4.40 ± 2.71ab
Slightly disliked
60 3.80 ± 2.68a
Slightly disliked
Round 0 7.10 ± 2.68c
Moderately liked
20 5.10 ± 1.84ab
Neither liked nor disliked
40 4.41 ± 1.29ab
Slightly disliked
60 4.10 ± 2.15a
Slightly disliked
Chuck 0 7.30 ± 1.57c
Moderately liked
20 6.70 ± 1.58c
Moderately liked
40 6.50 ± 0.85bc
Moderately liked
60 5.00 ± 2.20ab
Neither liked nor disliked
*Values are in means ±SD and means with the same superscripts in the same column are not
significantly different (P > 0.05).
All the other samples were also found to be statistically the same
(P>0.05) in taste irrespective of mushroom levels. Chuck burger sample without
mushroom was found to have the highest (7.30±1.57) rating. The appreciable
taste of burger samples without mushroom could be due to the fat content and
contribution of fat to taste of meat in accordance with Faustman (1994) and
Malony (1999). The decrease in taste with increase in mushroom levels could
therefore be attributed to the decrease in fat content as mushroom levels
84
increased. The chuck burger samples were still rated higher than the other
muscles at the various levels of mushroom. The higher fat content of chuck
samples (table 12) compared with ribeye and muscle of round samples at the
various levels of mushroom could have accounted for the higher taste of chuck
samples. Among the burger samples with mushroom chuck sample with 20%
mushroom rated highest (6.70±1.58) for taste. Ribeye and muscle of round
samples with 40% and 60% mushroom respectively were “slightly disliked” by
the panellists, having scored 4.40±2.71 and 3.80±2.68 as well as 4.41±1.29 and
4.10±2.15 respectively. The mushroom flavour though described as delightful
(Moore, 2003) and acceptable (Bano, et al, 1963) is uniquely different from
meat flavour, more so hamburger is a noted meat product, hence the observed
decrease in the taste/flavour of burgers with mushroom.
4.5.5 Contribution of mushroom to the general acceptability of hamburger
From Table 20, it is seen that the general acceptability of hamburger
samples decreased with increased level of mushroom. Burger samples without
mushroom were rated highest among burgers from each muscle cuts. The
inclusion of mushroom resulted in decreased rating for the general acceptability
of all the burger samples. This observation is illustrated by burger samples
made from ribeye muscle which acceptability rating of 7.10±1.29, reduced to
3.50±1.78 upon replacement of beef with mushroom up to 60%. Similar trend in
acceptability rating was observed for burger samples made from muscle of
round and chuck muscle.
Chuck burger samples were found to be generally more acceptable than
ribeye and muscle of round samples. All the burger samples without mushroom
as well as chuck sample with 20% mushroom were not significantly different (P
> 0.05). At 20% and 40% level of mushroom all the burger samples were found
to be statistically the same (P>0.05) in their acceptability. Chuck burger sample
without mushroom was scored highest (8.10±0.99) and was described as
85
“highly acceptable”. This result agrees with Wikipedia (2005) in respect of
chuck as being the most popular choice for hamburger due to its richness of
flavour and balance of meat and fat.
Table 21: General acceptability of hamburger with and without mushroom*
Muscle
cuts
% level of
mushroom
Score Description
Ribeye 0 7.10 ± 1.29def
Moderately acceptable
20 6.10 ± 2.13bcde
Slightly acceptable
40 5.50 ± 1.96bcd
Slightly acceptable
60 3.50 ± 1.78a
Slightly unacceptable
Round 0 7.60 ± 1.08ef
Highly acceptable
20 5.60 ± 1.71bcd
Slightly acceptable
40 5.20 ± 1.87bc
Neither acceptable nor
unacceptable
60 4.90 ± 2.38ab
Neither acceptable nor
unacceptable
Chuck 0 8.10 ± 1.00f
Highly acceptable
20 6.80 ± 1.23cdef
Moderately acceptable
40 6.40 ± 1.35bcde
Slightly acceptable
60 5.30 ± 1.77bc
Neither acceptable nor
unacceptable *Values are in means ± SD and means with the same superscript in the same column are not
significantly different (P>0.05).
At 60% level of mushroom ribeye and muscle of round as well as muscle
of round and chuck samples were observed to be statistically the same (P>0.05)
respectively. However, ribeye and chuck samples with 60% mushroom were
found to be significantly different (P <0.05). Among burger samples with
mushroom chuck sample with 20% mushroom was scored highest (6.80±1.23),
being “moderately acceptable”.
86
4.6 Contribution of mushroom to the quality changes of hamburger during
storage
4.6.1 Changes in pH of hamburger samples with and without mushroom
during storage
The changes in pH of burger samples during storage was observed to be
very minimal as all the samples had slightly lower pH on the last day of storage
(figure 1, 2 and 3). The initial pH ranged between 5.8 and 5.4 to 5.6 and 5.4 on
the last day of storage. Muscle of round sample with 60% mushroom had the
highest initial (5.80±0.42) and final (5.60±0.28) pH during storage. Chuck
sample without mushroom which had the lowest initial (5.40±0.14) pH, had a
pH of 5.45±0.21 on the last day. The changes in pH during storage did not
follow any distinct regular pattern to be attributed to the inclusion of mushroom
or the differences in muscle cuts.
87
88
89
90
4.6.2 Rates of change of pH of burger samples during storage
The rate of change of pH of burger samples during storage is shown in
table 21. Table 21 shows that the rate of changes of pH of muscle of round
burger sample with 20% mushroom was lowest (0.00), while ribeye samples
with 0%, 40%; muscle of round with 60%; and chuck sample with 0%
mushroom respectively had the highest rate (0.025) of changes of pH during
storage.
Table 22: Rates of change in pH of burger samples during storage
Muscle cuts % of mushroom Change in pH/Day
Ribeye 0 0.025
20 0.013
40 0.025
60 0.013
Round 0 0.019
20 0.00
40 0.019
60 0.025
Chuck 0 0.025
20 0.019
40 0.013
60 0.013
Though the chuck burger samples showed decrease in rate of pH changes,
ribeye and muscle of round samples did not show any specific trend to imply
the effect of mushroom inclusion on the rate of pH changes.
