Introduction

2. Classification of fresh fruits and vegetables. Characteristics of individual species

3. Transportation and acceptance of fresh fruits and vegetables

4. Processes occurring during the storage of fresh fruits and vegetables

5. Factors affecting preservation food products

Conclusion

Bibliography

Introduction

In this work, I examined the chemical composition and nutritional value of fresh fruits and vegetables, their classification and characteristics of individual species. Processes that occur during the storage of fresh fruits and vegetables. Factors affecting the safety of food products.

I studied the composition of many fruits and vegetables, as well as the presence in them of such vital vitamins for the human body as:

• Vitamin C
• Vitamin A
• Vitamin B
• Vitamin B1
• Vitamin B2
• Vitamin D
• Vitamin E.

She spoke about the important role of organic acids, minerals, carbohydrates, proteins, fats.

1. Chemical composition and the nutritional value fresh fruits and vegetables

All fruits and vegetables contain a large amount of water (about 75% - 85%). The exception is nut fruits, which contain on average only 10% - 15% water. Moisture in fruits and vegetables is both free and bound.

Bound moisture is removed to a lesser extent and partially retained during drying.

Free moisture is a good breeding ground for putrefactive bacteria and microbes, so fruits and vegetables containing a large amount of free moisture cannot be stored for a long time and need to be processed. Fruits and vegetables are the main suppliers of carbohydrates. These are mainly monosaccharides (glucose, sucrose), disaccharides (sucrose), polysaccharides (fiber, pectin substances).

Pectin substances and cellulose on properties belong to ballast substances.

In addition to carbohydrates, the chemical composition of fruits and vegetables includes polyhydric alcohols (sorbitol and mannitol), which have a sweet taste. They are contained in large quantities mountain ash, plum, to a lesser extent - in apples.

The sucking of fruits and vegetables also includes nitrogenous substances - proteins, amino acids, enzymes, nucleic acids, nitrogen-containing glycosides. The largest amount of proteins falls on olives (7%), legumes (5%), potatoes (2-3%), and nuts. Most fruits and vegetables contain less than 1% protein.

Fruits and vegetables are the main suppliers of enzymes.

1. Classification of fresh fruits and vegetables. Characteristics of individual species

When classifying fruits, two main features are used - a sign of structure and a sign of origin.

According to the structure, they distinguish:

• Pome fruits (apples, mountain ash, pear, quince); they all have a skin, inside the fruit there is a five-celled chamber containing seeds;
• Stone fruits - their structure is characterized by the presence of a skin, fruit pulp and a drupe containing a seed; stone fruits include plums, cherries, apricots, peaches, etc.;
• Berries - this group is divided into 3 groups: real berries, false and complex. For real berries currants, grapes, gooseberries, cranberries, blackberries, lingonberries, blueberries. In real berries, the seeds are immersed directly in the pulp. False berries include strawberries and strawberries. Their seeds are located on the skin. Complex berries consist of many small berries fused on one fruit. This group includes raspberries, blackberries, stone fruits and cloudberries;
• Nut fruits, which are divided into real nuts (hazelnuts) and stone fruits ( walnuts, almonds). All nut fruits consist of a kernel enclosed in a woody shell. On the surface of stone nuts there is a green pulp, which gradually darkens and dies off as it ripens.

By origin, the fruits are divided into subtropical (among them there is a group of citrus fruits) and tropical. Many subtropical and tropical fruit require a high storage temperature, and at cold temperatures they catch cold and freeze. So, for example, bananas can be stored at a temperature not lower than +11 degrees. Pineapples - not lower than +8 degrees.

Fresh vegetables are divided into 2 groups: vegetative and generative, or fruit and vegetable. Vegetables in which leaves, stems, roots and their modifications are used as food are vegetative. And vegetables in which the fruits are used for food are called generative.

Among vegetative vegetables, depending on the part used in food, there are:

• tuberous (potato, bata, Jerusalem artichoke);
• root crops (beets, radishes, carrots, radishes, turnips, parsley, rutabaga, celery, parsnips);
• leafy vegetables (white cabbage, kohlrabi, cauliflower, brussels, savoy);
• onion vegetables(onion, onion - prey, batun, garlic);
• lettuce-spinach (spinach, lettuce, sorrel);
• spicy vegetables (tarragon, basil, cilantro, dill, celery);
• dessert (artichoke, asparagus, rhubarb).

Generative vegetables are divided into the following subgroups:

• tomato (tomatoes, eggplant, pepper);
• pumpkin (cucumbers, pumpkin, zucchini, melons, watermelons, squash);
• legumes (peas, beans, beans);
• grain vegetables (sweet corn).

1. Transportation and acceptance of fresh fruits and vegetables

When transporting fresh fruits and vegetables, it is necessary to comply with specific requirements due to their properties. In particular, transportation of fresh fruits and vegetables without packaging is not allowed. Some fruits and vegetables (potatoes, cabbage, beets) are transported in bulk during mass harvesting. When transporting watermelons without packaging, it is necessary to sling them with straw.

During the acceptance of fresh fruits and vegetables, their quality is assessed by general and specific indicators in accordance with the current instructions. General indicators include appearance and size. Deviations in size are allowed only within the normal range.

Specific metrics include:

• The degree of maturity, which is divided into consumer, volumetric and physiological. Cucumbers are sold only at the consumer degree of maturity, the physiological degree of maturity is not allowed. For some fruits (apples of late varieties), the volumetric physiological degree of maturity is the same;
• Taste and smell;
• The density of the bunch, the presence of non-whole brushes, the number of crumbled berries;
• Humidity (determined only for nuts);
• Consistency (for bananas and oranges).

During the acceptance of fruits and vegetables, sorting is carried out, while the following quality categories are distinguished:

• Standard fruits and vegetables - meet the requirements of current standards; this also includes defective fruits and vegetables within tolerances;
• Non-standard fruits and vegetables with defects, limited by acceptable standards, but in excess of established norms;
• Waste with defects not allowed by the standards.

1. Processes suitable for storing fresh fruits and vegetables

During storage, various physical and biological processes occur in fruits and vegetables, such as evaporation of moisture, respiration, ripening, healing and thickening of the skin, hydrolytic decomposition of complex organic substances.

Respiration is the most important biochemical process and serves as a source of energy for metabolic processes. Respiration is accompanied by a loss of mass of fruits and vegetables, the release of energy, heat and moisture. In the process of respiration, there is a change in the gas composition of the environment surrounding the product, significant losses in both the quantity and quality of fresh fruits and vegetables.

The intensity of the breathing process depends on the type of fruits and vegetables, their physiological state (degree of maturity, freshness, presence of damage, moisture content) and storage conditions (temperature, light and gas composition of the environment).

