Sarajevo College Graduation Work
TURKISH – BOSNIAN SARAJEVO COLLEGE
Bosna Sema Educational Institutions
TOPIC :ACIDS IN FRUITS AND VEGETABLES
Mentor: Student:
Selami Bingöl, prof. Melisa Čehajić, IV
Sarajevo, 2014. godine
1
Sarajevo College Graduation Work
CONTENTS
- CONTENTS…………………………………………………………………..1
1. INTRODUCTION……………………………………………………………2
1.1. Acids……………………………………………………………………
…2
1.2. Fruits and
vegetables………………………………………………………2
1.3. Why this topic?......................................................................................3
2. EXPLAINING THE TOPIC…………………………………………………3
2.1. Acids and
fruits…………………………………………………………….3
2.2. Acids and
vegetables………………………………………………………5
2.3. About fruit and vegetable
acids……………………………………………5
2.3.1. Citric acid…………………………………………………………...6
2.3.2. Malic acid…………………………………………………………..7
2.3.3. Tartaric acid…………………………………………………………9
2.3.4. Succinic acid……………………………………………………….10
3. CONCLUSION……………………………………………………………….12
4. REFERENCES……………………………………………………………….13
5. COMMENTS…………………………………………………………………14
2
Sarajevo College Graduation Work
1. INTRODUCTION1.1. Acids
An acid is a chemical substance whose aqueous solutions are characterized by a sour taste,
the ability to turn blue litmus red, and the ability to react with bases and certain metals
(like calcium) to form salts. The pH scale is a ranking of acidity. The "p" stands for potenz,
meaning potential to be, and the "H" is for hydrogen. Aqueous solutions of acids have
a pH of less than 7. A lower pH means a higher acidity, and thus a higher concentration
of hydrogen ions in the solution. Chemicals or substances having the property of an acid are
said to be acidic.
Picture 1., PH value of common substances
3
Sarajevo College Graduation Work
1.2. Fruits and vegetables
The primary chemical constitution in mist freshly harvested fruits and vegetables is
water, which ranges from low of 65% (fresh weight) in persimmons to a high of 96% in
cucumbers. Fruits and vegetables tend to be low in protein and lipids and high in
carbohydrates.
Fruits and vegetables are also one of the major sources of different useful acids. Humans and
many animals have become dependent on fruits as a source of food.
1.3. Why this topic?
Acids are all around us, they are the main components of most food that we consume in our
daily life. They can be very useful when consumed properly, conversely they can be harmful
when not consumed the way they must be consumed. Furthermore, in order to keep ourselves
healthy, we must consume fruits and vegetables. As we said before, they are sources of acids.
Some people may have problems with fruit and vegetables because of their acid content.
That’s why we must be aware of all good and bad sides of those acids, and also we must
know right way to consume them. Besides all this, next sections will be based on acidic fruits
and vegetables in Bosnia and Herzegovina, since BiH is rich in many different kinds of food.
Unfortunately, due to lack of information, many of them are not used the way they should be.
In this work, we will talk exactly about those acids, in both fruits and vegetables. By tables
and diagrams, this topic will be better explained, and, hopefully, platform for better usage of
our plants.
2. EXPLAINING THE TOPIC
2.1. ACIDS AND FRUITS
4
Sarajevo College Graduation Work
Acid fruits are the most detoxifying fruits and excellent foods. Study of acids present in fruits
is very important since some people may have problems due to fruit acids. In the table below,
we can see presence of certain acids in different fruits.
Type Predominant Acids1 Present
Apples Malic, quinic, aketoglutaric, oxalacetic, citric, pyruvic, fumaric, lactic and succinic acids
Apricotes Malic and Citric acids
Avocados Tartaric Acid
Bananas Malic, citric, tartaric and traces of acetic and formic acids
Bilberry Citric
Blackberries Isocitric, Malic, lactoisocitric, shikimic, quinic, and traces of citric and oxalic acids
Blueberries Citric, malic, glyceric, citramalic, glycolic, succinic, glucuronic, galacturonic, shikimic, quinic, glutamic
and aspartic acids
Boysenberries Citric, malic, and Isocitric acids
Cherries Malic, citric, tartaric, succinic, quinic, shikimic, glyceric and glycolic acids.
