Carbohydrates

The carbohydrate content of most vegetables does not exceed 5%, but in some of them, for example, in potatoes, the amount of carbohydrates reaches 20%, in green peas -13%. Carbohydrates in vegetables are mainly represented by starch and, to a lesser extent, sugars, with the exception of beets and carrots, in which sugars predominate. Fruits contain more carbohydrates than vegetables, and their content averages 10%.

Sahara

Fruits contain the most abundant sugars (glucose, fructose and sucrose).

A peculiarity of fruit and vegetable sugars is the wide representation of fructose among them.

Products	Sugar content in %
	glucose	fructose	sucrose
Apples	2,5-5,5	6,5-11,8	1,5-5,3
Pears	0,9-3,7	6,0-9,7	0,4-2,6
Quince	1,9-2,4	5,6-6,0	0,4-1,6
Apricots	0,1-3,4	0,1-3,0	2,8-10,4
Peaches	4,2-6,9	3,9-4,4	5,0-7,1
Plums	1,5-4,1	0,9-2,7	4,0-9,3
Cherries	5,3-7,7	3,4-6,1	0,4-0,7
Cherry	3,8-5,3	3,3-4,4	0,2-0,8
Red currants	1,1-1,3	1,6-2,8	0
Black currant	3,3-3,9	4,0-4,8	0,2-0,4
Gooseberry	1,2-3,6	2,1-3,8	0,1-0,6
Raspberries	2,3-3,3	2,5-3,4	0-0,2
Grape	7,2	7,2	0
Bananas	4,7	8,6	13,7
Pineapples	1,0	0,6	8,6
Persimmon	6,6	9,2	0

In vegetables, sugar is also presented in three types (glucose, fructose and sucrose). The greatest amount of sugars is found in:

• carrots (6.5%)
• beets (8%)
• watermelons (7.5%)
• melons (8.5%)

Other vegetables contain little sugar. Sucrose predominates in carrots, beets and melons; Watermelons are an exceptional source of fructose.

Cellulose

Fiber is widely represented in vegetables and fruits, reaching 1-2% of their composition. Berries are especially high in fiber (3-5%).

Fiber, as you know, is a substance that is difficult for the digestive system to digest. Vegetables and fruits are a source of predominantly soft fiber (potatoes, cabbage, apples, peaches), which breaks down and is quite fully absorbed.

In the light of modern scientific ideas, fiber from vegetables and fruits is considered as a substance that promotes the removal of cholesterol from the body, and also has a normalizing effect on the vital activity of beneficial intestinal microflora.

Chemical composition of fresh fruits and vegetables. The nutritional value of fresh fruits and vegetables is determined by the presence of carbohydrates, organic acids, tannins, nitrogenous and mineral substances, as well as vitamins. Fruits and vegetables improve appetite and increase the digestibility of other foods. Some fruits and vegetables have medicinal value (raspberries, black currants, grapes, blueberries, strawberries, pomegranates, carrots, etc.), as they contain tannins, coloring and pectin substances, vitamins, phytoncides and other compounds that perform a certain physiological role in the body person. Many fruits contain antibiotics and radiation-protective substances (antiradiants), which are capable of binding and removing radioactive elements from the body. The content of individual substances in fruits and vegetables depends on their variety, degree of maturity, growing conditions and other factors.

Water. Fresh fruits contain 72-90% water, nuts - 6-15, fresh vegetables - 65-95%. Due to the high water content, fresh fruits and vegetables are unstable in storage, and the loss of water leads to a decrease in quality and loss of presentation (withering). A lot of water is contained in cucumbers, tomatoes, lettuce, cabbage, etc., so many vegetables and fruits are perishable foods.

Minerals. The mineral content in fruits and vegetables ranges from 0.2 to 2%. Of the macroelements in fruits and vegetables, there are: sodium, potassium, calcium, magnesium, phosphorus, silicon, iron; micro- and ultra-microelements contain: lead, strontium, barium, gallium, molybdenum, titanium, nickel, copper, zinc, chromium, cobalt, iodine, silver, arsenic.

Carbohydrates. Fruits and vegetables contain sugars (glucose, fructose, sucrose), starch, fiber, etc. The percentage of sugars in fruits ranges from 2 to 23%, in vegetables - from 0.1 to 16.0%. Starch accumulates in fruits and vegetables during their growth period (potatoes, green peas, sweet corn). As vegetables (potatoes, peas, beans) ripen, the mass fraction of starch in them increases, and in fruits (apples, pears, plums) it decreases.

Fiber in fruits and vegetables - 0.3-4%. It makes up the bulk of their cell walls. When some vegetables (cucumbers, radishes, peas) become overripe, the amount of fiber increases and their nutritional value and digestibility decrease.

Organic acids. Fruits contain from 0.2 to 7.0% acids, vegetables - from 0.1 to 1.5%. The most common fruit acids are malic, citric, and tartaric. Oxalic, benzoic, salicylic and formic acids are found in smaller quantities.

Tannins give the fruit an astringent taste. There are especially many of them in quince, persimmon, rowan, pears, and apples. Oxidized under the action of enzymes, these substances cause darkening of fruits when cut and pressed, and a decrease in their quality.

Coloring substances (pigments) give fruits and vegetables a certain color. Anthocyanins give fruits and vegetables a variety of colors from red to dark blue. They accumulate in fruits during their full ripeness, so the color of the fruit is one of the indicators of its degree. Carotenoids color fruits and vegetables orange-red or yellow. Carotenoids include carotene, lycopene, and xanthophyll. Chlorophyll gives fruits and leaves their green color. When fruits (lemons, tangerines, bananas, peppers, tomatoes, etc.) ripen, chlorophyll is destroyed and, due to the formation of other coloring substances, the color characteristic of ripe fruits appears.

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

Glycosides (glucosides) give vegetables and fruits a sharp, bitter taste and specific aroma, some of them are poisonous. Glycosides include solanine (in potatoes, eggplants, unripe tomatoes), amygdalin (in the seeds of bitter almonds, stone fruits, apples), capsaicin (in peppers), sinegrin (in horseradish), etc.

Vitamins. Fruits and vegetables are the main sources of vitamin C (ascorbic acid) for the human body. In addition, they contain carotene (provitamin A), B vitamins, PP (nicotinic acid), vitamin P, etc.