Respiration can be oxygenated (aerobic) or anoxic (anaerobic).

Hydrolytic processes: under the influence of enzymes, hydrolysis occurs, and always in the presence of water.

1. Factors affecting food safety

fruit vegetable nutritional value

Temperature is one of the most important conditions food storage. Temperature affects the intensity of all processes. As the temperature rises, water evaporation increases, enzyme activity increases, chemical reactions accelerate, and conditions are created for the development of pests.

The optimum temperatures for different products are different. Their range ranges from -18 to +25 degrees. For most products, freezing almost completely eliminates the occurrence of harmful chemical processes, although there are those for which the optimum temperature is from 0 to +4 degrees and its fluctuations are highly undesirable.

Air humidity. This factor is closely related to temperature. The choice of relative air humidity depends on the product. Dry foods require low humidity (65-70%), high moisture foods require 85 to 90% humidity.

Gas environment. The increased content of oxygen in the gaseous medium and its contact with the product lead to the oxidation of fats (staff), to a change in the color of wines. The gas composition of the medium can be changed. Oxygen must be excluded from the composition of the gaseous medium. The inclusion of inert gases in the gas composition of the medium, on the contrary, has a positive effect on the storage of many products.

Most often, a controlled atmosphere is used when storing fresh fruits and vegetables. In it, the proportion of oxygen decreases, and the proportion of carbon dioxide increases. This leads to a delay in the processes of ripening and overripening, a decrease in the activity of microbiological diseases, and the consistency of products is better preserved.

In addition to the controlled gas environment, a modified gas environment is used. It involves the use of polymer films with a selective medium.

Light. Almost all food products require the absence of light. For example, when potatoes are stored in the light, a toxic green substance, corned beef, is formed on the surface of the tubers. Light destroys vitamins, negatively affects the properties of colored products, especially when using natural dyes.

Ventilation is most relevant when storing plant products. There are natural, artificial and forced ventilation. The latter is used in modern vegetable stores and provides better food preservation.

sanitary regime. It includes activities for disinfection and pest and rodent control.

The quality of packaging materials.

6. Nutritional value of fruits and vegetables

The nutritional value and organoleptic (taste and aroma) properties of vegetable fruits are determined by the chemical substances of which they are composed.

The composition of plant products includes proteins, fats, carbohydrates, vitamins, organic acids, minerals and trace elements.

The predominant component of all raw materials is water. Its fruits contain 75-90%, and vegetables - 65-96%.

Squirrels. Protein substances play an important role in human nutrition. The main sources of protein are meat and fish. In vegetables and fruits, the protein content is relatively low. However, due to the special importance of protein nutrition herbal products should be used as an important supplemental protein source.

Fats are important in nutrition. The fat content in the tissues of fruits and vegetables is very low; in significant quantities they are contained in the seeds. Vegetable oils contain essential linoleic and linolenic acids, which have a greater biological value and are better absorbed by the body than animal fats.

Carbohydrates are an energy material and serve as a reserve nutrient for the human body. From vegetable raw materials, fruits are especially rich in carbohydrates. They contain carbohydrates mainly in the form of various sugars (sucrose, glucose, fructose) and starch. The main part of carbohydrates in normal nutrition enters the body in the form of starch, and only a small part - in the form of sugar. Starch in the body turns into glucose, which is absorbed into the blood and nourishes the tissues of the body.

Vitamins are substances necessary for the normal functioning of the human body. They increase the efficiency and resistance of the body to infectious diseases, have a positive effect on its growth and development.

Vitamin C is an antiscorbutic agent and is essential for proper growth and development of the body.

The main source of vitamin C is vegetables, fruits, berries, rosehips, blackcurrants, lemons, oranges, etc.

Vitamin A is one of the most important and widespread, ensuring the normal growth of the body. The lack of this vitamin in the human body lowers its immunity to various infections.

In its free form, vitamin A is found only in the liver fat of marine fish and whales. Vitamin A is absent in vegetable raw materials, but it contains provitamin A - carotene, from which vitamin A is formed during decay in the human body. Apricots, black currants, sweet red peppers, plums, carrots, spinach, red tomatoes and green peas are rich in carotene.

Vitamin B1 is found in almost all fresh fruits and vegetables, baker's and brewer's yeast. The absence or deficiency of this vitamin in the body causes a disorder of the nervous system.

Vitamin B2 is found in carrots - 0.005 - 0.01 mg per 100g, in cabbage, onions, spinach, tomatoes up to 0.05mg per 100g.

Vitamin D is extremely important for children, since its insufficient content in food leads to rickets. This vitamin is found only in animal products.

The richest source of vitamin D are fish fat, liver of animals and birds. Vitamin D is found in milk, butter, and egg yolks.

Vitamin E is widely distributed in nature, it is found not only in animal products, but also in many plant products. The germs of cereals and green leaves of plants are richest in vitamin E.

organic acids. All fruits and vegetables contain certain organic acids.

Organic acids play important role in metabolism. In the human body, they dissolve some unwanted deposits.

Meat and fish contain lactic acid. Malic, citric, tartaric and other acids are most common in fruits and vegetables.

Malic acid predominates in pome fruits, as well as dogwood, apricots, peaches, tomatoes and berries. Citrus fruits and cranberries contain a lot of citric acid. Tartaric acid is found in grapes. Sorrel and rhubarb are rich in oxalic acid.

Minerals. The main minerals are salts of calcium, sodium, potassium, iron, as well as sulfur, phosphorus and chlorine. Mineral salts are contained in the composition of every cell of a living organism. Without them, just like without water, life is impossible.

Iron salts are rich mainly in lettuce, cabbage, strawberries, apples, potatoes, peas, fish, meat, eggs; potassium salts - radishes, spinach, carrots, cabbage, oranges, lemons, tangerines. Proper and rational use of products, as well as the implementation of the recommended processing regimes during canning, allow almost completely preserving the nutrients and vitamins contained in them.

Conclusion

Having carefully studied the above material, I can draw the following conclusions.

Some fruits and vegetables have a large amount of moisture, therefore, they cannot be stored for a long time, because. moisture is a good breeding ground for putrefactive bacteria and microbes.

There are two main signs of fruit classification:

• By structure
• By origin.

During storage, various physiological and biological processes take place in fruits and vegetables, such as evaporation of moisture, respiration, ripening, healing and thickening of the skin.

The safety of fruits and vegetables is influenced by such factors as: temperature, air humidity, gas environment, light, ventilation, sanitary regime, quality of packaging materials.

Bibliography

1. Commodity research of food products Burova Marina - M .: "Prior Publishing House", 2000. - 144p.
2. home canning G.G. Tokarev. - D66 St. Petersburg: Polygon Publishing House LLC, 2004. - 220c.: ill.