Crabapple Malic
Cranberries Citric, malic and benzoic acids.
Currants Citric, tartaric, malic and succinic acids.
Elderberries Citric, malic, shikimic and quinic acids.
Figs Citric, malic and acetic acids.
Gooseberries Citric, malic, shikimic and quinic acids.
Grapefruit Citric, tartaric, malic and oxalic acids.
Grapes Malic and tartaric (3:2), citric and oxalic acids.
Kiwifruit Citric
Kumquat Citric
Lemons Citric, malic, tartaric and oxalic acids (no Isocitric acid)
Limes Citric, malic, tartaric and oxalic acids.
Loganberry Malic, citric acids
Nectarine Malic
Orange peel Malic, citric and oxalic acids.
Orange Malic and oxalic acids
Passionfruit Malic
Peaches Malic and citric acids
Pears Malic, citric, tartaric and oxalic acids
Pineapples Citric and malic acids.
Plums Malic, tartaric and oxalic acids.
Raspberry Citric
Rosehip Malic
Quinces Malic acid (no citric acid)
1 Acids which occur in appreciable quantities are shown in italics. The relative amount of each varies widely withthe variety, degree of ripeness and seasonal influences. Complete identifications of all the acids present in manyof the products is obviously lacking in many instances.
5
Sarajevo College Graduation Work
Salad Citric and malic
Strawberries Citric, malic, shikimic, succinic, glyceric, glycolic and aspartic acids.
Tangerine Citric
Youngberries Citric, malic and Isocitric acids.
Table 1., Fruits' types an acids present in fruits
2.2. ACIDS AND VEGETABLES
Acids in vegetables are not as present as those in fruits, but it is important to know which
vegetables are most acidic, since those acids may be used for many different purposes. In
table below, we will learn acidic vegetables and name of their acids.
Type Predominant Acids2 Present
Beans Citric, malic and small amounts of succinic and fumaric acids
Broccoli Malic and citric (3:2) and oxalic and succinic acids.
Carrots Malic, citric, Isocitric, succinic and fumaric acids.
Mushrooms Lactarimic, cetostearic, fumaric and allantoic acids.
Peas Malic acid.
Potatoes Malic, citric, oxalic, phosphoric and pyroglutamic acids.
Rhubarb Malic, citric and oxalic acids.
Tomatoes Citric, malic, oxalic, succinic, glycolic, tartaric, phosphoric, hydrochloric, sulphuric, fumaric,pyrrolidinonecarboxylic and galacturonic acids.
Table 2., Vegetables' types an acids present in vegetables
With help of these tables, we came to conclusion that there are fruits and vegetables that
contain only one type of acid, but there are also those who contain many different acids.
Using only this table, we may learn only list of acids, but not their structures, applications, or
effects on our health. In order to learn all this, we have to examine every type of fruit and
vegetable acid.
2.3. ABOUT FRUIT AND VEGETABLE ACIDS
To summarize, the most common fruit and vegetable acids are:
2 Acids which occur in appreciable quantities are shown in italics. The relative amount of each varies widely withthe variety, degree of ripeness and seasonal influences. Complete identifications of all the acids present in manyof the products is obviously lacking in many instances.
6
Sarajevo College Graduation Work
a) Citric
b) Malic
c) Tartaric
d) Succinic
2.3.1. CITRIC ACID
Citric acid is a natural, weak organic acid that is found in many fruits and vegetables,
especially citrus. Because citric acid is also a byproduct of the citric acid cycle, it is also
produced by many living organisms, including mold. Lemons, oranges, limes, and other
citrus fruits possess high concentrations of citric acid. Citric acid is prized for its sour flavor,
preservative quality, and ability to act as a pH buffer. For these reasons, citric acid is found
on the ingredient list of many food products today. Within the European Union it is denoted
by E number E330.