91
4.6.3 Changes in water activity (Aw) of burger samples during storage
The water activities of burger samples at commencement of storage
ranged from 0.84 and 0.96(Table15). A gradual decrease in water activities of
all burger samples was observed throughout the period of storage (figure 4, 5
and 6). The decrease in water activity indicated a corresponding loss of moisture
from the samples during storage. The water activities of burger samples without
mushroom were generally lower; especially up to the fourth day of storage
(figure 4, 5 and 6). Burger samples with mushroom had higher initial water
activities, up to the fourth day of storage. The water activities of burger samples
on the last day of storage ranged between 0.53 and 0.60. Though burger samples
with mushroom had higher initial water activities, the trend was not generally
the same on the last day. At the end of the storage period the burger samples
were found to be too dry and tough.
92
93
94
95
4.6.4 Rates of changes of water activities of burger samples during storage
Table 22 shows the rates of changes of water activity of burgers samples
during storage. The rates of changes in water activities of chuck burger samples
were generally higher, except for ribeye burger sample with 40% mushroom
which exhibited the highest rate (0.054).
Table 23: Rates of changes of water activities of burger samples during
storage.
Muscle cut % of mushroom Change in Aw/Day
Ribeye 0 0.038
20 0.036
40 0.054
60 0.036
Round 0 0.036
20 0.039
40 0.030
60 0.040
Chuck 0 0.040
20 0.053
40 0.049
60 0.046
Incidentally, it was observed that muscle of round sample with 40%
mushroom had the lowest rate (0.030) of changes in water activities. A critical
observation of table 22 still showed that no regular pattern could be established
to suggest the effect of mushroom inclusion on the rates of changes of water
activities of the burger samples during storage.
96
4.6.5 Changes in total viable count of burger samples during storage
From table 23, it is observed that muscle of round and chuck burger
samples with mushroom had higher total viable count of micro organisms than
the samples without mushroom throughout the storage period. However, ribeye
burger sample without mushroom showed initial higher total viable counts than
samples with mushroom for the first four days of storage.
Table 24: Changes in TVC of burger samples during storage (X103)*
Muscle
cut
Mushroom
(%)
Storage time (days)
0 2 4 6 8 Mean
Ribeye 0 1.80±0.01 13.70± .00 135.80± .00 1105.00±.71 10600 ± 141.42 2172.20c
20 1.11±0.01 6.30± .00 129.00±1.41 1350.00±14.14 13900± 98.42 3077.28g
40 1.37±0.01 1.69± .01 116.00±1.01 1125.00±0.01 10100± 102.00 2268.81d
60 1.49±0.01 1.39± .01 69.00± 1.41 670.00±0.01 8200 ± 82.82 1788.38b
Round 0 0.98±0.00 6.45± .07 59.50± .71 890± 14.14 8900± 60.12 2151.39c
20 2.41±0.01 30.00±.00 173.00±1.41 2390± 14.14 15900± 141.41 3699.08h
40 2.21±.01 12.50±.14 122.00±2.83 1470 ± 14.14 12100± 161.42 2741.34e
60 1.89±.01 20.10±.14 139.00±1.41 1700± 12.01 13500± 147.42 3072.20g
Chuck 0 0.85±.01 4.80± .14 50.00± 0.00 590± 10.14 7500± 67.42 1629.13a
20 1.80±.00 15.10± .14 136.00±2.41 1600 ± .00 12800± 89.42 2910.58f
40 1.90±.00 19.20± .14 99.50± .71 1190 ± 14.14 12400± 141.42 2742.12e
60 1.75±.01 13.00± .00 113.00±1.40 1300 ± .00 13200± 141.42 2925.55f
Mean 1.63a
12.02a
111.75b
1198.79c
11666.67d
*Values are in means (cfug-1) ± SD and means with the same superscript in the same column are not
significantly different (P > 0.05).
The total viable counts of organisms were found to increase progressively
with storage time. No general trend was observed on table 23 to indicate the
effect of mushroom inclusion on the total viable counts of hamburgers during
storage. None the less, on the last day of storage muscle of round burger
samples with 20% and 60% mushroom had the highest TVC of 15,900±141.42
and 13,500±141.42 respectively. Chuck sample without mushroom and ribeye
97
sample with 60% mushroom had the lowest counts of 7,500±141.42 and
8,200±282.84 respectively. Hamburger is a fast food normally cooked for a
short period of time (10-12 minutes) according to Green (2008). It might appear
that the cooking time was not enough to achieve complete destruction of
contaminating microorganisms. The contamination might have arisen from the
sources of raw materials (meat and mushroom). More so, no antibiotic was used
in the recipe for the purpose of inhibiting microbial growth. As a fast food
according to Foskett et al (2004), it might have been thought unnecessary to use
any preservative. However, the burger samples did not show physical spoilage
characteristics at the end of the storage period.
4.6.6 Contribution of mushroom to the coliform count of hamburger
Table 24 shows that there was scanty initial coliform count. The coliform
count increased gradually during storage, though the counts of coliform
organisms were low on the last day of storage. The coliform counts for chuck
burger sample without mushroom and muscle of round sample with 20%
mushroom were higher throughout the period of storage ranging from 0.80 ±
0.00 x 102
CFUg-1
to 201.00 x 102 CFUg
-1 and 0.50 x 10
2 CFUg
-1 to 105 2.41 x
102 CFUg
-1 respectively. Table 24 also shows that ribeye and muscle of round
samples with 40% and 60% mushroom respectively had lower counts of
coliform up to the sixth day of storage. However, muscle of round burger
sample without mushroom was found to have the lowest coliform counts
(24.00±0.00 x 102 CFUg
-1) on the last day of storage.