Carbohydrates are the most important component of fruits and vegetables. Carbohydrates account for about 90% of the total dry matter content. Fruits and vegetables contain sugar, starch, fiber (from 0.3 to 4%). When some vegetables (beans, radishes, beans, cucumbers) ripen and overripe, the amount of fiber increases, which gives them a woody taste.

Starch accumulates in fruits and vegetables during their growth (in green peas, potatoes, sweet corn). As ripening, the mass fraction of starch in fruits decreases, in vegetables it increases.

Vitamins. Fruits and vegetables contain almost all currently known vitamins. Vitamin C (ascorbic acid) is found in vegetable peppers, in parsley; blackcurrant, wild rose, etc. As fruits and vegetables ripen, the amount of vitamin C increases, while storage decreases.

Carotene (provitamin A) - Carrots, tomatoes, leafy and green vegetables (lettuce, parsley, leeks), apricots, melons, peaches are rich in carotene.

Vitamin B 1 (thiamine) is found in legumes and cereals.

Vitamin B 2 (riboflavin) - in cereals, legumes and cabbage vegetables are relatively rich in them.

Folic acid - strawberries are the richest in folic acid. Folic acid is involved in hematopoiesis.

Minerals. The amount of minerals in vegetables and fruits varies from 0.25 to 2%. Vegetables and fruits are a valuable source of minerals in the diet. Vegetables and fruits contain calcium, iron, magnesium, sulfur, phosphorus, potassium, zinc, as well as iodine, cobalt, arsenic, copper and other trace elements.

Cabbage, leafy vegetables, carrots are rich in calcium salts.

Iodine is found in the largest quantities in persimmon, feijoa, oranges, bananas, green peas. Bananas, olives, blackberries, quince, cherries are rich in copper.

Coloring substances. The color of vegetables and fruits depends on chlorophyll, anthocyanins and carotenoids.

Chlorophyll colors vegetables and fruits in green color. Chlorophyll can only form in the presence of light. Spinach and nettle leaves are distinguished by a high content of chlorophyll. Anthocyanins color vegetables and fruits from red to dark blue. They accumulate in vegetables and fruits as they ripen. Anthocyanins have antibiotic properties and protect vegetables and fruits from damage by microorganisms.

Carotenoids are pigments that color vegetables and fruits yellow and orange.

In the human body, carotenoids play an important role, as they are the initial substances from which vitamins of group A are formed.

Tannins have an astringent, tart and slightly bitter taste. The high content of tannins in mountain ash, persimmon, dogwood, blackthorn (over 0.5%). Some tannins have antibiotic properties.

pectin substances. In vegetables and fruits, they are found in the form of protopectin (a water-insoluble substance) and pectin (a water-soluble substance). Pectin has colloidal properties: when heated with sugar and acid, it forms a jelly (gel).

Blackcurrant, gooseberries, some varieties of apples, citrus fruits, plums have the greatest gelling ability.

The gelling properties of pectin are widely used in confectionery production for marmalade, jelly, jam, marshmallow.

Essential oils (aromatic substances). They give fruits and vegetables their characteristic flavor. There are especially many aromatic substances in spicy vegetables (dill, parsley, tarragon), and from fruits - in lemons, oranges and other citrus fruits.

Essential oils are concentrated mainly in the skin of fruits and vegetables, they are few in the pulp. Maximum accumulation essential oils disappears as the fruit ripens. During storage and processing of fruits and vegetables, essential oils evaporate.

Phytoncides have bactericidal properties, have a detrimental effect on the microflora, releasing toxic volatile substances. The most active phytoncides are onion, garlic, horseradish. Phytoncides, protecting plants, increase their resistance to bacterial and fungal diseases.

Nitrogenous substances are found in vegetables and fruits in small quantities; most of them in legumes - (up to 6.5%), in cabbage (up to 4.8%).

When processing fruits and vegetables, nitrogenous substances can play a positive and negative role. In the production of wines, the presence of nitrogenous substances contributes to the development of yeast, better fermentation of juices. When cooking jam, if you do not remove the foam, mold may develop in it.

Fats. Most fruits and vegetables contain very little fat (0.1-0.5%). There are many of them in nut kernels (45-65%), in the pulp of olives (40-55%), as well as in apricot pits (20-50%), in sea-buckthorn berries (8%), in fruit seeds (23-60% ).

Fresh fruits and vegetables, as well as food products obtained from their processing, are of exceptional importance in the nutrition of people. They are a source of biologically valuable and vital compounds: minerals, essential amino acids, enzymes, vitamins, phytoncides. Many of their species are able to be stored for a long time without losing their nutritional value. Being everyday products of the diet, fruits and vegetables contribute to a more complete absorption of meat and dairy products, increase the resistance of the human body to colds, and contribute to longevity. With the help of fruits and vegetables, heart and stomach diseases, as well as diseases associated with impaired metabolic processes in the body, are treated. Most Products baby food produced from fruits and vegetables. The average annual consumption rates are (in kg): fruits - about 100; vegetables - 126; potatoes - 100-115.

Considerable attention is being paid to increasing the production of fruits and vegetables, which will be achieved through the implementation of a set of organizational and economic measures, which will make it possible by 1990 to bring the production of fruits in the country to 15 million tons, vegetables - to 41, potatoes - to 90-92 million. T.

Chemical composition of fruits and vegetables

The chemical composition of vegetables and fruits determines the most important indicators of their quality: appearance, taste, aroma, keeping quality, as well as nutritional value and calorie content. It is formed under the influence of soil and climatic conditions, varietal characteristics of fruits and vegetables and agricultural cultivation techniques. The chemical composition changes as fruits and vegetables grow and develop, reaching the optimal combination of individual chemicals during the ripening period.

Water is the main component of vegetables and fruits. Its fruits contain from 72 to 90%, and in vegetables and potatoes - from 65 to 96%. Organic and mineral substances are dissolved in it. During storage, fruits and vegetables lose water. This can have the most unfavorable effect on snoring, as withered tissues of fruits and vegetables lose their marketable appearance and are affected by diseases. Therefore, when storing fruit and vegetable products, it is necessary to observe conditions that prevent moisture loss.

Sakharov fruits and vegetables contain different amounts. In fruits, it varies from 0.5 (in lemons) to 25% or more (in grapes). In vegetables, they are much less - from 0.2 to 10-12%. In pome fruits, monosaccharides - glucose and fructose - predominate quantitatively. For this reason apple juice even with medium sugar content it seems sweet. Stone fruits, on the contrary, are richer in sucrose. Berries contain approximately the same amount of glucose and fructose - 3-4% each, and sucrose in them is less than 1%. In vegetables, the total content of soluble sugars varies within the following limits (in%): in onions - 3.5-12.2; in carrots - 3.3-12; in beets - 5.3-9.2; in cabbage - 1.5-4.5.