How is Citric Acid Produced?
Although citric acid is found in high concentrations in many citrus fruits, it is not economical
to extract the acid from fruit for industrial use. Furthermore, the demand for citric acid far
outweighs the supply of citrus fruit available.
Uses for Citric Acid in Food:
- a flavor enhancer in beverages
- in soft drinks, teas, juices, and other beverages to create a slightly tart, refreshing
flavor and balance sweetness.
- as a preservative (added to jams, jellies, candy, canned foods, and even meat
products)
- in dry foods when a sour flavor is desired (when in powder form it's a dry
alternative to lemon juice or vinegar
7
Sarajevo College Graduation Work
- used to create an acidic environment and facilitate the ripening process when
making cheese, particularly mozzarella
- as a dietary supplement (added to vitamin supplements to make some vitamins
biologically available for absorption)
Citric Acid Availability
Citric acid can be purchased in powder form and is usually available in stores with other
home canning supplies. Citric acid may also be found in natural food stores or health food
stores with other vitamins and dietary supplements. In some grocery stores, citric acid is sold
in small shakers and labeled as "sour“ salt.
Citric acid has a formula C6H8O7.
Picture 2., structure of citric acid
2.3.2. MALIC ACID
Malic acid is a component of many of the foods that we eat daily. Although it is found as a
naturally occurring organic compound in various fruits, many choose to take malic acid
supplements to increase their overall health, as well as treat various maladies. Today, the acid
is most commonly used as a food additive and preservative. It is a mild and relatively
8
Sarajevo College Graduation Work
harmless acid when used in appropriate amounts. As a food supplement, it is generally
considered beneficial for health and is present in large amounts in apple juices. Malic acid,
when added to food products, is denoted by E number E296. As when taking any supplement,
however, you should not exceed the recommended amounts for consumption.
Uses of malic acid
- in pain reduction (frequently used by those who suffer
from fibromyalgia and chronic fatigue system)
- as energy boost (those who have it as a supplement to their diet, have experienced
a significant reduction in fatigue, giving them a much-needed boost of energy)
- in skin care (it is able to penetrate the skin more deeply, due to its chemical
composition, can greatly help in improving skin smoothness, pigmentation and
complexion)
Side Effects
Although generally regarded as a very safe and effective supplement, there can be some
minor side effects. The most common of these, while uncomfortable, are only experienced by
a small number of those who use the supplement. The side effects most frequently
experienced include muscle pain, nausea, redness, constipation, swollen skin, chest pain and
itching. While annoying, these typically dissipate after a couple days.
Foods Containing Malic Acid
9
Sarajevo College Graduation Work
The food that is most well known for its high malic acid content is the apple. Malic acid
contributes to the sourness of green apples. Other fruits with a very high concentration of the
acid are nectarines, cherries, lychees, bananas, mangoes, peaches, tomatoes and
strawbesrries. It can be found, however, in nearly all fruits.
Malic acid is also used as a flavor enhancer for many drinks and candies. It is especially
common in diet sodas and other artificially sweetened drinks.
One of the greatest things about malic acid as both a food supplement and a skincare agent is
the fact that it is a completely natural, organic compound.
Malic acid has a structural formula HO2CCH2CHOHCO2H.
Picture 3., structure of malic acid
2.3.3. TARTARIC ACID
Tartaric acid is a white crystalline diprotic aldaric acid, solid at room temperature. Foods
such as grapes, apricots, avocados, apples and sunflower seeds have all been known to have
high concentrations of the acid. Alternatively, it has also been found in tamarinds which are a
type of tree indigenous to tropical Africa and other warms parts of the world. The acid is said
to act as both an antioxidant and an anti-inflammatory which can help bolster the immune
system and promote overall wellness. Salts of tartaric acid are known as tartrates. It is a
dihydroxyl derivative of succinic acid.