98
Table 25: Changes in coliform counts of burger samples during storage (X102)*
Muscle
cut
(%)
Mushroom
Storage time (days)
0 2 4 6 8 Mean
Ribeye 0 .05± .07 1.50± .14 4.60± .14 11.60±.21 77.00± 1.41 18.59a
20 .00± .00 1.85± .07 6.10± .24 15.4± .05 85.00±1.81 26.70b
40 .02± .00 1.90± .18 6.50± .10 16.30± .14 99.00± 1.5 24.78c
60 .00± .00 .70± .00 2.60± .10 6.80± .15 52.00± .00 12.42d
Round 0 .00± .00 1.20± .00 3.90± .12 10.1± .14 24.00± .00 7.84e
20 .50± .00 3.00±.94 9.10± .20 22.6± .14 105.00±2.41 28.04f
40 .05± .07 .50±.00 2.20±.74 5.90 ± .12 49.00± 1.21 11.53g
60 .00± .00 1.10±.44 3.15± .21 8.10± .05 56.00± 0.00 13.67h
Chuck 0 .80± .00 5.10± .24 15.20± .14 29.10± .14 201.00±1.41 50.24c
20 .40± .00 2.00±.0.00 6.90± .17 17.400 ± .32 95.50±0.71 24.44c
40 .10± .00 1.60± .00 5.00± .12 12.60 ± .14 80.00±0.00 19.86j
60 .10± .00 1.35± .07 4.10±1.20 11.10 ± .27 71.50± 2.12 17.63k
Mean 0.18a
1.82b
5.78c
13.92d
82 .92e
*Values are in mean (cfug-1
) ± SD and means with the same superscript in the same column are not
significantly different (P >0.05).
The coliform count on table 24 did no follow any specific pattern to suggest the
effect of mushroom addition on the microbial activities of the hamburger
samples.
4.6.7 Changes in mould counts during storage
The mould growth during the first two days of storage was scanty as
shown on table 25. This could be due to the observed initial high water activity
of 0.84-0.96(Table 15) which might not have favoured mould proliferation.
Most mould growth was observed from the fourth day analysis.
99
Table 26: Mould counts of burger samples with and without mushroom(x10)2 *
Steak
cut
(%)
Mushroom
Storage time (days)
0 2 4 6 8 Mean
Ribeye 0 0.0 0.0 0.0 0.0 0.1 ± 0.0 0.02a
20 0.0 0.0 0.1 ± 0.0 0.30 ± 0.0 1.0 ± 0.0 0.28b
40 0.0 0.1 ±0.0 0.25 ± 0.7 0.90 ± 0.17 2.40 ± 0.0 0.73f
60 0.0 0.55 ± .07 1.6 ± 0.14 3.10 ± 0.09 9.90 ± 0.00 3.03h
Round 0 0.0 0.0 0.0 0.1 ± 0.0 0.20 ± 0.0 0.06a
20 0.0 0.1 ± 0.0 0.2 ± 0.0 0.60 ± 0.0 1.40 ± 0.0 0.46d
40 0.0 0.0 0.0 0.0 0.10 ± 0.0 0.02a
60 0.0 0.0 0.1± 0.0 0.25 ± 0.07 1.0 ± 0.14 0.27b
Chuck 0 0.0 0.0 0.30 ±0.0 0.80 ± 0.0 3.90 ± 0.18 1.00g
20 0.0 0.0 0.15± 0.05 0.40 ± 0.05 1.20 ± 0.15 0.35c
40 0.0 0.0 0.10 ± 0.0 0.35 ± 0.09 2.10 ± 0.07 0.51d
60 0.0 0.0 0.20 ± 0.0 0.80 ± 0.0 2.25 ± 0.09 0.65e
Mean 0.0a
0.06b
0.25c
0.63d
2.13e
*Values are in means (CFUg-1) ± SD and means with the same superscripts in the same column are
not significantly different (P > 0.05).
The mould count was generally low. Ribeye burger sample with 60%
mushroom had the highest (9.90 ± 0.0 x102 CFUg
-1) followed by chuck burger
sample without mushroom (3.90 ± 0.18 x 10-2
CFUg-1
). The lowest (0.10 ± 0.0 x
10-2
CFUg-1
) was found with ribeye sample without mushroom and muscle of
round sample with 40% mushroom, both of which did not show any growth up
to the sixth day of storage. It was still observed that no regular pattern could be
established to suggest the effect of mushroom inclusion on the mould count of
the hamburger samples.
100
CHAPTER FIVE
5.0 CONCLUSION AND RECOMMENDATIONS
5.1 CONCLUSION
The reduction in the quantity of nutrients of hamburgers due to addition
of mushroom observed in this study does not make the hamburgers with
mushroom nutritionally inadequate, since the hamburgers with mushroom were
found to still make good contribution to the daily value of most of the nutrients.
In view of the outstanding problems of red meat consumption, vis-a-vi-s the
numerous health benefits of mushroom, it is considered safer to partially replace
hamburger with mushroom for optimum health.
5.2 RECOMMENDATION
From the fore-going of this study, the following recommendations are
drawn:
i. Should hamburger be produced with the intention of storage, it is
necessary to use a suitable chemical preservative, such as benzoic acid
or its benzoate salt to inhibit microbial activities and ensure optimum
shelf stability.
ii. Hamburger should be refrigerated, if not sold/consumed on the day of
production to disallow microbial activities, or else should be discarded
after two days of production since it is not shelf stable under ambient
condtions.
iii. Research should be conducted for appropriate cultivation of
mushroom for subsequent use, and to meet public demand.
101
REFERENCES
Allan, R. (2010). Nutrition Facts on Oyster Mushroom
@http://www.livestrong.com/article/294007-nutrition-facts-on-oyster-
mushroom/ Retr. 03 -12 -2010.
American Dietetics Association (2010) @http://www.eatright.org/public/
content.aspe?id=64424.58955. Retr. 03 -12 -2010.
Anderson, E.E and Fellers, C.R (1942). Food Value of Mushrooms (Agaricus
compectris). Proc. Am. Soc. Hort. Sci, 41, 301-304.
Andrews, N.C. (1999) Disorder of Iron Metabolism. N. Engl. J. Med. Abs. 341:
1986-95 –pubmed.
AOAC (1995). Official Methods of Analysis 16th ed, Assoc of Official Anal.
Chem Gaithersburg, Maryland, USA. Pp 1-64.