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

Fats. Most fruits and vegetables contain very little fat (0.1-0.5%). There are a lot of them in nut kernels (45-65%), in the pulp of olives (40-55%), and also in apricot kernels (20-50%).

Phytoncides have bactericidal properties and have a detrimental effect on microflora, releasing toxic volatile substances. The most active phytoncides are onion, garlic, and horseradish.

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Tubers

Potatoes are of great importance in human nutrition and are rightfully considered the second bread, and in Siberia they are jokingly called the “Siberian fruit”. It is widely used for food in a variety of forms - over 100 different dishes can be prepared from it. It serves as a raw material for the production of various products - chips, potato grits, flakes, purees, frozen semi-finished products, as well as for the production of starch and alcohol. Potatoes are also important as a fodder crop.

Tuber structure. In a potato tuber, a top and a base are distinguished, i.e. place of attachment to the underground stem. Young tubers are covered with a thin layer of epidermis. During the process of maturation, cells are formed in the epidermis in which cork substance accumulates, they become coarser and turn into a dense skin - periderm. The thickness and density of the skin, its integrity, and the condition of the cork layer affect the quality and suitability of potatoes for storage.

Eyes and lentils are located on the surface of the skin. The eyes consist of a group of buds and are located at different depths in the thickness of the skin. Lentils are numerous small holes and serve as an apparatus for air exchange.

The core (pulp) of the tuber is divided into the outer, rich in starch, and the inner, more watery, which contains less starch.

Chemical compositionaw Potato tuber production depends on the variety, growing conditions, maturity of the tubers, terms and conditions of storage, etc.

On average, potatoes contain (in%): water – 75.0; starch 18.2; proteins – 2.0; sugars – 1.5; fiber – 1.0; fat – 0.1; minerals – 1.1; pectin substances – 0.6.

A significant proportion of potato dry matter is carbohydrates, where a large proportion is starch (in most table varieties its amount is 15–18%).

Starch is distributed unevenly in the tuber: more in the outer layers and less in the center. Potatoes with different starch contents have different technological properties, which determines their culinary use. Tubers with crumbly white or cream-colored pulp (i.e. containing a large amount of starch) are advisable to use for making purees, potato products, and puree soups. Tubers with dense or watery pulp - for soups, boiled and fried potatoes.

Most of the nitrogenous substances in potatoes are protein - tuberin, which is complete.

The amount of vitamin C in potatoes is on average 10 - 18 mg%, after 4 - 5 months of storage - 15 mg%, and there is more of it in the bark than in the core. As we see, there is a relatively small amount of vitamin C in potatoes, however, given the place of potatoes in our diet, we can say that for most of the year we satisfy the body’s need for ascorbic acid precisely due to this vegetable. Potatoes contain other vitamins: B 1, B 2, B 6, B 3, PP.

There are very few organic acids in potatoes. These acids include malic, citric, oxalic, as well as chlorogenic, caffeic, and quinic. The latter predominate in tubers when they are damaged or affected by diseases.

Economic and botanical varieties of potatoes. According to the ripening period, potato varieties are distinguished: early (their ripening period is up to 80 days), mid-early (80 - 90 days), mid-ripening (from 90 to 100 days), mid-late (up to 120 days), and late-ripening (from 120 to 140 days or more ).

According to their purpose, potato varieties are divided into table, technical, fodder and universal.

For table varieties characterized by rapid cooking, good taste, shallow-set eyes, preservation of the natural color of the pulp when cutting and after cooking. To facilitate the process of cleaning tubers on potato peeling machines and reduce waste, the best varieties of potatoes are those that have a round or round-flat shape and are of medium size.

The taste of potatoes and their culinary merits are influenced by various factors: chemical composition (as we have already said, the amount of starch), the size of starch grains, the structure of the skin and pulp, etc.

Technical varieties used to produce starch and alcohol. They are characterized by high starch content, and for the production of starch, varieties with larger starch grains are preferable.

Feed varieties must have a high dry matter content.

Universal varieties have characteristics that allow them to be used as table food and for technical processing.

Depending on the starch content, potato varieties are distinguished with low starch content (12 - 15%), medium (16 - 20%) and high (more than 20%); according to the size of starch grains - coarse-grained and fine-grained.

The most important regionalized economic and botanical potato varieties suitable for long-term storage are: Agronomichesky, Berlichingen, Veselovsky, Lorch, Lyubimets, etc.

The size of tubers is determined by their largest diameter, and the shape is determined by the ratio of the width (largest transverse diameter) to length (largest diameter) - the shape index. For elongated tubers this ratio is 1:1.5 or more. Tubers with a smaller width-to-length ratio are considered round-oval. Based on this characteristic, the following forms of tubers are also distinguished: onion, round, oval, elongated oval, long, etc.

The main types of color of tubers: white - with various manifestations of yellowness (Lorch, Ogonyok); red - with shades from light pink to intense red (Woltmann, Berlichingen); violet-blue - from bright blue to light blue (Late blight-resistant, Cast iron).

Tubers also differ in the external characteristics of the skin (smooth, flaky, mesh), in the number of eyes and the depth of their occurrence (few, many, deep, superficial).

Tubers differ according to the color of the pulp (white, white with pink spots, white-yellow, yellow, pink, blue-violet).

Quality requirements. Fresh food potatoes.

The quality of potatoes is determined by appearance, size, and the presence of tubers with acceptable deviations. The presence of soil stuck to the tubers should be no more than 1%.

Tubers must be whole, dry, not sprouted, uncontaminated, and free of diseases.

It is not allowed in a batch of potatoes to contain tubers with greening of more than ¼ of the surface, wilted, with slight wrinkles in the batch of potatoes of the current year, crushed, damaged by rodents, wet, dry, ring and button rot, late blight (up to 2% is allowed in areas where this disease is widespread) , frozen, steamed and with signs of “suffocation”, as well as tubers with foreign odors caused by the use of wastewater and pesticides for irrigation. Such potatoes are used for feed purposes and as waste.

Potatoes that do not meet the requirements of the standard, but are suitable for sale and processing in excess of permissible quantities, are considered non-standard.

Potatoes that are unsuitable for sale and processing are classified as waste (crushed tubers, less than 20 mm in size, frozen, damaged by rodents, affected by diseases).

