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Page 1: International Journal Applied Sciences & · PDF fileProximate analysis, ... cultivars like the bitter cassava. ... communis), melon seeds (Citrullus vulgaris) and fluted pumpkin seeds

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International Journal of Applied Sciences & Engineering

www.ijapscengr.com; [email protected]

RESEARCH ARTICLE

Cassava Seeds as Alternative Oil Seed For the Preparation of a Local Food Seasoning SO Umeh1, SC Umerie2 and DO Amaefule1

1Department of Agricultural and Bioresources Engineering Nnamdi Azikiwe University, Awka, Nigeria 2Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria

ARTICLE INFO

ABSTRACT

Received: Revised: Accepted:

July 23, 2013 August 12, 2013 August 19, 2013

Cassava seed, a major waste in an agricultural farm, was utilized in this work as a raw material for the production of a fermented food seasoning ‘ogiri’. Proximate analysis, trace metal and organoleptic tests were performed on the fermented product. The product was found to have 40 % moisture, 5 % ash, 8 % crude fibre, 19.6 % crude protein, 13.7 % fat, and 28.5 % carbohydrate and 315.7 kcal/100 g energy content. Some trace elements present include calcium 2.77, iron 1.53, potassium 5.53 and sodium 2.01 mg / 100 g of the sample. Organoleptic qualities assessed by ten panellists, using the Kruskal Wallis test and the Likert scale confirmed the seasoning to show acceptability in taste, aroma and texture.

Key words: Cassava (Manihot esculenta Crantz) seeds, Fermentation, Food seasoning

*Corresponding Address: Umeh SO, [email protected]

Cite This Article as: Umeh SO, SC Umerie and DO Amaefule, 2013. Cassava seeds as alternative oil seed for the preparation of a local food seasoning. Inter J Appl Sci Engr, 1(2): 69-72. www.ijapscengr.com

INTRODUCTION

The tropical root crop, Cassava (Manihot esculenta

Crantz) of the family Euphorbiceae is a perennial shrub with an edible starchy root, which grows in the tropical and sub–tropical climates (Burrell, 2003).

It is a staple part of the diet in Africa and elsewhere, and was estimated by IITA in 1990 that the crop provides about 40% of all the calories consumed in Africa and ranks second only to cereal grains as the chief source of energy in Nigerian diet.

By this, cassava plays an important role in alleviating food crises in Africa, though poor in protein (1.2 %) and contains cyanide (>10 mg / 100 g fresh weight) in some varieties (Nwabueze and Odunsi, 2006).

In many regions of the tropics, it serves as one of the basic food sources for about 200–300 million people and some animals. In 1999, Nigeria produced 33 million tonnes of cassava, making her the World’s largest producer of cassava (Sobowale et al., 2007).

In Africa and some parts of Latin America, it is mostly used as food for human consumption, while in Asia and other parts of Latin America; cassava is used mainly commercially for the production of animal feeds and other starch–based industrial products (FAO, 2002). The root tubers of cassava can be processed into garri, fufu,

ketonte, chickwangue, etc. (Okafor, 1981; Umeh and Odibo, 2013).

Other products include starch for domestic and industrial purposes and cassava flour (Umeh et al., 2007). The tubers can also be used industrially for the production of ethanol.

Cassava stems are used for vegetative propagation, while the leaves are consumed as vegetables in some parts of the world and have been found to be good sources of vitamins A and B (Oyewole, 2002).

Flowering in cassava is frequent and regular in some cultivars like the bitter cassava. The flowers are borne on the terminal panicles, with the axis of the branches being continuous with that of the panicle inflorescence.

Crop pollination is done through the flowers by insects. After pollination and subsequent fertilization, the cassava ovary develops into the young fruit. It requires 3–5 months after pollination for the fruit to mature.

The mature fruit is a capsule, globular in shape, with a diameter of 1–1.5 cm. The endocarp is woody and has three lobules, each containing a single seed. The fruit is dehiscent or explosive after maturity (Dutta, 1989).

Cassava seeds are similar to castor oil (Ricinus communis) seeds but relatively smaller. They are mere farm wastes since the stems are planted vegetatively to raise new plants. They contain oil which can be used for

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the production of soap and other cosmetic products (Ajiwe et al., 1994).

Proteinous oil seeds like castor oil seeds (Ricinus communis), melon seeds (Citrullus vulgaris) and fluted pumpkin seeds (Telferia occidentalis) apart from serving as source of fats and oils, have been processed by cooking and microbial fermentation into a local food seasoning called ‘Ogiri’(Igbo) (Eka, 1980, Nzelu 2006).