Arpita (2009) Health Benefits of Mushroom @http://www.Dynsveda.com/
tipson/health-benefits-of-mushroom/ Retr. 03 -12 -2010.
Bahl, N. (2000). Handbook of Mushrooms 4th ed., Vijay Prinlani for Oxford
and IBH Pub. Co. Pvt. Ltd., Japath, New Delhi.
Bano, Z., Srinivasan, K.S., and Strivastava, H.C. (1963). Amino acid
composition of the protein from a mushroom (Pleurotus sp). Appl.
Microbiol., 11, 184-187.
Bano., Z. (1976). The Nutritive Value of Mushrooms. Indian Mushroom Sci., 1,
473-487.
Banwart, G. J. (1998) Basic Food Microbiology 2nd
ed., CBS pub. And Distr.
PVT. Ltd. New Delhi.
Barley, A.J (1984). Recent Advance in the Chem. Of Meat, The Royal Society
of Chem. London, 47, 22-40.
Barlow, J. ed (2010). Chemical Analysis of Mushrooms show their Nutritional
Benefit. Live Sci. @ http://news.illinois.edu/news/05/
0214mushrooms.html. Retr. 03 -12 -2010.
102
Barros, L., Baptista, P., Correia, D. M., Casal, S., Oliveira, B. and Ferreira, I. C.
F. R. (2007). Fatty Acid and Sugar Composition and Nutritional Value of
Five Wild Edible Mushrooms from North East Portugal. Fd. Chem. vol.
105, Issue 1, p. 140.
Bastin, S. (2007). Nutritional Value of Meat. Co-operative Extension Services,
FS – SSB 113, Kenturkey, UK.
Beetze, A. and Kustudia, M. (2004). Mushroom Cultivation and Marketing.
Hort.prod. Guide, ATTRA Publication, 1, 87.
Block, R.J and Mitchell, H.H (1946). The Correlation of the Amino Acid
Composition of Proteins with their Nutritive Values. Nutri. Rev. 16, 249-
278.
Bosselmann, A., Moller, C., Stenihait, H., Kirchgessner, M. and Schwarz, F.J.
(1995). Pyridinoline cross-link in Bovine Muscle Collagen. J. Fd. Sci. 60
(5), 953-958.
Cattlemen’s Beef Board and National Cattlemens Beef Association (2006) @
http://www.beeffoodservices.com/CMDOCS/BFS/BeefU/BeefU
/factsheets/12/nutrition.pdf. Retr. 03 -12 -2010.
Chang S.T and Miles, P. G. (1989). Edible Mushrooms and their Cultivation.
CRS press Inc. Florida Pp 27-38.
Chang, S and Miles, P.G (2004). Mushrooms, Cultivation, Nutritional Value,
Medicinal Effect, and Environmental Impact, Ist ed., CR C Press.
Chang, S. and Tu, C.C (1978). Auricularia Sp.; In, The Biology and Cultivation
of Edible Mushrooms, Chang. S.J and Hayes, W.A eds., Academic Press
New York, Pp 605-625.
Chang, S. T. and Buswell, J. A. (1996). Mushroom Nutriceuticals. World J.
Microb. Biotechnol. 12: 473-476.
Chang, S.T. and Mshivgeni, K. E. (2001). Mushrooms and their Human Health:
their growing significant. The University of Nambia, Windhock 1-79.
Chen., S. Oh, S., Plung, S., Hur, G. Ye, J.J., Kwok, S.L., Shrode, G.E., Belury,
M., Adam, L.S. and Williams, D.L (2006). Anti-Aromatase activity of
Phytochemicals in white bottom Mushrooms. (Agricus bisporus). Cancer
Res. 66 (24), 120, 126-134.
103
Chong, K.S., Chye, F.Y., Lee, J.S and Markus A. (2007). Nutritional properties
of some edible wild Mushrooms in Sabah. J. appl. Sci. 7 (15), 2216-2221.
Crisan, E.V. and Sands, A. (1978). Nutritional value. In Chang, S.T. and Hayes,
W. A. (eds). The Biology and Cultivation of Edible Mushrooms.
Academic Press Inc. London. P 137-165.
Crouse, J.D., Koomararae, M., Seideman, S.D (1991). The relationship of
muscle fiber size to tenderness of beef. Meat Sci., 30 (4), 295-302.
Dalman, P. R. (1986). Biochemical Basis for the Manifestation of Iron
Deficiency. Ann. Rev. Nutri. Abs. 6-13-40 pubmed.
Dickman, M.E (1987) Fat reduction in animals and the effects on palatability
and consumer acceptance of meat products. Proc. Recip. Meat Conf. 40,
93.
Diet anf fitness today (2010 a) Recommended dietary Allowance @
http://www.dietandfitnesstoday.com/recommended-dietary-
allowance.php. Retr. 32 -11 -2010.
Diet and Fitness today (2010 b) Nutrition facts and calories in Mushrooms,
shiitake, cooked, without salt @ http://www.dietandfitnesstoday.
com/calories-nutrition-facts.php?id=11798. Retr. 23 -11 -2010.
Diez, V.A. and Alvarez, A. (2001). Compositional and Nutritional Studies on
two Wild Edible Mushrooms from Northwest Spain Fd. Chem. vol. 75.
Issue 4. P 417-422.
Doug, O. (2008). Organic mushroom growing kits – certified organic
mushroom logs. On line at, http://www.gmushrooms.com/pots. Retr. 04 -
12 -2010.
Dubost, N.J (2006). Identification and Qualification of Egrothionine in
cultivated mushrooms by Liquid Chromatography-mass spectroscopy.
Int. J. of Medicinal Mushrooms, 8, 215-222.
Eating Well (2010) @ http://www.eatingwell.com/recipes/healthy-gmuscle of
round-beefrecipes. Rety. 03 -12 -2010.
Edwards, R.L (1975). Ninth Int. mushroom science congress. Mushroom J. 4,
223-227.
104
Esselen, W.B. and Fellers, C.R. (1946). Mushrooms for food and flavour. Mass
Agr. Exptl. Sta. Bull. 434.