From monosaccharides fruits and vegetables contain glucose and fructose. From disaccharides- sucrose and trihalose (in mushrooms). Among polysaccharides starch, hemicellulose, cellulose, pentosans predominate, pectin substances are also included.

Starch is the most important storage carbohydrate. The largest amount of starch is found in potatoes (12-25 %) in unripe bananas (18-20 %). He is also in unripe apples, pears, tomatoes. When fruits ripen, starch is hydrolyzed into soluble sugars. Its hydrolysis also occurs in potato tubers in violation of the storage regime.

pectin substances in fruits and vegetables are represented by pectin, pectin acid and protopectin.

Pectin soluble in water; in the presence of sugars and organic acids, it forms a jelly, which is widely used in the manufacture of jams, marmalade, marmalade.

Pectic acid- a chemical compound less complex in structure, soluble in water.

Protopectin in chemical terms, it is the most complex among pectin substances. In the process of storing fruits and vegetables, it is gradually hydrolyzed with the formation of fiber and pectin.

Protopectin usually fills the intercellular spaces, linking the individual cells of the fruit pulp. As a result of its hydrolysis, the cells separate from each other and the pulp of fruits and vegetables softens. During storage of fruits and vegetables, the content of pectin substances in them gradually decreases. The conversion of protopectin to pectin can be slowed down by storing fruits at low temperatures (close to 0°C).

nitrogenous substances found in fruits and vegetables in small quantities and are represented mainly by amino acids and proteins. Among vegetables, green peas (up to 5%), as well as potatoes (up to 2%) and root crops - table beets and carrots, and from fruit crops - olives and nuts are the richest in protein. In fruits and vegetables, proteins are mainly part of the enzymes that regulate the metabolism during storage of these products. Daily consumption of potatoes in the amount of 300-400 G approximately 30% satisfies human needs for proteins.

organic acids in combination with sugars determine the taste of fruits and most vegetables. Usually, each type of fruit contains not one, but several organic acids with a predominance of one of them. So, in apples, pears and stone fruits, malic acid predominates, in citrus fruits - citric acid. Most vegetables (except sorrel) contain a lot of malic acid. Some acids (benzoic, salicylic, etc.) have bactericidal (antiseptic) properties, protecting fruits and vegetables from diseases. Organic acids oxidize faster during storage of fruits and vegetables than sugars during respiration. As a result, the fruits become tasteless or too sweet.

vitamins also found in fruits and vegetables. There are water-soluble and fat-soluble vitamins. Water solubles are found only in plant foods.

Among the water-soluble vitamins, the vital one is vitamin C(ascorbic acid). Fruits and vegetables are rich in vitamins group B(B, B L >, B:i, Bg, Bis), which are part of enzymes as an active group and play an extremely important role in regulating metabolic processes in the human body.

Vitamin U (anti-ulcer factor) V most found in cabbage vegetables.

Fruits and vegetables are rich carotene(provitamin A). In the human and animal body, it turns into vitamin A. Carrots, sweet peppers, parsley, sorrel, melons are rich in carotene, and sea buckthorn, apricots, peaches from fruits.

Minerals fruits and vegetables are the main source of minerals for humans. They are concentrated mainly in the cell sap. According to their quantitative content, they are divided into two groups: macro- and microelements.

TO macronutrients include: K, Ca, P, Na, Mg, CI, S, Fe; To trace elements- Pb, Cu, Zn, Mo, J, Co, Mn, etc. Macro- and microelements are part of the enzymes that regulate water and salt metabolism in the human body. In fruits and vegetables, minerals are in an easily digestible form for the body, and their total content ranges from 0.2 to 1.5%. Vegetables are richest in potassium, calcium, phosphorus, sodium, and iron.

Lipids and fats in fruits and vegetables are found in negligible amounts and are concentrated mainly in the seeds and skin of fruits. Skin lipids protect fruits from moisture loss.

Glycosides- These are complex organic compounds that often perform protective functions. In fruits and vegetables, they are concentrated in the skin and seeds. Many glycosides are bitter or spicy taste and specific smell. Most of them are poisonous to humans. The most common glycosides are:

amygdalin- in the seeds of bitter almonds, apricots, peaches, cherries, plums;

solanine- in the skin of potato tubers, unripe fruits of tomatoes and peppers;

capsaicin- in hot pepper;

limonin And naringin- in the peel and subcutaneous layer of citrus fruits;

sinigrin- in horseradish and mustard seeds.

Fruits and vegetables also contain dyes that determine their color and, consequently, their presentation. By chemical nature, most dyes are derivatives of phenol.

Chemical composition and nutritional value of vegetables

The chemical composition of vegetables includes organic and inorganic compounds, the quantitative and qualitative ratio of which determines their nutritional value.

The selection of a variety of vegetables and fruits in the daily diet improves metabolism and affects human health. The correct development and growth of children largely depend on the provision of their body with substances found almost exclusively in fruits and vegetables. In older people, due to the deterioration of metabolism, vegetables and fruits act as a kind of metabolic stimulant.

With the systematic consumption of fruits and vegetables, you can regulate the intake of vitamins, minerals and other biologically active substances into the body, thereby improving your condition or even curing yourself of one or another disease.

The absence of vegetables in the diet during the expedition to the North, long-distance travels has long led to metabolic disorders in the human body, which appeared in the form of scurvy, polyneuritis, anemia and other diseases.

The high water content causes, compared with other products, the low energy value of vegetables (with the exception of potatoes rich in starch), while the concentration of biologically active substances in vegetables - vitamins, microelements, antimicrobial substances, radiation-protective antiradiants, phenolic and other compounds - distinguishes vegetables into the most important food group. products needed for daily nutrition. The absence or deficiency of these substances leads to frequent illnesses, fatigue, lethargy and increased sensitivity to cold, blurred vision and other disorders in the human body. On the contrary, the presence of vegetables in the diet improves appetite, increases the secretion of gastric juice, which contributes to better digestion of food.

Vegetables, along with fruits, are considered primarily as a source of vitamins. The Science of Biologically valuable vegetables widely entered into everyday life. Today each housewife, mothers know that carrots are rich in provitamin A - carotene, but not everyone knows that this vitamin is absorbed almost completely only when consuming a product with fats.

The selection of vegetable crops is currently being directed by scientists not only to the development of new varieties that are distinguished by good palatability, high yield and frost resistance, but also high in vitamins and other bioactive substances.

The processing industry is challenged to identify better ways canning, to create "softer" technological regimes that allow to preserve biologically valuable substances to the fullest extent, to reduce waste during the industrial processing of raw materials.