The Hausa and Yoruba tribes of Nigeria call their counterpart fermented condiments ‘Dawadawa’, and ‘Iru’ respectively. These local seasonings are important for the preparation of different types of meals in Nigeria.

Among the Igbos, it is highly prized and is almost inevitable in the flavouring of some traditional soups including ‘onugbu’ (Veronia amygdalina), ‘oha’ (Pterocarpus soyanxii), ‘egusi’ (melon) and ‘nsala’ soups.

It is usually employed in small proportions in these food preparations but indispensable. It does not only enrich the soups with proteinacious meaty taste, it also gives some health benefits (Nzelu, 2006).

Most commercial seasonings including maggi are expensive due to the high cost of the raw materials used for their production. While castor seeds and melon seeds are also costly, the seeds of fluted pumpkin are very scarce and in short supply.

Cassava materials contain cyanide and other antinutritional factors which are drastically reduced by the fermentation and cooking processes (Eka, 1980). Thus the aim of this work is to utilize cassava seeds as an alternative oil seed for the production of a local food seasoning.

MATERIALS AND METHODS

Cassava seed samples

Matured brownish–green fruit capsules bearing four encapsulated seeds were collected (hand–picked) from a farm in the premises of Nnamdi Azikiwe University, Awka, Anambra state, Nigeria. The fruits were dried for four days and the seeds removed from the capsule. The hard seeds were further dried for the next four days and then dehulled. Production of Cassava seed ‘ogiri’

500g of the dehulled seed samples were cleaned, broken into small bits and soaked in water for 48 hours.

The seeds were washed with tap water and wrapped with three layers of fresh heat–wilted banana leaves and tied with strings. The seed–bundle was put in a clean pot, enough water added and cooked for 5 hours. The bundle was removed from the pot, punctured severally to drain off water and placed over a fire place with regular turning.

Fermentation was allowed to take place for 2 days, after which the samples were unwrapped and mashed into a paste. Salt was added to improve the taste. The salted product was put in a clean plate and covered with clean foil (and wilted banana leaves) and allowed to further ferment for another 2 days. The flow chart below showed the process involved in the cassava ‘Ogiri‘ production. Chemical analysis

The chemical and mineral compositions of the fermented cassava seed product were determined on the

second day of fermentation after mashing. Crude protein content was determined using the micro Kjeldahl method described by Pearson (1976). Percentage moisture, ash, crude fibre, fat, carbohydrate and gross energy contents were determined using the AOAC method of 1980. Atomic adsorption spectroscopy (AAS) method as outlined by Williard et al., (1974) was used to determine the trace mineral elements of the product. The Grignard test as described by Okafor et al., (1998) and used by Umeh and Odibo (2013) was used to check the cyanide content. Glutamic acid content was determined by paper chromatography using the method of Padmaja et al. (1994). Calculation of the amount of glutamic acid was done using Beer Lambert’s law as described by Plummer (1979). The antinutritional factors, Tannin and Oxalate were determined using the standard methods of Boyd (1976) and Liener (1980).

Cassava seed ↓ Drying for 4 days ↓ Breaking to remove the capsules ↓ Sun drying for 4 days ↓ Dehulling ↓ Broken into small bits ↓ Soaking overnight (48 h.) ↓ Washing ↓ Wrapping ↓ Cooking for 5 hours ↓ Drying ↓ Fermentation (2 days) before mashing ↓ Mashing then fermentation (2days) ↓ ‘Ogiri’

Fig 1: Flow chart for the cassava ‘Ogiri’ production Determination of the organoleptic qualities of the cassava ogiri

The sensory evaluation of the aroma, texture and taste of the freshly produced fermented product was carried out. The rating method was used and ten panellists who are conversant with the aroma, texture and taste of such products were chosen. Each of the panellists was given a sample of the product and asked to comment on how much he/she liked or disliked the product by rating the sample as excellent–5, very good–4, good–3, fairly good–2, bad–1 and very bad–0. The result of the test was assessed using the LIKERT scale. The scores for the samples were analyzed statistically using the Kruskal–

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Wallis test (Umeh and Odibo, 2013). Using the Decision Rule, accept the null hypothesis if the average computed response is less than 2.5 and accept the alternative if the same response is more than 2.5.