Farlex (2009) The Free Library. Mushrooms do replace Meat @
www.quested.com/online-library. Retr. 03 -12 -2010.
Faustman, C. (1994). Post mortem changes in muscle foods, In; Muscle Foods,
Kinsman, D.M., Kotwa, A.W and Breidenstein B.C. (eds). Chapman and
Hall Inc., New York.
FAO (Food and Agricultural Organisation) (1972). Food Consumption Table
for use in East Asia. Food Policy Food and Nutri. Div. Food and Agric.
Org. U. N., Rome.
FAO/WHO (Food and Agricultural Organisation/World Health Organisation)
(1991). Protein Quality Evaluation. Report of a Join FAO/WHO Expert
Consultation. Food and Nutrition Paper 51. FAO Rome.
Food Safety and Inspection (2002). Focus on muscle of round beef. Fact sheet
(1). @
Forrest, J.C., Aberle, E.D., Herdrick, B.B., Judge, M.D., and merkel, R.A.
(1995). Principles of Meat Science. W.H Freeman and Co., San
Frabcisco.
Foskett, O., Ceserani, V. and Kinton R. (2004). Practical Cookery, 10th ed.,
Hodder and Arnold Pub., London, Pp. 60-61.
Foulds, J. (2010). Nutrition Facts for Mushroom after Cooking @
http://www.livestrong.com/article/262719-nutrition-facts-for-
mushroomsaftercooking. Retr. 04 -12 -2010.
Fox, B.A., and Cameron, A.G (1977). Food Science-A Chemical Approach, 1st
ed., Hodder and Stoughton, London.
Franklin, B. (2003). Meat and dairy products, In; Prescription for Dietary
Wellness, 2nd ed., Balch, P.A. (ed.), Penguim Group Inc., New York. Pp.
222-224.
Genccelep, H., Uzun, U. Tuncturk, Y. and Demirel, K. (2009). Determination of
Mineral Contents of Wild Grown Edible Mushrooms. Fd. Chem. vol.
113. Issue 4, P.1033.
105
Gracey, J.F and Collins, D.S (1992). Anatomy, meat composition and quality,
In; Meat Hygiene, 9th ed., Bailliere Tindall, London. Pp 67-78.
Graiones, N. (2001). Eating Food-Foods that Heal, 1st ed., Anness Pub. Ltd.,
London. Pp. 62.
Gray, W.D. (1970). The Use of Fungi as Food and in Food Processing, 1st ed.,
Butterworth and Co., London.
Green, D. (2008). Saturday kitchen. @
http://www.bbc.co.uk/foods/recipes/database/spicybeef burger - 71337.
Retr.20 -10 -2010.
Grube, B.J., Kao, Y., Eng, E.T., Kuon, A., and Chen, S. (2007). White bottom
mushroom phytochemicals inhibit aromatase activity and breast cancer
cell proliferation. Division of Immunology, Beckman Res. Inst. of the
City of Hope, Duarte, CA 91010.
Guillamon, E., Garcia-Lafuente, A., Lozano, M., Darrigo M. A. Vilaries, A. and
Alfredo. J. (2010). Edible Mushrooms: Role in the Prevention of
Cardiovascular Diseases. Fitotera pia. Vol. 81. Issue 7. P 715.
Hagiwara, S., Takahashi, M., Shen, Y., Kaihou, S. Tomiyama, T., Yazawa, M.,
Janai. Y., Siri, T., kazusaka, A., Tarazawa, M. (2005). Phytochemicals in
the edible tanogi-take mushroom (Pleurotus cornueopiae). Biosci.,
Biotechnol. Biochem. 69 (8), 1603-1605.
Hallock, R.M (2008). The taste of mushrooms. @
http://www.mushroomexpert.com/hallock-01.html. Retr.15 -10 -2010.
Harrigan, W.F and McCance, E.M (1976). Laboratory methods in; Food and
Dairy Microbio. Academic Press, London.
Hayes, W. A., and Haddad, N. (1976). The Food value of the cultivated
mushrooms and its importance to the mushroom industry. The Mushroom
J. 40, 104-110.
Heleno, S.A., Barros, L., Sousa, M. J. Martins, A., and Ferreira, I. C.F.R.
(2009). Study and Characterization of Selected Nutrients in Wild
Mushrooms from Portugal by Gas Chromatography. Microchemical J.
Vol. 93, Issue 2. P 195.
106
Honikel K.O. (1998). Reference methods for the assessment of physical
characteristics of meat. Meat sci., 49:4, pp 442-457.
Hughes, D.H. (1962). Preliminary Classification of Lipid constituents of the
cultivated mushroom (Agaricus compestris). Mushroom Sci, 1. 540-546.
Ikeme, A.I (1990). Meat Science and Technology: A Comprehensive
Approach,1st ed., Africana Feb. Pub. Ltd. Onitsha.
Insel P. Turner, R. E. and Ross, D. (2006). Discovering Nutrition. 2nd
ed., Jones
and Bartlett pub. Int. Barb House, Barb Mews, London w6 7PA UK.
Karen, C.R.D. (2007). How risky is red meat? Nutrition Notes, American Inst.
For Cancer Res. Washington.
Kavishree, S., Hemarathy, J. Lokesh, B.R., Shashirekha, M.N. and
Rajarathnam, S. (2008). Fats and Fatty Acids of Wild Edible Mushrooms.
Fd. Chem. vol. 106. Issue 2. P. 597.
Kinsman, D.M (1994). Historical Perspectives and Current trend, In; Muscle
Foods, Kinsman, D.M and Kotwa, A.W and Breidenstein, B.C. (eds),
Chapman and Hall Inc., New York.
Lan, Y.H., Novakovski, J.R.H., Mccusker, M.S., Bewer, T.R. and Mckeith, F.K.
(1995). Thermal gelation of Pork, beef, Fish, Chicken and Turkey
muscles as affected by heating rate of pH. J. Fd. Sci., 60 (5), 936-945.
Lawrie, R.A. (1991). Meat Science, 5th ed., Pengamon Press, Oxford.
Lee, G.F., and Stumm, W. (1960). Determination of Ferrous iron in the
presence of ferric iron using bathopenanthroline. J.Ame. Water Works
Ass., 52, 1567.