In a number of foreign countries, according to standards, potatoes are divided by quality into several commercial varieties: in the USA - into four varieties (select, No. 1, commercial, No. 2), in Poland - into two varieties. The standards take into account the characteristics of botanical varieties, more clearly define the nature of mechanical damage, more strictly define the tolerance for damage, etc.

Jerusalem artichoke(earthen pear) are small tubers of a perennial plant, very undemanding to external conditions and growing in all regions of Russia except the northern ones. They are eaten fried, baked and boiled, and are also used to produce fructose and alcohol; they are also important as a fodder crop.

Sweet potato– sweet potatoes (common in South America, Japan, China, India). In appearance, composition and storage conditions it is close to potatoes. Contains up to 20% starch and 3 – 4% sugar.

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Roots

Types of root vegetables

Many types of root vegetables have been actively consumed by people throughout the history of human civilization. In addition, the beneficial properties of root vegetables are used in folk medicine. as well as in pharmaceutical and cosmetic production. As a rule, root vegetables are famous for their vitamin and mineral composition, as well as nutritional value.

The distinctive properties of root vegetables are due to the chemical composition of this part of the plant, in which the supply of elements necessary for growth, as well as vitamins and other compounds, is concentrated. Specialists in the modern food industry operate with the concept of table root vegetables. In turn, table root vegetables are understood as succulent underground components of agricultural crops that are grown for use for culinary purposes.

In addition to cooking, root vegetables are used as highly nutritious pet food containing significant amounts of vitamins. All types of root vegetables belong to plant families such as Apiaceae, for example carrots, parsnips or parsley, as well as Asteraceae, for example scorzonera and Brassicas, i.e. turnip, rutabaga or radish.

Composition of root vegetables

The chemical composition of root vegetables, as well as other basic biological and consumer characteristics of products, depend primarily on the species of the plant. However, it is worth especially emphasizing that all types of root vegetables can boast a unique and naturally balanced vitamin and mineral composition, which is enriched with a significant amount of compounds that are truly vital for both the plant and the human body.

The composition of root vegetables contains nutrients, as well as vitamins C, A, E, PP. In addition, root vegetables contain essential amino acids, minerals, natural sugar-containing and pectin compounds. Regular consumption of root vegetables can significantly improve a person's health.

Roots

Root vegetables include vegetables, the edible part of which is an overgrown fleshy root. Some species also use greens for food. Depending on the structure of the root, there are three types of root vegetables: carrot, beet and radish.

Carrot-type root vegetables are vegetables with an elongated root shape, which can be cylindrical, conical, elongated conical, spindle-shaped and blunt or sharp at the end. Root crops of this type have a clearly demarcated bark (phloem) and a core (xylem). Between them is the cork cambium. The top of the root crop is covered with natural periderm. In terms of composition and amount of nutrients, the bark is more valuable than the pith. Root vegetables of this type include carrots, parsley, celery, and parsnips.

Beet-type root vegetables are vegetables with round, round-flat, oval or elongated roots. Represented by table beet and sugar beet. Only table beets are used as a vegetable crop. The root vegetable has dark red flesh with rings of lighter toga, which is due to the alternation of xylem (light rings) and phloem (dark rings) tissues. The less specific gravity the xylem occupies, the higher the nutritional value of beets.

Radish-type root vegetables are vegetables with rounded, turnip-shaped, elongated-conical root vegetables. A feature of their internal structure is the radial arrangement of secondary xylem, phloem and parenchyma tissue. The cambium layer is located directly below the periderm. Root vegetables of this type include radishes, radishes, rutabaga and turnips.

Root vegetables of all types are characterized by common morphological characteristics: a head in the upper part with leaf petioles and buds at the base, a root body (the main edible part) and a root tip (the main one), and beet-type root vegetables have lateral roots. In other root vegetables, thin lateral roots are easily torn off during harvesting and, as a rule, are absent. The tips of the root are the most vulnerable part of the root crop, so during storage it easily gets stuck and is affected by microorganisms (white or root rot). Trimming the tip after harvest improves the shelf life of root crops. On top, the root vegetables are covered with a natural periderm (skin), which adheres to the pulp and protects it from adverse external influences.

The peculiarity of all root vegetables is their ability to heal mechanical damage by suberinization of cells, as well as their easy digestibility. The most easily withered root vegetables are carrots and radishes; the least susceptible are beets, radishes, turnips and rutabaga.

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Tomato vegetables

Tomato vegetables include tomatoes, sweet and hot peppers, and eggplants. They take about 20 % acreage of vegetables, are widely used in the canning industry, home cooking, and also in fresh form. Tomato processing products - tomato paste, sauce, puree - are an integral part of many types of canned vegetables and fish. Tomato juice is one of the most popular drinks. Sweet pepper is a valuable raw material that is included in many canned vegetables. Hot peppers are used for pickling and fermenting vegetables.

Tomato vegetables are heat-loving crops. They grow in the southern regions of Ukraine, in Moldova, the Lower Volga region, in the North Caucasus, in the Rostov region. The bulk of vegetables are produced by collective and state farms.

Tomatoes are grown mainly by seedlings. According to the ripening period, varieties are divided into early (growing season 110-115 days), mid-ripening (120-130 days) and late ripening (135-150 days). The fruit of tomatoes is a juicy multi-seeded berry. Consists of skin, pulp and seed chambers (from 2 to 6-8). The coloring of the skin and pulp is due to coloring substances. Lycopene predominates in fruits with red flesh, carotene and xanthophyll - in yellow-colored fruits. The shape of the fruit is a varietal characteristic. The fruits are flat-round, round, plum-shaped, and conical. The weight of the fruit varies from 20-60 g for small-fruited varieties to 100-300 g or more for large-fruited varieties.

Fruits have the following stages of maturity: green (not finished growing), milky white, brown, pink and red (ripe). Fruits of intermediate maturity - milky white, brown, pink - are capable of post-harvest ripening.

Chemical composition of tomatoes (in%): water - 93-94; dry matter - 6-7 (including sugars - 3-4); nitrogenous substances - about 1; fiber 0.6-0.7; organic acids - 0.5. Vitamin C content is 20-40 mg%. Dry hot weather contributes to the accumulation of sugars in fruits. In rainy, cool summer conditions, fruits contain less dry matter and sugars, but more organic acids.