Medicine sets the task not to cure, but to prevent diseases by recommending food rations, which would include vegetables, fruits and berries rich in medicinal properties.

Special studies have long established that therapeutic effect natural biologically active substances of fruits and vegetables is much higher than that of finished medicines. So, garlic contains essential oils that can kill influenza viruses, and is used by the population as a prophylactic against the disease. Vitamin C is absorbed better in the presence of P-vitamin substances, which are concentrated mainly in fruits and vegetables.

Let's analyze the chemical composition of vegetables in more detail.

Water makes up on average about 85-87% of the mass of vegetables. The normal water content ensures the juiciness of vegetables, the evaporation of moisture leads to their withering, deterioration in appearance and texture. Water in vegetables is mainly in a free state in the form of cell sap, in which valuable nutrients are dissolved; only 5% of water is associated with proteins and other substances.

Water is a medium in which various hydrolytic processes intensively proceed, which play an important role in the vital activity of vegetables and the preservation of their commercial quality. At the same time, it should be noted that an increased water content reduces their energy value (calorie content) and the percentage of yield. finished product when processing vegetables.

Water is a favorable soil for the development of microorganisms. Early varieties of vegetables that differ high content water in comparison with late varieties, are more easily exposed to microbiological and physiological diseases and to long-term storage not suitable.

Carbohydrates make up about 80% of the total dry matter found in vegetables. There is a lot of starch in potatoes (an average of 18%), in other vegetables (with the exception of legumes) easily digestible sugars predominate: sucrose, glucose and fructose. Their content can vary considerably: from 1.5-2.5% in potatoes, cucumbers, lettuce and spinach to 6-9.5% in carrots, beets, watermelons and melons.

Along with fiber, the skin of vegetables contains semi-fiber or gemmicellulose, which is a combination of cellulose with sugars. During the hydrolysis of semi-cellulose, free sugars are formed, which can be involved in respiration processes as a plant reserve material. However, the more gemicellulose, the coarser the texture, the lower the digestibility, but the better the shelf life, since, along with fiber, these substances provide the mechanical strength of vegetables. The content of semi-fiber is in the same range as fiber, from 0.5 to 2%.

Glycosides. These are complex compounds of sugars (glucose, rhamnose, galactose, etc.) with various non-carbohydrate substances: acids, alcohols, nitrogenous, sulfurous and other compounds.

Glycosides give vegetables a specific taste, sometimes astringent, sour or bitter. The glycoside solanine can accumulate in green potatoes during the germination of tubers, root crops and other vegetables. The content of solanine in green potatoes up to 0.02% causes severe poisoning, so the presence of green tubers in a batch of potatoes is strictly regulated (no more than 2%). Tubers with more than one quarter of their surface green are discarded.

Glycosides in the life of vegetables play the role of reserve substances, the sugars formed during their hydrolysis are involved in the processes of respiration. Many glycosides have antimicrobial, that is, bactericidal action, inhibiting the development of bacteria and fungi. The bitterness of many vegetables, due to the content of glycosides, is considered as a protective agent of the plant from being eaten by birds and other animals. So, burning taste pepper is created by the glycoside capsaicin, and horseradish and mustard - by sinigrin.

pectin substances. By their chemical nature, pectin substances are close to carbohydrates and are macromolecular compounds. They are included in the middle plates and cell walls, and in a dissolved state - in the cell juice of vegetables. This group of compounds includes protopectin, pectin, pectic and pectic acids.

Protopectin is composed of pectin and cellulose. According to some researchers, it contains araban gemmicellulose, which contains the sugar arabinose. Protopectin is insoluble in water and is responsible for the toughness of unripe vegetables. When ripe, protopectin splits with the release of free pectin, easily soluble in water, while the consistency changes from hard to soft, characteristic of mature vegetables; these changes, for example, are easily traced when tomatoes ripen.

Pectin is a polygalacturonic acid, the carboxyl groups of which are saturated with residues methyl alcohol. Hydrolysis of pectin usually occurs at the stage of overripeness and aging of vegetables as a result of the detachment of methoxyl groups and the breaking of the polygalacturonic chain of the molecule. In this case, pectic acid is first formed, then pectic acid. The cellular structure of vegetables is destroyed, they acquire a flabby texture and are quickly affected by diseases.

Modern ideas about the role of pectin substances have undergone significant changes. Studies have shown that they are very important for maintaining the normal physiological state of vegetables. The destruction of the structure of protopectin and pectin is directly dependent on the quality and keeping quality of vegetables.

For the human body, from ballast (indigestible substances), as previously thought, they have turned into substances that play the role of antitoxicants and antiradiants. Pectin substances, binding salts of heavy metals (lead, nickel, etc.), detoxify the body. Particularly important is their role as protective anti-radiants that remove radioactive isotopes of strontium, radium, etc. from the body.

Under current conditions, the presence of radiation-protective anti-radiants in food, which are the pectin substances of vegetables, is especially important.

organic acids. They are of great taste value, increasing the digestibility of both the vegetables themselves and the rest of the food when they are used together. They play a protective role against microbiological diseases of the vegetables themselves. Organic acids, as more oxidized substances, are easily involved in respiration processes and, along with sugars, are the most important substrate of the plant cell. That is why the sour taste of vegetables decreases during storage: this is especially noticeable in fruits and berries.

Many organic acids are volatile, create the aroma of vegetables, and have phytoncidal, that is, antimicrobial properties. In vegetables, malic acid and oxalic acid (in sorrel) predominate. The total acid content in vegetables ranges from 0.1-2%.

Intensity sour taste depends on the concentration of free hydrogen ions, denoted by the pH sign. In a neutral environment, the pH is 7, in an acidic environment it is below 7, in an alkaline environment it is above. In vegetables, the pH is less than 7, that is, an acidic environment prevails.

The sour taste can be neutralized by sugars, and enhanced by the presence of tannins (astringents). The pH value for many canned foods is regulated, since hyperacidity indicates signs of deterioration of the product.

Tannins. They are a variety of phenolic compounds that give vegetables a tart, astringent taste; they are found mainly in unripe vegetables. As vegetables ripen, the content of tannins decreases. These plant compounds are called tannins because of their ability to tan leather.

Phenolic compounds play an important role in the processes of respiration and immunity of potatoes and vegetables against microbiological diseases, and have antimicrobial properties.

Studies have established a direct relationship between the accumulation of phenolic compounds and the resistance of individual varieties of potatoes and vegetables against microbiological diseases.

For the human body, some phenolic compounds are very important due to their P-vitamin activity (catechins, tannins, etc.).

Under the action of atmospheric oxygen, phenolic compounds are easily oxidized with the formation of dark-colored substances - flobafen.