Lendon-Smith, M.D (1985). Lendon-smith Low Stress Diet, McGraw-Hill Book
Co., New York, Pp. 45-65.
Leon-Guzman, M.F., Silva, I, and Lopez, M.C. (2007). Proximate Chemical
composition, free amino acid contents, and free fatty acid contents of
some wild mushrooms from queretaro, Mexico. J. of Agric. Food Chem.
45 (11), 4329-4332.
Lintzel, W. (1941). The nutritional value of edible mushroom protein. Biochem.
Acta. 308, 413-419.
107
Malony, A. (1999), The quality of meat, R and H Hall Tech. Bull. 4.
Masakazu, H., Yoshifumi, M., and Yasushi, S. (2003). Forestry and Forest
Products Research. Inst. of Japan.
Mayo Clinic (2010) @http://www.mayoclinic.com/health/healthy-
recipes/NU00397. Retr.15 -10 -2009.
McConnell,J.E.W. and Essellen, W.B.Jr.(1947). Carbohydrates in Cultivated
Mushroom (Agaricus campestris). Food Research. 12:118.
Medline Plus Medical Encyclopedia (2010). Vitamin A @
http://www.nlm.nih.gov/medlineplus/ency/article/002400.htm. Retr. 20 -
01 -2011.
Mendil, D., Uluozlu, O.O., Hasdenir, E. and Glar, A. (2004). Determination of
Trace Elements on some Wild Edible Mushroom Samples from
Kastamonu, Turkey. Fd. Chem. Vol. 88. Issue 2, P. 281.
Moore, M. (2003). Immortal mushrooms, In; Prescription for Dietary Wellness,
2nd
ed., Balch, R. (ed), Penguin Group Inc., New York. Pp. 167-168.
Mshandete, A.M. and Cuff, J. (2007). Proximate and nutrient composition of
three types of indigenous edible wild mushrooms grown in Tanzania and
their utilization prospects, Afric. J. of Fd., Agric. Nut. and Development.
7: 6.
MSNBC (2006) Bringing Mushroom out of the Dark. @
http://www.shroomery.org/forums/showflat.php/Cat/D/Number/8045435
Retr. 20 -10 -2009.
Mukherjee, A. (2010). Health Benefits of Mushroom @
http://www.organicfacts.net/health-benefits/vegetables/health-benefits-of-
mushroom.html. Retr. 03 -12 -2010.
New American Dream (2010). Food/Beef: Health and Beef Consumption @
http://www.newdream.org/food/beef-health/php. Retr. 02 -12 -2010.
NIIR Board (2006). Chemical composition, Anti-nutritional Factors and Shelf-
life of Oyster Mushroom (Pleurotus ostreatus). Handbook on Mushroom
Cultivation and Processing (with Dehydration, Preservation and
Canning). Pub. Asia Pacific Business Press. Inc.
108
Nutrition Factsheets (2010a) Foods details @ caloriecount.about.com/calories-
hamburger-large-single-meat-patty-i21112. Retr. 24 -11 -2010.
Nutrition Factsheets (2010 b) Iron @ http://www.ohionline.osu.edu/hyg-
fact/5000/559.html. Retr. 24 -11 -2010.
Nurul, H., Noryati, I., Alistair, T. and Lik, J. (2009). Physico-chemical
Properties of Malaysian Commercial Beef Frankfurters. @
http://libra.msra./cn/Publication/14310616/ physico-chemica- properties-
of Malaysian- commercial-beef-frankfurter & text= PHYSICO-
CHEMICAL PROPERTIES OF MALAYSIAN BEEF
FRANKRURTERS.
Obanu, Z.A (1978). Protein Solubility in SDS – β-mercapto ethanol as a simple
Efficient Index of Protein Quality of IM Meat. West African J.Biol and
Appl. Sci. 21, 71-74.
Onwuka, G.I (2005) Food Analysis and Instrumentation, 1st ed., Naphtali
Prints, Lagos, Pp 29-73.
Organic Mushroom Growing Kits (2010). Mushroom Logs @
http://www.mushrooms.com/POTS.HTM. Retr.19 -11 -2010.
Park K. (2001). Nutritional value of a variety of Mushrooms. @
http://www.ucc-iwmi.org/symposium. Retr. 15 -10 -2009.
Pearson, A.M and Gillett, T.A (1996). Processed Meat, 3rd ed., Chapman and
Hall, New York. Pp 31, 41, 51.
Pearson, D. (1976). The Chemical Analysis of Foods, 7th ed., Church Hill
Living stone, Edinburgh London.
Potter, N. N. and Hotchkiss, J. H. (1995). Food Science, 5th
edition, CBS
Publishers & Distribution, Daryaganyi, New Delhi pp 240-243.
Ribeiro, B, Guides de Pinho, P. Andrade, B. P., Baptista, P. and Valentao P.
(2009). Fatty Acid Composition of Wild Edible Mushroom Species: A
comparative study. Microchemical J., vol. 93, Issue 1, P. 29.
Rose, W.C (1937). The nutritive significance of the amino acid and certain
related compounds. Science, 86, 289-300.
109
Rowe, R.D.W (1983). Centre for Studies in Int. Relations and Development.
Fd. Res. Quarterly, 4: 3.
Shakelfood, S.D., Koomararie, S.D., Miller, M.F., Crouse, J.D., and Reagan,
J.O (1991). An evaluation of tenderness of the Longissimus muscle on
angus by Hereford versus Brahman crossbreed heifers. J. of Anim. Sci.
69, 171.
Solomko, E. F., Panchento, L.P. and Silchankova, R. K. (1984). Lipid Content
and Fatty Acid Composition of the Higher Edible Fungus – the Oyster
Mushroom Pleurotus ostreatus (Fr.) Kummer.Prikl Briokhim. Mikrobiol.
Southerland, D. and Rhodes, S. (1992). Cookery for the Catering Industry,
North Cote House, UK. Pp, 332.