The following varieties are zoned in commercial tomato production zones: early- White filling. Kievskiy 139, Konservny Kievskiy, Moldavskiy early, Talalikhin, Morning, Svitanok; mid-season- Volgogradsky, Donetsk, Custom 280, New Transnistria, Torch. Varieties suitable for machine harvesting include: Fakel, Novinku Pridnestrovie, Kubansky standard, Nistra, Novinku Kuban.

Wild fruits and berries have long been used in fresh and processed forms in human nutrition. As for representatives of the fauna, for many of them wild flora is the main and main food product. Many plants also have medicinal properties. The medicinal use of berries and fruits is mentioned in ancient medical books and herbalists of different nations.

Wild fruits and berries contain significant amounts of sugars, organic acids, vitamins, mineral salts and other nutritionally and medicinally valuable substances.

Berries and fruits, consumed together with other foods, improve the digestion of food and promote the absorption of proteins, fats and minerals.

Sugars in wild fruits and berries are represented mainly by glucose (grape sugar) and fructose (fruit sugar). There is very little sucrose (beet or cane sugar), and in some fruits (common blueberries, red currants, cloudberries, edible honeysuckle, etc.) it is completely absent. The amount of fructose and glucose in many fruits is approximately the same, although some of them (for example, rowan, lingonberry, wood sorrel apples, wood pears) have more fructose, which has a sweeter taste than glucose. The fruits of mountain ash and chokeberry contain the cyclic alcohol sorbitol. It has a sweet taste and can serve as a sugar substitute for diabetics.

Starch. Cellulose. Pectic substances

In addition to sugars, wild fruits and berries also contain carbohydrates of a more complex structure - starch, fiber and pectin.

Starch is usually found in unripe apples and pears. As they mature, it breaks down into simpler compounds - maltose and glucose.

The cell membranes of fruits and berries are built from fiber. It is almost not digested in the human gastrointestinal tract. The role of fiber is multifaceted and consists not only in mechanical irritation of the intestinal walls, which enhances the secretion of digestive juices, intestinal motility, consumption of foods containing fiber, normalizes the digestion process and prevents constipation.

Among carbohydrates, pectin substances occupy a special place. With the acids contained in the fruits and sugar, they are able to form jelly. Without pectins, it would be difficult to make jams, jellies, marshmallows, marmalade, etc.

Research conducted in recent years has shown that pectin substances have the ability to bind and neutralize compounds of certain radioactive and heavy metals, such as lead, cesium, cobalt, etc., that enter the human body. The beneficial effect of pectin substances in the treatment of diseases of the digestive system (enteritis, colitis, enterocolitis, etc.), as well as burns and ulcers, has also been proven.

Pectin substances have an anti-atherosclerotic effect.

Some wild fruits and berries are distinguished by a significant content of pectin substances (forest apples, black currants, rose hips, cranberries, strawberries, hawthorn, etc.).

Organic acids

Acids, together with sugars, pectin and tannins, determine the taste of fruits and berries. They stimulate appetite, increase the secretion of gastric juice and pancreatic juice, and stimulate intestinal motility.

Organic acids help dissolve uric acid salts (urates) and remove them from the human body.

Malic and citric acids predominate in wild fruits and berries. In berries (cranberries, blueberries, blueberries, lingonberries, currants, strawberries, cloudberries, etc.), citric acid occupies a leading place; Pome fruits (forest apples, pears, rowan, chokeberry), as well as raspberries, sea buckthorn, blackberries, and hawthorn contain more malic acid.

Cranberries and lingonberries contain benzoic acid, which has an antiseptic effect. Thanks to the presence of benzoic acid, cranberries and lingonberries can be stored for a long time without spoiling. Some benzoic acid is also found in blueberries.

A small amount of salicylic acid, which has antiseptic, antipyretic, diaphoretic and antirheumatic effects, was found in the fruits of wild strawberries, raspberries, blackberries and brambles. Sorbic and parasorbic acids contained in the fruits of mountain ash inhibit the growth of a number of fungi and bacteria, especially in an acidic environment.

In addition to those listed, fruits and berries also contain (in small quantities) succinic, tartaric, formic, quinic, chlorogenic, caffeic, a-ketoglutaric and some other acids.

Succinic acid is a powerful stimulator of cell and tissue respiration, relieves the toxic effects of a number of medications, normalizes the functioning of the cardiovascular system and liver, and has a beneficial effect on atherosclerosis of the coronary vessels and brain.

Vitamins

The vitamin composition of wild fruits and berries is very diverse.

Fruits and berries contain mainly water-soluble vitamins: ascorbic acid, B vitamins and phenolic compounds (vitamin P). Of the fat-soluble vitamins, only carotene, as well as vitamins K, E and F (polyunsaturated fatty acids) are found in wild-growing raw materials.

It must be emphasized that wild berries and fruits can be of practical importance only as sources of vitamins C, P and carotene. The remaining vitamins are contained in very small quantities and therefore the fruits of wild fruit and berry plants can only serve as additional resources of these substances in the diet.

Vitamin A

The fruits of rowan, sea buckthorn, viburnum, rose hips, cloudberries and some other plants contain fat-soluble orange pigments - carotenoids, which are broken down in the human body (in the liver and small intestines) to form vitamin A. Thus, carotenoids are provitamin A. The absorption of carotene in the body occurs only in the presence of fat. The most physiologically active is B-carotene, which in popular scientific literature is often called simply carotene.

The role of vitamin A is very important. It is part of the visual purple contained in the retina of the eye and determines the normal perception of light. With vitamin A deficiency, visual acuity is impaired, especially at dusk (“night blindness”), growth retardation, weight loss, coarsening, and keratinization of the surface layers of the epithelium of the skin and sebaceous glands and hair follicles are noted. The body's resistance to infectious diseases (especially the respiratory tract) decreases. In recent years, it has been established that vitamin A and carotene play a role in the prevention of malignant neoplasms.

The daily requirement of an adult for vitamin A is 1.5-2 mg (or 3-4 mg of carotene).

In terms of their richness in carotene, the first place should be taken by the fruits of rowan and sea buckthorn. Many varieties of rowan were not inferior in carotene content to the best varieties of carrots. Carotene is well preserved when making canned food.