These processes are undesirable, especially when drying and preserving vegetables, since the appearance finished products getting worse. To prevent darkening of cut vegetables during processing, they are blanched, that is, treated with steam or boiling water. At the same time, oxidative enzymes are destroyed, in addition to the natural color, vitamins are better preserved in vegetables. The total content of phenolic compounds varies considerably - from hundredths to 1-2%.

Dyestuffs. The diverse color of vegetables is mainly created by four groups of organic compounds: chlorophyll, carotenoids, anthocyanins and flavonoids.

Chlorophyll - a green pigment involved in plant photosynthesis, is an ester of chlorophyllinic acid with two alcohols - phytol and menthol. At the center of the complex chlorophyll molecule is a magnesium atom. When magnesium is removed, which occurs during cooking of vegetables, pheophytin is formed, which gives the cooked vegetables first a yellow-brown, then a dark brown color. This color change is especially noticeable when cooking green vegetables for a long time.

As vegetables ripen, the amount of chlorophyll in them decreases, and carotenoids increase.

Carotenoids give vegetables their yellow to orange-red color. The main representative of this group of pigments is carotene, the properties of which are discussed in the "Vitamins" section. The more double bonds in the hydrocarbon chain of carotenoids (7-13), the brighter colored vegetables are.

Anthocyanins belong to the class of glycosides, they consist of a sugar residue and anthocyanidin pigment, a phenolic substance. The color of vegetables, depending on the type of pigment and the pH of the medium, can be red, blue, purple, with a variety of intermediate shades. Many anthocyanins have P-vitamin activity and antimicrobial properties.

Flavones (yellow-orange pigments) combine a large group of phenolic compounds, but flavonols mainly give color to vegetables. By their chemical nature and properties, flavonols are in many ways similar to anthocyanins.

Leukoanthocyanins are colorless precursors of anthocyanins and flavonols. By structure and properties, they are close to tannins and can be formed by their enzymatic oxidation. During hydrolysis with hydrochloric acid and the ripening of vegetables, leukoanthocyanins pass from a colorless form to a colored one - anthocyanins.

aromatic substances. The smell of vegetables is created by a large and varied chemical composition of various substances (terpenes, aldehydes, ketones, alcohols, organic acids, esters, and others). Contains many aromatics spicy vegetables- parsley, parsnip, celery, onion, garlic and others. A common property of aromatic substances is their volatility. Distilled during distillation, they are also called essential oils. Many of them have a strong bactericidal effect and are considered phytoncides. So, one clove of garlic is enough to sterilize the oral cavity from the flu virus for a day. That is why the consumption of onions and garlic is the most important preventive measure against this type of disease.

nitrogenous substances. They are found in vegetables in small quantities - from 0.5 to 1-2%, with the exception of legumes (up to 5%), cauliflower (4.5%), garlic (6.5%), spinach (3.5% ). The proteins of these vegetables are very valuable in terms of amino acid composition. In addition to proteins, nitrogenous substances include free amino acids, acid amides, ammonia compounds, and others.

However, being in small amounts, proteins play an important role in the life of the vegetables themselves. Protein biosynthesis is the basis of immunity, that is, the resistance of vegetables against microbiological and physiological diseases. Knowing how to regulate protein biosynthesis, scientists direct the development of new economic and botanical varieties of vegetables with desired properties that determine high yields, frost and drought resistance, resistance to microbiological diseases, and increased nutritional value.

A particularly important role in the life of vegetables is played by peculiar proteins - enzymes that regulate all biochemical processes that have a significant impact on the quality and shelf life of potatoes and vegetables. The processes of respiration, changes in the chemical composition during the ripening and aging of vegetables proceed with the participation of diverse enzymes; their inactivation, that is, destruction, leads to drastic changes in the quality of vegetable products.

Fats. Vegetables are found in very small amounts. Their total content in the pulp of vegetables is not more than 1%, in melons and gourds - pumpkin, watermelon, melon - fat is concentrated in the seeds.

vitamins. All vitamins are usually divided into two groups according to their solubility - water-soluble and fat-soluble. The first group includes vitamins B 1 B 2 , B 3 , B 6 , B 9 (folic acid), B 12 , B 15 , PP, C (ascorbic acid); to the second - A, D, E, K. In addition, a number of substances make up a group of vitamin-like compounds.

Vegetables are especially rich in such water-soluble vitamins as ascorbic acid, as well as in a slightly smaller amount - vitamins P and B 9,% cabbage - vitamin U. Vitamins of the B group (with the exception of B 9), as a rule, are found in vegetables in tenths and hundredths fractions of a milligram and do not play a significant role in the vitamin balance of nutrition.

Of the fat-soluble vitamins, vegetables contain mainly carotene (provitamin A).

Vitamin C was discovered by the Hungarian biochemist Szent-Györgyi, who called it ascorbic acid, that is, it acts against the disease with scarbut or scurvy.

A characteristic sign of the appearance of scurvy is the general weakness of the whole organism with a significant decrease in appetite and performance, while the gums of the teeth begin to bleed, pinpoint hemorrhages appear especially noticeably under the skin of the legs, the activity of the heart, liver, and kidneys worsens. Numerous studies have established that vitamin C has a neutralizing effect on various drugs and toxic substances, suppressing their toxicity, and accelerates the healing of wounds and bone fractures.

Ascorbic acid is partially destroyed by the action of metal equipment during industrial processing, metal utensils, culinary preparation food. Therefore, the contact of vegetable products with metal should be minimized. The destruction of vitamins is accelerated by prolonged exposure to high temperatures. But ascorbic acid is well preserved in an acidic environment, therefore, for example, sauerkraut is an excellent source of this vitamin for a long period.

Preservation of vitamin C in the product is facilitated by the content of sugars, proteins, amino acids, sulfur compounds, which inhibit the activity of the enzyme ascorbine oxidase, which destroys ascorbic acid.

A lot of vitamin C is found in sweet red pepper - 250 mg per 100 g of edible part, green pepper - 150, parsley-greens - 150, dill - 100, spinach - 55, sorrel - 43, white cabbage and kohlrabi - 50, cauliflower - 70, green onion (feather) - 30. The presence of vitamin C in potatoes is relatively small - from 7 to 20 mg%. However, when consuming 300 g of tubers per day, even taking into account the destruction of ascorbic acid during cooking for 1/4 of the original content, we get 30-40% of the required amount of vitamin from potatoes.

