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

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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

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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

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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

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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.

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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.

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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

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- 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

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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

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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.

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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,

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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

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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.

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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.)

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COMMENTS

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________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Date of submission of work: __________

Date of defense work: ____________

Mark: ________________________________

Members of the commission:

1. ______________________________________

2. _______________________________________

3. _______________________________________

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