Wild fruits and berries contain vitamin K1 (phylloquinone). It takes an active part in the process of blood clotting. In recent years, it has been established that phylloquinone plays an important role in the processes of tissue respiration and protein synthesis (in particular, enzymes of the digestive tract). Among wild fruits and berries, sources of vitamin K1 include black currant, blackberry, sea buckthorn, serviceberry, chokeberry, cranberry, rowan and rose hip.

Vitamin E

Vitamin E deficiency entails dysfunction of the reproductive organs (the ability to fertilize is reduced, the normal course of pregnancy is disrupted, spontaneous miscarriages are observed, etc.).

Vitamin E plays an important role in muscle metabolism, takes part in the metabolism of fats, proteins and nucleic acids, and has antioxidant properties.

The daily requirement of the adult human body for this vitamin is 20-30 mg.

Significant amounts of vitamin E are contained in the fruits of sea buckthorn, cloudberry, rowan, chokeberry, rose hip, black currant, and lingonberry.

Vitamin C (ascorbic acid)

The role of vitamin C in the body is very important. It takes a diverse part in metabolism. Ascorbic acid increases the antitoxic function of the liver, inhibits the development of atherosclerosis, participates in the process of hematopoiesis, increases the body's resistance to infectious diseases, etc.

With a lack of vitamin C, there is increased fatigue, decreased performance, increased permeability and fragility of blood capillaries and, in connection with this, bleeding (subcutaneous hemorrhages, bleeding from the gums), loose teeth, etc. Insufficient vitamin C content in the human body is always accompanied by increased susceptibility to infectious diseases.

Wild fruits and berries are one of the most important sources of vitamin C in the diet of the population. An outstanding role in providing the population with vitamin C belongs to rose hips, black currants, sea buckthorn, rowan, and edible honeysuckle.

The daily requirement of an adult for vitamin C is 60-120 mg (depending on the age and condition of the body).

To preserve vitamin C, processing of fruits and berries should be done quickly, use only fresh and good-quality raw materials, and do not use copper and iron utensils (including enameled ones, if the integrity of the enamel is damaged) when processing plant raw materials.

Mineral salts. Mineral compounds

Mineral salts play a huge role in the life of humans and animals, being an important component of blood, lymph, digestive juices and other body fluids. They are part of all organs and tissues, ensuring the normal functioning of numerous metabolic processes.

Salts of organic acids (malic, citric, succinic, etc.), which are part of berries and fruits, are characterized by an alkaline reaction, so they are able to neutralize acidic products formed in the body as a result of metabolism. This is of great importance for maintaining a constant active reaction of tissues and fluids.

This property of fruits and berries acquires a special role in certain diseases (diabetes mellitus, nephritis, etc.), when acidic foods accumulate in the body.

The fruits of wild strawberries, raspberries, blueberries, blueberries, cranberries, black and red currants are rich in potassium salts. Potassium compounds entering the body increase urination and increase the excretion of water and table salt. This property of potassium is used in the treatment of a number of diseases of the cardiovascular system and kidneys. Potassium salts are part of systems that maintain the constancy of the blood reaction. The role of potassium in the transmission of nervous excitation is also great.

Wild fruits and berries are of less importance as a source of calcium and phosphorus salts. Calcium and phosphorus from fruits and berries are absorbed by the human body much worse than compounds of the same elements that come from dairy and other products of animal origin.

Many fruits and berries are rich in iron. Iron takes an active part in the processes of hematopoiesis. Blood hemoglobin contains iron. It is also part of the most important redox enzymes that regulate the processes of tissue respiration. The fruits of blueberries, blueberries, raspberries, currants, blackberries, strawberries, hawthorn, bird cherry, viburnum, rose hips, rowan are distinguished by their high iron content; there is also a lot of it in forest apples and pears.

Microelements

Microelements are minerals that are found in food products in small quantities (less than 1 mg per 100 g of product). Microelements (copper, zinc, manganese, cobalt, iodine, fluorine, etc.) play a very significant role in the life of the body. For example, copper, cobalt and manganese are involved in hematopoietic processes; the presence of certain amounts of iodine in food is necessary for the normal functioning of the thyroid gland, etc.

The fruits of cranberries, blackberries, raspberries, strawberries, wild apples, pears, black currants, blueberries, and viburnum are characterized by a high copper content. Significant amounts of manganese are found in lingonberries and blackberries, iodine is found in chokeberries, cranberries, black and red currants, and strawberries. According to the cobalt content, the fruits of strawberries, raspberries, viburnum, wild apple and pear stand out.

The appearance, color, smell and taste of individual varieties of fruit depend on the chemical composition, degree of ripeness, climatic conditions of growth, etc. The characteristic chemical composition of fruit determines their main characteristics, methods of consumption, storage, and, consequently, appropriate preservation methods. Therefore, in order to gain a deeper understanding of some of the processes occurring in raw fruits during their storage, transportation, and canning, it is necessary to know the main groups of elements that make up their composition.

Fruits are composed of various inorganic and organic substances. Most of the mass in fruits is water, which accounts for 75 to 90% of their volume. The main portion of water, which is relatively easily removed by squeezing, pressing, drying, etc., is called free water. The rest of the water is tightly bound to other substances that make up the fruit, so that it cannot be completely removed either by pressing or even by drying. Bound water, or water in a bound state, makes up 10-20% of the total moisture.

After removing the water by intensive drying, what remains is dry product, where the chemicals present in a given fruit variety are concentrated. The dry product makes up 16% of the fresh fruit. If, for example, a dry product is burned (that is, when all organic substances are completely oxidized), ash remains, accounting for approximately 0.5% of the fresh weight of the fruit. Mineral substances such as sulfur, phosphorus, potassium, calcium, sodium, magnesium, iron, silicon, and chlorine are preserved in the ash. And although all of the listed minerals are important for the development of the body, the leading role still belongs to calcium, phosphorus and iron.

The chemical composition and content of vitamins in fruits are given in table. 1.

* (ME - international unit corresponds to 0.025 microgram (μ).)

In addition, fruits are rich in microelements, such as copper (about 0.1 μg%), boron, iodine, zinc, tin, etc. Among organic substances, fruits contain mainly saccharides, vitamins, coloring and tannins, organic acids, proteins, fats, etc.