Stem, R. (2009). Daily Red Meat raises Chances of Dying Early @
http://www.washingtonpost.com/wp-dyn/content/article2009/03/23/
AR200903231626html:pid =topnews. Retr.24 -11 -2010.
Uncyclopedia (2008). Burgers @
http://uncyclopedia.wikia.com/wiki/Burgers#Burgers Retr.20 -10 -2009.
USDA (2005) US Food and Drug Admin, Agric. Res. Service (2005),
Compounds may help produce juicer meat, Science Daily, Nov. 1.
USDA (2006) US Dept. of Agric. Res. Service. USDA National Nutrient Data
Base for Ref. @ http://www.ars.usda. gov/ba/bhnrc/ndl. Retr. 23 -10 -
2009.
USDA (2010). Nutritional Information on USDA Commodity, Beef, Patties
(100%), frozen, cooked. @ http://www.elook.org/nutrition
/beef/6185.html. Retr. 24 -03 -2010.
USDA Research Service (2005) Beef Nutritional Facts @
http://www.beef.fadservice.com/
CMDoes/BFS/beefu/BeefUfactsheets/12/nutrition.pdf. Retr. 03 -12 -
2010.
Varnam, A.H and Sutherland J.P. (1995). Meat and Meat Products: Tech. Chem
and Microbio, 3rd, ed., Fd. Pds. Series, Chapman and hall, London.
Vernon, A.R. (1988). Meats, In; Foods, EMC Pub. Co., Minnesota.
110
Wasser, S.P (2002). Review of medicinal mushrooms advances: Good news
from old Allies. J. Am. Bot. Council, 56, 28-33.
Wikipedia (2008). @ http://en.wikipedia.org/wikipedia.org/wiki/Gmuscle of
round beef. Retr. 23 -11 -2010.
Wikipedia (2010) Beef fats @ http:www.en.wikipedia.org/wiki/dietary-
minerals. Retr. 23 -11 -2010.
Wooster (1954). Study of Edible Mushroom Grown on Eucalyptus
camaldulensis. @ http://pjbs.org/pjnonline/fiin 137.pdf.
Yashajahu, P. and Clifton, E.M (1996) Food Analysis: Theory and Practice, 3rd.
ed., SK. Pub. Darya Ganji, New Delhi. Pp. 460.
Yashima, B (2008). @ http://media.www.theticker.org/media/storage/paper
909/news/2008/09/22/Lifestyles.
Yilmez, N., Solmaz, M., Turkekul, I. and Elmastas (2006). Fatty Acid
Composition of some wild Edible Mushrooms growing in Middle Black
Sea Region of Turkey. Fd. Chem. vol. 99, Issue 1, p 168.
111
APPENDIX 1
DEPARTMENT OF FOOD SCIENCE AND TECHNOLOGY
UNIVERSITY OF NIGERIA, NSUKKA
TRAINED PANEL ASSESSMENT FORM
Thesis Title: Contribution of Mushroom to the Physicochemical, Nutritive
and Sensory Properties of Hamburger.
Sir,
Presented before you are samples of burgers produced to test the
contribution of mushroom to the sensory properties of hamburger. Please assess
them carefully and objectively following the scale of ranking below for degree
of “like and dislike”
Like extremely 9
Like highly 8
Like moderately 7
Like slightly 6
Neither like nor dislike 5
Dislike slightly 4
Dislike moderately 3
Dislike highly 2
Dislike extremely 1
Samples/sensory
properties
A1 A2 A3 A4 B1 B2 B3 B4 C1 C2 C3 C4 Total
Texture/mouth feel
Colour
Odour Aroma
Taste
General acceptability
Total
Name of Assessor Signature/Date
Thanks
Olonta, Oobe Agaba
112
APPENDIX 2
ANALYSIS OF VARIANCE (ANOVA) TABLES
Protein
Sources of
error
DF SS MS Fcal Ftab
5% 1%
Significance
Treatment 11 140.264 12.751 135.190 2.7200 4.2257 **
Error 12 2.264 0.094
Total 23 142.528
Fat
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 60.663 5.515 1019.693 2.7200 4.2257 **
Error 12 0.130 0.005
Total 23 60.793
Ash
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 3.709 0.337 82.400 2.7200 4.2257 **
Error 12 0.098 0.004
Total 23 3.807
Moisture
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 204.336 18.576 188.670 2.7200 4.2257 **
Error 12 2.363 0.098
Total 23 206.699
Magnesium
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 829.465 75.406 860.642 2.7200 4.2257 **
Error 12 1.051 0.088
Total 23 830.516
Iron
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 2.904 0.264 123.104 2.7200 4.2257 **
Error 12 0.026 0.002
Total 23 2.929
113
Phosphorus
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 4248.305 360.210 257.874 2.7200 4.2257 **
Error 12 17.972 1.498
Total 23 4266.277
Zinc
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 44.835 4.076 91336.726 2.7200 4.2257 **
Error 12 0.001 0.000
Total 23 44.835
Calcium
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 0.000 0.000 36.886 2.7200 4.2257 **
Error 12 0.000 0.000
Total 23 0.000
Sodium
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 0.009 0.001 133.444 2.7200 4.2257 **
Error 12 0.000 0.000
Total 23 0.009
Potassium
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 0.060 0.005 1.096 2.7200 4.2257 ns
Error 12 0.060 0.005
Total 23 0.121
Vitamin C
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 0.341 0.031 15.004 2.7200 4.2257 **
Error 12 0.025 0.002
Total 23 0.365
Vitamin A
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 138.623 12.062 48908.590 2.7200 4.2257 **
Error 12 0.003 0.000
Total 23 138.626
114
Thiamin
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 0.006 0.001 32.122 2.7200 4.2257 **
Error 12 0.000 0.000
Total 23 0.006
Niacin
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 0.481 0.044 1.018 2.7200 4.2257 ns
Error 12 0.515 0.043
Total 23 0.996
Colour
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 88.967 8.088 3.952 1.8721 2.4042 **
Error 108 221.000 2.046
Total 119 309.967
Texture
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 142.767 12.979 4.847 1.8721 2.4042 **
Error 108 289.200 2.678
Total 119 431.967
Aroma
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 114.892 10.445 7.774 1.8721 2.4042 **
Error 108 145.100 1.344
Total 119 259.992
Taste
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 116.167 10.561 2.622 1.8721 2.4042 **
Error 108 435.000 4.028
Total 119 551.167
General
acceptability
Sources of
error
DF
SS
MS
Fcal
Ftab
5% 1%
Significance
Treatment 11 179.892 16.354 5.789 1.8721 2.4042 **
Error 108 305.100 2.825
Total 119 484.992
115
UNIVERSITY OF NIGERIA, NSUKKA SCHOOL OF POSTGRADUATE STUDIES
APPLICATION FOR APPROVAL OF TITLE OF DISSERTATION
NAME OF STUDENT OLONTA, Oobe Agaba
REGISTRATION NUMBER PG/M.Sc/07/43516
DEPARTMENT Food Science and Technology
FACULTY Agriculture
DEGREE IN VIEW M. Sc
EXPECTED YEAR OF GRADUATION 2011
PROPOSED TITLE OF DISSERTATION Contribution of Oyster
Mushroom
(Pleurotus sarjor-caju) to the Physyco-
Chemical, Nutritive and Sensory
Properties of Hamburger
SYNOPSIS
INTRODUCTION
Meat is defined as the flesh of animals which is suitable for use as food. Although
meat eating remains at a high level, there have been distinct changes in the type of meat
eaten. The most striking is the rise in consumption of poultry and sea food and less red meat.