RESULTS

The fermenting mash yielded a product with a very

pleasant ‘ogiri’ taste on the second day. Table 1 showed the chemical composition of the fermented product and that of the castor oil seed ‘ogiri’ as found by Nzelu (2006). Table 2 contains the result of the mineral composition of the product, the seasoning showed the presence of some mineral supplements that are good in body building such as calcium, potassium etc. Table 3 contains the result of the antinutritional factors (tannin and oxalate) found while Table 4 showed the result of the organoleptic qualities of the cassava seed ‘ogiri’. Table 1: The chemical composition of the fermented product and castor oil seed ogiri 100 g of the sample

Sample Cassava ‘ogiri’ *Castor ‘ogiri’ % Moisture 40.0 45.0 % ash 5.0 2.25 % crude fibre 8.0 6.0 % protein 19.6 12.25 % fat 13.7 5.0 % carbohydrate 28.5 39.5 Gross energy (kcal/100g) 315.7 253 Glutamic acid (mg/100g) 0.12 – *Nzelu, 2006

Table 2: Mineral composition of the fermented product

No. Parameters mg/100g 1 Calcium 2.77 2 Iron 1.53 3 Potassium 5.53 4 Sodium 2.01

Table 3: Antinutritional factors found in the product

No. Parameters mg/100g 1 Tannin 0.0152 Oxalate 0.033 3 Mercury 0.000 4 Cyanide 0.000

Table 4: Scores of organoleptic qualities of the product

No. Parameters Score Inference 1 Aroma 4.5 excellent 2 Taste 4.0 very good3 Texture 4.3 very good

DISCUSSION

The product has a high moisture content of 40%.

High moisture content is a characteristic feature of such local seasonings including soya ogiri 65 % and castor oil ogiri 45 % (Nzelu, 2006) and can be reduced by drying the product in the oven without losing its organoleptic qualities (Achi, 2005).

The product has low ash content, thus translating to higher organic components of the product (Ogueke and Nwagwu, 2007). The protein content of the product is appreciable and can add to the protein of the food preparations, hence a good protein supplement for both

adults and children. The value exceeds those of soya bean ogiri and castor oil seed ogiri of 12.5 % and 13.2 % respectively (Nzelu, 2006; Achi, 2005), and also exceeds that of ‘maggi’ cube of 10.27 % (Eka, 1984).

The food seasoning has a low fat content (13.7 %) and consequently low in cholesterol. This value falls within the range for the same type of soup condiments prepared from oil seeds like melon 20 %, castor oil seed 30 %, ‘okpei’ 12.5 % and ‘dawadawa’ 15 % (Enujiugha, 2009).

The fibre, carbohydrate and gross energy contents make it an easily digestible energy supplement. The product contains some mineral elements useful for tissue and bone development such as iron, calcium, sodium and potassium. Paper chromatography of the fermented product showed the presence of glutamic acid which is the main flavour enhancer in food condiments. The amount of glutamic acid can be compared with that of maggi cube which is 112.5 umoles/g dry samples (Eka, 1984). It could be noted that glutamic acid when consumed in high concentrations have been found to cause nervous disorder particularly brain damage (Oney, 1980).

The low glutamic acid content of the product makes it suitable for safe consumption. All the antinutritional factors are below the tolerable dose for man and animals. Tannin content (0.015 mg /100 g) of the fermented product is below the acceptable range for man and animals. Boyd (1976) reported that the acute lethal dose (LD50) of tannin in 50% test population for mice is 3.50 g / kg and rabbit 5.0 g / kg body weight. Hodgson and Gutherie (1980) reported that the acceptable tannin intake for humans is in the order 560 mg per day. Hence the fermented cassava product had its tannin content within normal limits for man and animals. The oxalate content was in trace when compared with other plant seeds. Some plant materials contain appreciable amount of oxalate for example spinach 19.74 %, cucumber 0.57 % and okro 0.28 % (Munro and Bassir 1969), hence the oxalate of the product can be tolerated. There is no trace of cyanogenic glycoside in the product.

This has been detoxified by the soaking of the seeds, cooking and fermentation processes (Eka, 1980; Eka, 1984; Achi 2005). Conclusion

A local food seasoning ‘ogiri’ was successfully prepared from the seeds of cassava plant (Manihot esculenta, Crantz). A very pleasant aroma ogiri was produced which was confirmed by the ten panellists that tested the product and confirmed it as ‘ogiri’. Hence cassava seed which has been considered as agricultural waste can now be utilized in the production of a local food seasoning. This will be economically beneficial to Nigerian families because of its availability and abundance. Drying of the produced ‘ogiri’ in an oven to reduce the moisture content will likely improve the quality and shelf life.

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