Sugar carbohydrates make up the bulk of the dry fruit product and are the main carrier of energy materials and the taste sensation of sweetness. Fresh fruits contain about 15% carbohydrates. These are easily soluble simple types of various sugars: glucose (grape sugar), fructose (fruit sugar) - from 3 to 12% and sucrose (beet sugar). In addition, the fruit contains small amounts of sugar alcohols, especially sorbitol. Other carbohydrates (types of complex sugars) are relatively abundant in fruits: they mainly make up the cell walls of fruits and vegetables. Along with a very small amount of starch, fruits contain many other carbohydrates, in particular pectin (about 1%), hemicellulose and cellulose (from 1 to 1.5%), on which, although they are not absorbed by the body, the body largely depends on regulation of the digestive tract.

Fruits contain a sufficient amount of substances genetically related to carbohydrates, primarily organic acids, or glycosides, coloring and tannins. They are called substances of secondary origin, because they are formed in plants from primary products, that is, from sugars during photosynthesis through the oxidation of carbon dioxide. These substances are highly soluble, easily absorbed into tissue and, like carbohydrates, participate in the metabolic process in our body.

Fruits contain malic, citric, tartaric and other acids. The amount of acid in almost all fruits does not exceed 1%; Lemons (up to 6%) and currants (up to 2.5%) contain the most acid. Organic acids, which give the fruit a sour taste, promote digestion. Organic acids play an important role when processing fruits using the canning method, since their ability to suppress the vital activity of microorganisms is used.

Vitamins belong to one of the main components of fruits. These are mainly various organic substances found naturally in living nature in extremely small quantities. In plants that synthesize them, they participate in various biochemical processes, being, as is well known, a necessary component of nutrition for both animals and humans. Vitamins are divided into groups according to their solubility in water and fat; depending on this, their role and function for the human body and its proper nutrition are determined. The functional significance of fat-soluble vitamins is limited, while water-soluble vitamins are involved in the metabolism of the entire body.

Fat-soluble vitamins include vitamins A, D, E and K.

Vitamin A (retinol) is found in fruits in the form of provitamin - carotene. For some varieties, the presence of carotene is determined by the orange color of the fruit (apricots, rose hips), sometimes this color is hidden by chlorophyll.

In the liver, enzymatic breakdown of carotene into active vitamin A occurs. The amount of vitamin A obtained from carotene depends on its chemical characteristics and enzymatic activity, which is not too high in humans. Despite the low percentage of vitamin A in free form in fruits, taking into account the high level of carotene, it plays an important role in ensuring normal growth of the body.

Vitamin D (calciferol) is not found in fruits either in free form or in the form of provitamins (sterols).

Vitamin E (tocopherol) is most often found in green leaves of plants: its concentration in fruits has not yet been precisely established.

Vitamin K (an antihemorrhagic vitamin) forms some naphthoquinone derivatives. A person replenishes this vitamin with products of the microflora of the digestive tract, partly with food. Fruits, compared to vegetables, contain significantly less of this vitamin (strawberries and rose hips only 0.1 mcg%).

The second group of vitamins that dissolve in water includes B vitamins, vitamin C, and more recently vitamin P has also been included here.

Among the B vitamins there are substances that differ in their chemical composition: B 1 (thiamine), B 2 (riboflavin), PP (niacin), B 6 (pyridoxine), H (biotin), Vs (leaf acid), B 12 ( cobalamin) and Bx (pantothenic acid), of which thiamine and riboflavin should be distinguished first of all. And although the content of these last two vitamins in fruits is small (see Table 1), their importance cannot be underestimated. By consuming vegetables and fruits, our body provides about 10% of these very necessary vitamins.

Vitamin C is the most important active substance in fruits. In terms of its chemical composition, it is ascorbic acid; it is easily oxidized, and at the very first reaction it turns into dehydroascorbic acid, which is even more biologically active. With further oxidation, substances that are slightly active are formed. The ability of vitamin C to quickly oxidize leads to significant losses of this valuable substance due to improper processing of fruits and vegetables at home and canning.

Vitamin C is found in almost all types of fruit (see Table 1). The greatest amount of it is found in rose hips, black currants and citrus fruits.

Vitamin P in fruits is usually inextricably linked with ascorbic acid, since it promotes its active participation in metabolism.

Squirrels with amino acids in free form make up the bulk of the nitrogenous substances of fruits. Their content is relatively small; for example, protein in raw fruits amounts to barely 0.5% of the mass. Garden and hazelnuts are richest in proteins (about 15%).

Fats, like proteins, are found most in nuts (approximately 50%). Fruits are not rich in fat - only 0.2 to 0.3%.

Tannins They give fruits a tartness, bitterish and astringent taste, in appropriate proportions, in particular apples, they harmoniously complement the sweet and sour taste. In the presence of oxidative enzymes, tannins quickly oxidize, changing color - fruits darken (green peel of nuts, cut apple), which negatively affects the quality of the finished product (change in color of syrup, compote, etc.).

The pleasant and characteristic smell inherent in many types and varieties of fruits is the result of the presence in them of the so-called aromatics, which have recently become the subject of careful study. These substances consist mainly of alcohols, aldehydes, various essential oils and other specific compounds.

Fruits containing large amounts pectin substances, are used primarily for making marmalade, jams and jellies. Pectin substances are found in large excess in unripe fruits, as well as in gooseberries, currants and apples. To make up for the missing amount of natural pectin, various seasonings (petose) are usually added during processing, as well as, if necessary, less ripe fruits.

Chemical composition of fruits and vegetables

Fruits and vegetables contain water-soluble and water-insoluble substances, most of which are very important in human nutrition.

Carbohydrates are the main part of the dry matter of cell sap (up to 90% of the dry residue).

Fruits and vegetables contain glucose, fructose, and in smaller quantities sucrose and other sugars.

Glucose (SbNlgOb) is grape sugar, mostly found in many fruits and vegetables.

Fructose is found in many fruits and has the same chemical composition as glucose.

Sucrose (C12H22O11) is also found in many fruits and vegetables, especially large amounts of it are found in sugar beets. Under the action of the enzyme invertase, it is broken down into glucose and fructose. This occurs in acidic solutions when heated. This process is called inversion and it proceeds according to the following equation:

C12H22OC + H20 = C6H1206 + CeH12Ob.

Sucrose Water Glucose Fructose

The resulting mixture of glucose and fructose solutions is called invert sugar.