10
Sarajevo College Graduation Work
Uses of malic acid
- As a leavening agent (when combined with baking soda)
- In wine-making (used during the fermentation process for acidity adjustments to
make for a more palate pleasing taste)
- as a natural preservative for things like soft drinks, fruit juices, candies and certain
types of jams
- used in the preparation of cement
- in the cosmetic industry
Side EffectsAs is the case with many naturally occurring acids, over-consumption can result in unpleasant side effects. While it’s unlikely that overeating foods that contain the acid will cause such side effects, those supplementing the acid in its crystalline form are at risk. Such side effects of over-consumption include increased thirst, vomiting, diarrhea, abdominal pain and gastrointestinal inflammation.
Tartaric acid has a structural formula HO2CCH(OH)CH(OH)CO2H.
Picture 4., structure of tartaric acid
2.3.4. SUCCINIC ACID
Succinic acid (butanedioic acid) historically known as spirit of amber) is a diprotic,
dicarboxylic acid . It is a white, odorless solid. It plays a significant role in intermediary
metabolism (Krebs cycle) in the body. The name derives from Latin succinum,
11
Sarajevo College Graduation Work
meaning amber, from which the acid may be obtained. Succinic acid is created as a byproduct
of the fermentation of sugar. It lends to fermented beverages such as wine and beer a
common taste that is a combination of saltiness, bitterness and acidity. Succinic acid is an
important biochemical intermediate that occurs in all living creatures. Like other simple
mono- and dicarboxylic acids, it is not considered dangerous, although it is a skin irritant.
Amber gems are believed to be a very powerful anti-oxidant that may help fight toxic free
radicals and disruptions of the cardiac rhythm, succinic acid has been shown to stimulate the
neural system recovery and strengthens the immune system, it also known to help
compensate for energy drain in the body and brain, boosting awareness, concentration and
reflexes, and reducing stress.
Uses of succinic acid
- Flavoring agent for food and beverages;
- Intermediate for dyes, perfumes, lacquers, photographic chemicals, alkyd resins,
plasticizer,
- Metal treatment chemical,
- in vehicle water cooling systems and coatings.
- in Medicines of sedative, antispasmer, antiplegm, antiphogistic, anrhoter,
contraception and cancer-curing.
Succinic acid has a structural formula HOOC-(CH2)2-COOH.
Picture 5., structure of succinic acid
12
Sarajevo College Graduation Work
3. CONCLUSION
At previous pages, we observed acids in fruit and vegetables, and also explained the most
important acids. We learned both positive and negative effects they can have on our health or
environment. At the end we may conclude that the study of acids, especially in fruits and
vegetables is very important for our daily life, since we use them very often. In Bosnia and
Herzegovina, many different types of fruits and vegetables may be found, but, knowing the
fact that we are not so aware of acid contents within them, we can say that our fruits and
vegetables are not fully used. By studying them more detailed, we can improve our
agriculture and our economy too. Many new natural-based medicines can be made, and many
negative effects may be avoided. We are not aware of importance of acids. Furthermore,
internet sites or books don’t give us so much information about acids. That shows us that
study of acids in fruits and vegetables should be improved and information about it should be
spread among the people.
13
Sarajevo College Graduation Work
4. REFERENCES
http://foodreference.about.com/od/Food-Additives/a/What-Is-Citric-Acid.htm (18.3.2014.)
http://acidpedia.org (7.4.2014.)
http://www.chemspider.com (9.4.2014.)
http://www.hawkinswatts.com.au/documents/Natural%20Acids%20of%20Fruits%20and
%20Vegetables.pdf (5.2.2014.)
http://en.wikipedia.org
http://www.tehnologijahrane.com/hemijahrane/kiseline (14.3.2014.)
14
Sarajevo College Graduation Work
COMMENTS
________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
15
Sarajevo College Graduation Work
________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Date of submission of work: __________
Date of defense work: ____________
Mark: ________________________________
Members of the commission:
1. ______________________________________
2. _______________________________________
3. _______________________________________
16