The success of fast-food outlets means that increasing quantities of beef and, to a lesser
extent, other meats are eaten as burgers and similar products. Mushroom is the fleshy, spore
bearing fruiting body of a fungus, typically produced above ground on soil or on its food
source. Mushroom is more of common application to macroscopic fungi fruiting bodies than
one having precise taxonomic meaning. The majority of mushrooms belong to
Hymenomycetes (Basidiomycotina) while others belong to Discomycetes (Ascomycotina).
How long has been eating mushroom is, of course, impossible to determine, but one can
speculate with reasonable assurance that such fungi have periodically been a part of his diet
for many centuries. Until recent times in the United States, mushrooms were used primarily
as a condiment to garnish steaks. With the development and expansion of the mushroom
canning industry however, they appear to be gaining favour as a base for soup and as
ingredient in many dishes in which they were formerly seldom used. Mushrooms represent
one of the world’s greatest untapped resources of nutritious and palatable foods. Some
mushrooms are edible while others are poisonous. Edible mushrooms are distinctive in some
ways. Once their distinguishing features are learned, they cannot be confused with any
116
poisonous species. Mushroom is being cultivated in many parts of the world presently.
Commercial mushroom growing was first initiated in India. Mushrooms have the capacity to
convert nutritionally valueless substances into high protein food. Ground beef, beef mince or
hamburger meat (in North America) or mince(d) meat (in the rest of the English world) is a
ground meat product made of beef finely chopped by a meat grinder. Burgers are usually
made from ground meat or meat substitute, then reshaped to form patties and cooked and
eaten. Burgers made with beef are traditionally known as hamburgers, though due to the
profusion of burger types over the last few decades are also called beef burgers. Burgers not
made from beef are often marketed as more exotic than hamburger or as being healthier than
beef patties. In the UK, the world burger often refers to the filling of a burger sandwich (that
is what in USA would be termed a patty).
METHODOLOGY
Fresh beef cuts (ribeye, chuck muscle and muscle of round) and mushroom (Pleurotus sajor -
caju) were procured from Ugbokolo market. The mushrooms were trimmed. Both beef cuts
and mushrooms were washed and ground separately. Four burger samples were prepared
from each beef cuts with different combinations (0%, 20%, 40%, 60%) of mushroom. The
burger samples were analysed for proximate, mineral element (magnesium, iron, phosphorus,
zinc, calcium, sodium and potassium), vitamin (vitamin C, A, thiamin, riboflavin and niacin)
content. Protein solubility and sensory analysis were also conducted on the burger samples.
The burger samples were subjected to water activity, pH and microbial analysis during eight
(8) days storage under ambient conditions. The data generated were analysed using ANOVA.
The means were separated using the studentised Duncan multiple range test.
RESULTS
The inclusion of mushroom caused a general decrease in the protein, fat, ash, mineral
element, vitamin as well as the soluble protein contents and an increase in the carbohydrate
content. Burger samples without mushroom differed significantly (P < 0.05) from samples
with mushroom in protein, ash, fat, soluble protein, mineral element (magnesium, iron,
phosphorus, zinc, calcium and sodium) and vitamin (vitamin C, A, thiamin and riboflavin)
contents. Not withstanding this decrease, the burgers with mushroom wee found to still make
appreciable contribution to the Daily Value (DV) of most of the nutrients in one serving size
of 100g. The changes in the potassium and niacin contents of all the burger samples did not
show significant differences (P > 0.05). The pH and water activity of the burger samples
117
ranged between 5.40-5.65, being slightly acidic and 0.84 – 0.96 respectively. The degree of
“likeness” of the sensory qualities and general acceptability was rated highest for burgers
without mushroom. The inclusion of mushroom resulted in decreased rating of likeness for
burger samples with mushroom. The least rating (slightly dislike) was observed in the taste of
ribeye muscle, and muscle of round burger samples with more than 20% mushroom. Burgers
made from chuck muscle were most preferred to burgers from other muscle cuts. The
microbial counts (TVC, mould and coliform count) for burgers at the end of 8 days storage
under ambient conditions showed that significant differences (P < 0.05) existed among
muscle at the various levels of mushroom. No specific trend could be established to account
for the addition of mushroom on the microbial activities of hamburger during storage.
Coliform and mould counts were generally lower than TVC throughout the storage period.
No physical sign of spoilage was observed at the end of 8 days of storage.
………………… …………. ………………………..
…………….
Olonta, Oobe Agaba Date Prof. Okonkwo, T. M
Date
(Student) (Supervisor)
…………………… …………. ………………………..
…..………..
Dr. (Mrs) Ani, J. C. Date Dr. Agbo, C. U. Date
(Head of Department) (Faculty Rep. SPGS)