Vitamin P. Like ascorbic acid, vitamin P was first discovered by the scientist Szent-Gyorgyi, who in 1936 isolated a crystalline powder from the peel of a lemon and called it citrine. Under vitamin P, an extensive group of substances of a polyphenolic nature, called bioflavonoids, is combined. Medicinal properties bioflavonoids lie in their ability to normalize the permeability and elasticity of blood capillaries. It is assumed that vitamin P protects the hormone adrenaline from oxidation, on which the integrity of blood capillaries depends. Currently, more than 150 polyphenols with P-vitamin activity are known. Promoting the expansion of blood vessels, P-vitamin substances also have an anti-inflammatory and anti-allergic effect on the human body. All these substances not only prevent sclerosis of blood vessels, but also reduce blood pressure, preventing hemorrhage in the heart muscle and cerebral cortex.

Vitamin P contributes to an increased therapeutic effect of ascorbic acid, which is why it is also called vitamin C 2. Their combined use in the prevention and treatment of many infectious, peptic and other diseases is more effective than each separately.

Vitamin B 9 is more commonly referred to in the literature as folic acid. With a lack of it in the blood, the amount of hemoglobin sharply decreases and anemia or leukemia appears. A decrease in the percentage of hemoglobin in the blood also slows down its clotting, which leads to internal hemorrhages. It has been established that folic acid promotes better absorption of vitamin B 12 in the gastrointestinal tract.

These vitamins, acting together, ensure the processes of normal blood circulation. Synergy, that is, the combined therapeutic effect of folic acid and vitamin P, is recommended in the prevention and treatment of radiation sickness, atherosclerosis, liver diseases and obesity.

Lots of folic acid in leafy vegetables. During the heat treatment of vegetables, it is easily destroyed, so greens, as a source of vitamins, are best consumed raw, especially green salads.

Vitamin U. Isolated from white cabbage juice; is an important source of methyl groups used by the body in metabolic processes. It has a therapeutic effect in gastritis and other gastrointestinal diseases.

Along with white cabbage vitamin U is found in a lot of vegetable greens: parsley, dill, onion (feather), spinach, lettuce; it is also found in other vegetables - potatoes, tomatoes, cucumbers.

Vitamin A - growth vitamin, especially necessary for children; it is also called axerophthol, which helps prevent xerophthalmia eye disease. In low light, vision weakens up to its complete loss at dusk, in the common people's "night blindness". The cornea of ​​​​the eyes undergoes drying (xerosis - in Latin "drying"), while the protective functions of the lacrimal glands are violated and the eyes are easily affected by pathogens. With a lack of vitamin A, inflammation of the mucous membrane of the respiratory organs also occurs, and the risk of pneumonia, tuberculosis, and measles increases. It has been experimentally established that vitamin A affects the redox processes of respiration, protein and carbohydrate metabolism, and the functions of the endocrine glands.

However, it should be noted that excessive consumption of vitamin A is not desirable, as this can lead to poisoning of the body - hypervitaminosis.

Unlike animal products - meat, milk, containing directly vitamin A, vegetables contain its provitamin - carotene. Carotene is the pigment that gives vegetables their yellow-orange color.

The richest in carotene (in mg per 100 g of edible part): carrots - 9; spinach - 4.5; sorrel - 2.5; lettuce - 2.75; green onion (feather) - 2; sweet red pepper - 2; sweet green pepper - 1; parsley - 1.7; pumpkin - 1.5.

Vitamin K (naphthoquinone) contributes to normal blood clotting (K - from the word "coagulation" or clotting).

A lack of this vitamin can lead to decreased blood clotting and internal bleeding.

In addition, vitamin K has a positive effect in the treatment of diseases of the liver and intestinal tract.

Vitamin K is found in a lot of salad-spinach vegetables and other greens, as well as in potatoes, white cabbage.

trace elements. Minerals in vegetables are contained in the range from 0.5 to 1.5%. Depending on the quantitative content in food, they are divided into two groups - macro- and microelements. Macronutrients include potassium, sodium, phosphorus, sulfur, magnesium contained in vegetables in tenths and hundredths of a percent. A person receives these elements in sufficient quantities also from cereals and other cereals and food of animal origin, therefore he does not experience their deficiency in nutrition. Microelements are contained in vegetables in thousandths and millionths of a percent, but for the human body, each of them is of paramount importance.

Academician V. I. Vernadsky's research on the close relationship between the chemical composition of the organic world and the mineral substances of the environment served as the basis for a comprehensive study of the biological role of microelements. Back in 1916, the scientist noted that the life of every living organism is closely connected with its structure of the earth's crust.

In total, about 70 chemical elements have been identified in the human body, of which 14 microelements are currently considered essential. These are iron, iodine, copper, zinc, manganese, molybdenum, selenium, chromium, nickel, tin, silicon, fluorine, vanadium, cobalt. Some of them were found in negligible quantities, in the form of traces.

Vegetables, extracting trace elements from the deep layers of the soil through the root system, accumulate them in all parts of the plant, being the most important source of these substances in nutrition.

Numerous studies by Soviet scientists have established that iron, cobalt, nickel, copper, manganese and other microelements are most active in the process of blood circulation.

About 200 enzymes (1/4 of known species) are activated by metals.

Iron is the most common trace element (it contains 4-5 g in the human body), regulates the processes of blood circulation, growth, respiration, fat and mineral metabolism, being part of a number of enzymes. Relatively a lot of iron in spinach, sorrel, parsley, dill, garlic, tomato, carrots, beets, cauliflower.

Cobalt (the body of an adult contains 1.5 g) is part of vitamin B 12, which promotes the synthesis of hemoglobin. Cobalt is found in the liver and kidneys, plays an important role in the processes of growth, carbohydrate and fat metabolism. The presence of cobalt contributes to the accumulation of many vitamins in vegetables.

Nickel is involved in complex biochemical processes occurring in the body, and the fluctuation of its content in the blood is their reflection. For example, a decrease in the concentration of nickel in the blood was noted in patients with cardiosclerosis, cirrhosis of the liver, etc. This is a very toxic element (it causes damage to the lung tissue).

From vegetables, a noticeable amount of nickel was found in potatoes, white cabbage, carrots, watermelon, garlic, green onions, lettuce, spinach, dill.

Copper (in the human body it is about 100 mg) is part of many enzymes that regulate the redox processes of respiration, a hematopoietic element, which has a particularly effective effect together with iron. It was found that many diseases in children are associated with a deficiency of copper in the body; in an adult, the deficiency of this element is almost not manifested. A dose of copper consumption above the norm (more than 2 mg per day) is very toxic.

When canning in vegetables, the amount of copper may increase during the contact of the product with the equipment, so its content is strictly limited (no more than 5-30 mg per 1 kg of product).

Copper is rich in tomatoes, eggplant, spinach, green peas, rutabaga, which are recommended in the diet for pernicious anemia.

Zinc (an adult contains about 2.5 g). The biological role is not fully understood, although it is a vital trace element. Its role is twofold. On the one hand, life is impossible without it, since it is a part of hematopoietic and other metal enzymes, on the other hand, zinc compounds are very toxic (1 g of zinc sulfate causes severe poisoning, so the content of this metal in canned food is strictly regulated).