Carbohydrates play an important role in shaping the taste of canned foods. The sweetness of sugars varies. If we take the sweetness of sucrose as 1.0, then the sweetness of fructose is 1.73, and that of glucose is 0.54, and their mixture (invert sugar) is about 1.3.

Another important property of carbohydrates, which determines the technological process for the production of canned food, is their ability to react with amino acids and form dark-colored compounds - melanoidins. In most cases, this is an undesirable process, for example, during heat treatment of juices, cooking pasta, jam, jam.

Among carbohydrates, starch plays an important role. This is a complex chemical compound; in its generalized form, its chemical formula has the form (SbHu05)n. Potatoes (from 12 to 25%), green peas and corn contain a significant amount of it. The fruit contains less than 1% starch. In plant cells, starch has the form of grains that consist of amylase, which is water soluble, and amylopectin, which swells and forms a paste.

Starch is saccharified under the influence of enzymes (amylases). An example would be heavily chilled or frozen potatoes, which have a sweet taste.

The cell wall consists of cellulose, which has the same chemical composition as starch, but a different structural structure.

The amount of fiber in vegetables is 0.2-3%, in fruits from 0.5 to 2%. Fiber ensures the stability of fruits during transportation and storage, prevents them from softening and boiling during sterilization, but complicates the processes of evaporation, wiping and squeezing juice.

Many fruits and vegetables contain pectin substances, which are derivatives of carbohydrates. They play an important role in the production of canned food such as jelly, jam, marmalade. Pectin substances are mainly represented by insoluble protopectin contained in the cell membrane and water-soluble pectin. When fruits ripen, insoluble protopectin, under the influence of the enzyme pectosinase, turns into pectin, soluble in cell sap, and the fruits become softer. The process of converting protopectin into pectin when heated in the presence of acids is used in canning fruits and vegetables.

Apples, quince, some varieties of pears, plums, gooseberries contain up to 1.5% pectin substances, less in apricots, red currants and almost 2 times less in cherries and strawberries. They are found in some types of vegetables - carrots, pumpkin, cabbage, etc.

Organic acids are found in all fruits and vegetables and, together with sugars, determine their taste. Potatoes and root vegetables contain extremely small amounts.

Various fruits and vegetables contain predominantly one or another organic acid. For example, in grapes - wine (0.2-1.0%), in sorrel - from 0.5 to 1% oxalic. In apples and other fruits, malic acid predominates, in lemons and other citrus fruits - citric acid (up to 6-8%).

Nitrogenous substances, although they are contained in fruits and vegetables, due to their insignificant amount, cannot serve as a source for providing complete protein nutrition. However, they are of particular importance in shaping the taste of the product and affect the quality of canned food during their production.

Most fruits and vegetables contain nitrogenous substances (proteins, amino acids, amines, amides, etc.) on average up to 1.5%, green peas - up to 5%, legumes - up to 25%.

Vitamins are the most important component of fruits and vegetables. Although their content in fruits and vegetables is insignificant, they play an important role in metabolic processes. Some vitamins, such as C, are not synthesized by the human body, and their intake from food is mandatory. Therefore, from this point of view, fruits and vegetables are indispensable components of nutrition. Lack of vitamins (hypovitaminosis) leads to serious impairment of human vital functions, and lack of vitamins (vitaminosis) can lead to serious diseases.

Almost all currently known vitamins are found in fruits and vegetables, with the exception of vitamins B12 and D.

The main vitamins contained in fruits and vegetables are as follows:

vitamin A (retinol) is formed in the body from carotene, which is rich in carrots, apricots, and tomatoes (2-10 10 ~ 3%). This vitamin is necessary for the human body for normal metabolism;

Vitamin Bi (thiamine) is found in most fresh fruits and vegetables (0.1-0.2 10~3%). Lack of thiamine in food causes disturbances in carbohydrate metabolism;

vitamin B2 (riboflavin) is found in vegetables (cabbage, onions, spinach, tomatoes, etc.) - 5-10 10~3%. Vitamin B2 deficiency in humans is characterized by inflammation of the oral mucosa and impaired vision;

Vitamin B6 is found in pumpkin and beets (0.1-0.3 10~3%).

Vitamin C (ascorbic acid) is one of the common vitamins. It takes part in redox processes and prevents scurvy. Rose hips (200-450-10~3%), sweet peppers (200-250-10~3%), black currants (up to 200 mg per 100 g) are very rich in vitamin C.

Vitamin C is highly soluble in water, is actively exposed to air, and is destroyed by heat. These features should be taken into account when carrying out the technological process.

Fruits and vegetables contain vitamins PP, P, E, Ks

Most vitamins can be destroyed to one degree or another during the processing of raw materials.

It should be taken into account that water-soluble vitamins, such as C, P, Bi, Vb, PP and pantothenic acid, are lost when washing raw materials, especially when blanching in warm water.

Vitamins Bb and C are not resistant to sunlight. Heavy metals contribute to the destruction of vitamins. With short-term heating, which ensures some removal of air from the intercellular spaces and inactivation of the enzyme system, vitamins are preserved in the processed product.

Tannins impart an astringent taste to fruits and vegetables. They are rich in quince (up to 1%), sloe (up to 1.6%), dogwood (up to 1.2%), wild apples (up to 0.6%), in other fruits - 0.1-0.2% . Vegetables contain very little tannins.

Tannins, when in contact with atmospheric oxygen under the action of the enzyme peroxidase, are oxidized, forming dark-colored substances phlobaphenes. This is what causes the darkening of the surface of the cut fruits.

To prevent darkening of fruits, it is necessary to limit contact of fruits with air or take measures to destroy the enzymatic system (heat treatment or chemical exposure).

Tannins can react with proteins, forming tanates - insoluble compounds.

Dyes (pigments) give different colors to fruits and vegetables. One of the representatives of this class of substances is chlorophyll. It provides green color to unripe fruits and plant leaves. Chlorophyll contains magnesium in its molecule, which can be replaced by hydrogen in an acidic environment. In this case, pheophytins are formed that have an olive-brown color. This is observed when cucumbers and leafy vegetables are sterilized in vinegar.

Coloring substances include anthocyanins, which give fruits and vegetables their color from pink to purple. They are found in dark-colored grapes, black currants, lingonberries, beets, etc.

Red grapes contain enine, which, upon hydrolysis, breaks down into glucose and enidine. Keracyanin is found in cherries. It contains glucose, rhamnose and cyanidin. Beets contain betaine, which consists of glucose and the nitrogen-containing aglucone betanidin.

Yellow pigments called flavones are often found in plants. Flavone derivatives include quercetin, found in onion peels.

Anthocyanins are soluble in water and, when heated and oxidized by air, can be destroyed and change their color (for example, the coloring substances of strawberries, plums, cherries, root vegetables). At the same time, heat treatment has almost no effect on the color change of black currants, since the oxidation of anthocyanins is inhibited by ascorbic acid, which primarily absorbs air oxygen.

Anthocyanins in the presence of metals can also change their color. When canning dark-colored fruits in metal containers with insufficient varnish coating, anthocyanins combine with tin and give the fruits an unusual blue or purple hue. Aluminum causes purple discoloration in cherries and sweet cherries, but does not affect the color change in dark-colored grapes.

The pigments that give fruits and vegetables their color with shades from yellow to red include carotenoids - carotene, lecopene, xanthophyll.

Carotene is provitamin A and is found in carrots, tomatoes, apricots, citrus fruits, and green vegetables.

Lycopene is a red coloring substance found in tomatoes and rose hips.

Xanthophyll accompanies carotene and also gives the yellow color to some fruits (for example, yellow tomatoes) and leaves.

Essential oils have a certain significance in the formation of the organoleptic properties of canned products.

Contained in the skin, leaves and seeds of various fruits and vegetables in very small quantities, but their aromatic activity is very high. In citrus fruits, the skin cells are filled with essential oils, the content of which ranges from 1 to 2.5%, while in apples it is 0.0007-0.0013%. Nevertheless, the aroma of apples with such a quantity of essential oils is very noticeable.

Spicy vegetables are very rich in aromatic substances - parsley, celery, dill, basil, etc. They contain up to 0.5%, sometimes up to 1%, essential oils.

Essential oils are a mixture of terpenes, alcohols, aldehydes, terpene derivatives - citral, carvone, pinene, etc.

Some essential oils have bactericidal properties. Such substances are called phytoncides. Typical representatives are garlic phytoncides (allicin) and allylic (mustard) oil. Coloring substances - anthocyanins of intense red-blue tones - also have bactericidal properties. Carrots, tomatoes, onions, horseradish, peppers, and dill exhibit high phytoncidal properties when heated.

Enzymes are catalysts for complex biochemical processes that occur in a plant cell. These substances have a complex protein structure. They sometimes contain a non-protein group - a coenzyme. Each enzyme catalyzes a specific chemical reaction. All enzymes are divided into the following classes:

Oxidases are redox enzymes that promote the movement of hydrogen from one organic compound to another under the influence of atmospheric oxygen;

transferases - enzymes that catalyze the transfer of chemical groups (phosphoric acid residues, monosaccharides, amino acids, etc.);

hydrolases - enzymes that catalyze the hydrolytic breakdown of complex compounds into simple ones (amylase, esterase, protease

lyases - enzymes that catalyze the non-hydrolytic breakdown of complex compounds (carboxylase, etc.);

isomerases - enzymes that accelerate the isomerization reaction;

ligases (synthetases) are enzymes that catalyze the joining of two molecules.

For most enzymes, the optimal operating temperature is 30-40°C. At the protein coagulation temperature (65-70°C), enzymes are inactivated. This process is called inactivation. Of particular importance for the action of enzymes is the active acidity of the product, i.e., the pH of the medium.

Fats are contained in the plant tissue of fruits and vegetables in small quantities. However, they are of great importance as they regulate metabolism. Fats are insoluble in water and are hydrophobic, due to which they affect the permeability of the cell cytoplasm. Being reserve nutrients, they are deposited in seeds, where the fat content reaches 30-40%. Vegetable oils contain linoleic and linolenic acids, which are well absorbed by the body. The highest fat content (up to 30%) is found in olives.

Glycosides are compounds of carbohydrates (pentoses, hexoses) with alcohols, aldehydes, phenols and other substances. A representative of these compounds is amygdalin. Amygdalin is found in the seeds of stone fruits, giving them a bitter taste and the smell of bitter almonds. When hydrolyzed in the human body, amygdalin releases hydrocyanic acid. The reaction equation looks like this:

С20Н27НОп + 2Н20 = 2С6Н1206 + С6Н5СНО + HGN.

The glycoside solanine is found in tomatoes, eggplants and potatoes. In (unripe) potatoes, solanine is found mainly in the skin and the layer adjacent to it.

The composition of potato solanine is determined by the formula C45H71NO15. In eggplants that have reached the physiological stage of maturity, solanine M (C31H51NO12) accumulates, giving a specific bitter taste. Ripe tomatoes contain 0.004-0.008% solanine. This amount does not cause a bitter taste. Solanine is found in noticeable quantities in green tomatoes.

Naringin is found in the skin and subcutaneous white layer (albedo) of citrus fruits, giving them a bitter taste. As naringin ripens, under the action of the enzyme peroxidase, it breaks down into sugars (glucose and rhamnose) and the aglucone naringinen (C15H12O5), which does not have a bitter taste.

Lingonberries and cranberries contain the glycoside vaccinin, parsley contains apnin, and unripe apples, cherries, plums, and currants contain glucosuccinic acid.

Minerals are part of the structural elements of the cell. The amount of minerals can be determined by the ash content, i.e. the amount of ash after combustion. Fruits and vegetables have an ash content of 0.2-1.8%.

Minerals are divided into macroelements (potassium, calcium, phosphorus, sodium, magnesium), contained in the ash in quantities of at least hundredths of a percent, and microelements (iron, copper, zinc, iodine, bromine, aluminum, cobalt, boron, etc.) , the content of which does not exceed thousandths of a percent. %

Most of the macroelements contain potassium, which increases the water-holding capacity of protoplasm.

Have different chemical compound. When exposed to dilute acids, they dissolve, breaking down into various sugars.
Copper is found in many fruits And berries, seeds and fruits legumes, vegetables,. potatoes and especially in dry apples and pears.

Vegetables And fruit. Rational human nutrition is impossible without vegetables And fruits.
In my own way chemical composition they are close to vegetables and products of animal origin.

Drying fruits And vegetables. Drying as a type of preparation has its advantages. Firstly, it produces stable food products that can be reliably used throughout the year.