Manganese in the body of an adult is found to be about 12 mg. It accelerates the formation of chlorophyll in green plants, is part of redox enzymes. The lack of manganese in food causes a decrease in growth, vitality. Contained in all green vegetables, cabbage, potato tubers.

Iodine (in the human body contains 10 mg) is distributed in very small doses in soil, river and, especially, sea water.

Disease thyroid gland(development of goiter) is associated with a lack of iodine in food, It is involved in the absorption of calcium and phosphorus by the body.

A rich source of iodine is seaweed, as well as beets.

Fluorine (in the body of an adult 2.6 g). Increases the strength of the skeleton and tooth enamel. A lack of fluoride causes caries, and an excess causes an acute disease of fluorosis (spotted tooth enamel).

Phytoncides. The name "phytoncides" consists of two parts: "phyto" - a plant, a particle of the word "cides" means that they are poisonous. - But these are healing poisons of plants, - this is how the founder of the doctrine of phytoncides, Professor of Leningrad University B.P. Tokin, said about them. The fact is that phytoncides have a toxic effect on microorganisms that infect plants, and on microflora that is pathogenic for the human body.

Very convincing experiments can be carried out on the phytoncidal effect fresh onion or garlic: the onion is rubbed and the resulting slurry is placed next to a drop of liquid in which there are any mobile pathogenic microbes. Within a minute, it is found that the movement of bacteria stops. If, after 10 minutes, these bacteria are sown on a nutrient medium, they will not multiply: they were killed by volatile substances released from onions.

Phytoncides are not one, but a wide variety of substances that can have a detrimental effect on microorganisms in subtle doses. But non-volatile substances also have phytoncidal properties, for example, coloring pigments - anthocyanins, flavones, organic acids and other compounds.

Eating raw vegetables rich in phytoncides prevents gastrointestinal diseases.

Phytoncides of vegetable food exert their sterilizing effect in the upper sections respiratory tract, preventing the development of tonsillitis, bronchitis, etc.

Although the chemical composition of onion phytoncides and. of garlic is not yet known exactly, but the substance alliin, in particular, has been isolated from garlic bulbs, which, at a dilution of 1: 250,000, has an overwhelming effect on the development of pathogenic bacteria and is used as a therapeutic drug. But alliin is only one of the components of a complex complex of garlic substances that are phytoncides.

Phytoncidal properties of plants are widely used in agriculture and the practice of storing vegetable products. Both favorable and negative facts of the interaction of vegetables with each other are revealed. For example, planting tomatoes between the rows of gooseberry bushes prevents the latter from being damaged by agricultural pests. Water infusions of onion or garlic scales instantly kill the spores of the phytophthora fungus that affects potato tubers. Spraying with such an extract of sand, which is used during storage for interlayering carrots, restrains damage to root crops by a fungus (white rot). The same antimicrobial effect is exerted by radish and horseradish, being in the neighborhood.

In addition to onions, spicy vegetables - dill, parsley, parsnip, celery and others rich in essential oils have a high phytoncidal effect.

The chemical composition of fresh fruits and berries depends on their type, degree of maturity, harvesting time, storage methods, etc.

Fresh fruits and berries have a high water content - 72 - 96%. It causes physiological processes in fruits and berries, and also contributes to the development of various microbiological processes that lead to their deterioration. During storage of fruits, water can evaporate, which leads to a decrease in keeping quality and a decrease in their shelf life.

The main energy material of fruits and berries are carbohydrates- sugars, starch, cellulose (fiber), pectin substances, hemicellulose. The calorie content of carbohydrates is low, but the presence of sugars in fruits and berries due to their easy digestibility makes them especially useful for humans.

Of the sugars in fruits and berries, glucose, fructose and sucrose are most often and in the greatest quantity. The total amount of sugars depends on many factors: crops, varieties, growing areas, agricultural practices, soil and weather conditions, etc. The ratio of various sugars mainly depends on the type of fruit and berries. For example, apples and pears contain 6-12% fructose, 1-5% glucose and 0.5-5.5% sucrose; in apricots - respectively 0.1 - 3.2, 0.1 - 3.2 and 4.5 - 10%, and in cherries - 3.3 - 4.4, 3.8 - 5.3 and 0 - 0 ,8 %. The starch content in fruits and berries reaches 1%. Most starch is found in unripe apples. As the fruit ripens, it hydrolyzes to form sugars and other substances.

Cell membranes of fruits and berries are built mainly from cellulose (fiber), which is a polysaccharide. Its content in fruits and berries is about 1 - 2%. Fiber is almost not absorbed by the human body, but contributes to the normal functioning of the intestines.

pectinsubstances- These are high-molecular compounds of a carbohydrate nature. In fruits and berries, they are found in the form of pectin, protopectin and pectin acid. Their content in apples is 0.8 - 1.3%, in plums - 0.5 - 1.3, in raspberries - 0.1 - 0.7%. Protopectin is contained in intercellular spaces and in cell membranes, does not dissolve in water and determines the hardness of fruits. As it matures, protopectin breaks down to form pectin and hemicellulose. Such a process occurs during the cooking of fruits, since at a temperature of 80 - 85 ° C, protopectin is hydrolyzed. This property is used when blanching fruits to remove the skin from them.

Common organicacids, contained in the fruits are apple, lemon and wine. Less often and in a small amount fruits contain benzoic, salicylic, succinic acids, etc. The total acidity of fruits and berries ranges from 0.4 to 8%.

Certain types and varieties of fruits can simultaneously contain one, two or more acids. In stone fruits and pome fruits, for example, malic and citric acids are found. Malic acid is especially abundant (up to 6%) in dogwood and barberry. Lemon acid found mainly in lemons (up to 7%), cranberries and pomegranates. Tartaric acid predominates in grapes (0.3 - 1.7%). Benzoic acid is found in a small amount (0.1%) in lingonberries and cranberries, salicylic acid in raspberries and strawberries. Due to the fact that benzoic acid has antiseptic properties, cranberries and lingonberries are well preserved. There are few acids in cherries, pears, apricots.

The taste sensation of acids in fruits is significantly affected by Sahara, tanninssubstances. The sugar contained in the pulp of the fruit, as it were, masks the sensation of sour taste, and tannins, on the contrary, emphasize it. So, dogwood fruits contain 9% sugar, but they seem very sour and tart, as they contain a relatively large amount of malic acid and tannins.

The role of acids in canning or culinary processing of fruits is significant. Thus, the amount of acids in the raw material affects the sterilization mode: the higher the acidity of the raw material, the faster the microorganisms die in it when the canned food is heated.