Bread, milk, berries - stored for several hours. Dairy products, sausages- are stored for several days. Fruits and vegetables - stored for several months. Canned food, sugar, grain - stored for years.
During storage, profound changes occur under the influence of microorganisms, weight decreases, quality decreases.
There are 3 product groups:
1) perishable - meat, fish.
2) Well kept, with little moisture.
3) Products containing substances that prevent the development of microorganisms - salty, sugar-containing products.
Storage processes.
1. Physical and physicochemical - occur under the influence of the external environment, temperature, humidity, gas composition, light and mechanical influences.
An increase in temperature accelerates the development of microorganisms and causes melting. A decrease in temperature can cause the mayonnaise to separate, thicken vegetable oils, an increase or release of water changes the mass of the product, dry ones lose flowability, microbiological processes intensify, with a loss of moisture, pasta cracks. Sorption of vapors and gases - absorption of odorous in dry components, aromaticity may be lost during storage - desorption.
Crystallization - jam, honey storage.
2. Chemical processes - without the participation of enzymes - hydrolysis - sugar, protein substances.
1) Oxidation - of edible fats (formation of peroxides).
2) Melanoid formation - an interaction reaction simple sugars with amino acids.
3) The interaction of acids in cans with tin - hydrogen is released.
3. Biochemical processes - under the action of enzymes -
Hydrolases - hydrolysis of high-molecular compounds is carried out:
Amylases - by acting on carbohydrates,
Lipases - for fats,
Protalinases - for proteins.
Oxidoreductase - oxidative action.
Breath. Aerobic respiration - in the presence of atmospheric oxygen. In the process of breathing, the mass of the product decreases.
The rise in temperature intensifies the breathing process. With a change in the environment - anaerobic respiration - fermentation.
4. Hydrolytic processes - decomposition of high molecular weight compounds.
Lipase breaks down fats into amino acids. As the acidity rises, the flour brightens.
5. Biological processes - microbiological - fermentation, decomposition of nitrogen-free substances by various microorganisms.
Mold growth - as a result of the vital activity of mold fungi.
Decay is the decomposition of proteins under the influence of putrefactive microorganisms.
Storage modes and factors affecting preservation.
Refrigeration units and maintenance of parameters.
1) Temperature - affects the development of microorganisms, the activity of enzymes, the rate of chemical reactions. Better to store at temperatures closer to 0, or at negative temperatures.
2) Relative air humidity - the degree of air saturation with steam -%, dry - no more than 75%.
3) Gas environment N2 - 78%, O2 - 21%, CO2 - 0.03%.
4) Illumination - light - has a detrimental effect on microorganisms. Foods with a high fat content are best stored in dark rooms, flour and sugar in light rooms.
5) Ventilation - air exchange. It is necessary to maintain the heterogeneity of the environment, reduce temperature, remove moisture.
6) Packing, placement and transportation. The container is necessary to reduce the loss of mass of the product, maintain its quality, and create sanitary conditions. The container must meet the following requirements: be light, strong, not affecting quality. External container - store products. Inner packaging - sell. Placement should be made taking into account properties.
7) Sanitary requirements.

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  Processes, occurring at storage food products (physical, chemical and biological) factors, influencing on the them... Bread, milk, berries - stored for several hours.


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  Processes, occurring at storage food products (physical, chemical and biological) factors, influencing on the them.
  chemical the composition of grain crops.


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  Processes, occurring at storage goods. For persistence food products influence their chemical them processes: physical, biochemical and microbiological.


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  Processes, occurring at storage food products (physical, chemical and biological) factors, influencing on the them.
  Classification, anatomical structure and chemical the composition of grain crops.


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  Quality concept food products, factors, influencing on the quality.
  Factors, influencing on the quality: 1) Chemical composition, i.e. content of proteins, fats and carbohydrates
  2) Physical sv-va - color, appearance, shape, size, strength characteristics.


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  At storage flour occur The same processes that and at storage others products – chemical, biochemical, microbiological ... With varying intensity, which depends on the moisture content of the flour and conditions storage.


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  Chemical and biological
  Processes, occurring at storage goods.
  general review chemical composition food products.
  Factors, influencing on the


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  Processes, occurring at storage goods. For persistence food products influence their chemical composition and intensity of flowing in them about. Classifiers - concept, application.


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  Chemical and biological properties of raw materials.
  Processes, occurring at storage goods.
  general review chemical composition food products.
  Factors, influencing on the quality food products.


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  Processes, occurring at storage goods. For persistence food products influence their chemical composition and intensity of flowing in

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At a temperature of 35-40 ° C, protein denaturation, and at temperatures above 70 ° C - coagulation, or clotting. V as a result of these processes, proteins lose their ability to dissolve and retain water.

When cooking meat broths a certain amount of protein passes into the water, which coagulates in the form of flakes and accumulates on the surface. If the water is salted after boiling, only water-soluble proteins will go into the solution, and salt-soluble proteins will mostly remain in the meat. When cooking fish, salt has a lesser effect on protein loss.

To obtain broths, the meat is dipped in cold water and boiled at a low boil, in this mode more extractives are transferred into the water. For second courses, the meat is dipped in hot water, bring to a boil and cook without boiling, in this mode proteins retain more moisture, less extractive substances and proteins go into solution.

Prolonged heating of proteins leads to secondary changes in the protein molecule, as a result of which their digestibility decreases.

Part of the fat is melted during cooking of animal products. During the cooking process, this fat breaks down into tiny balls, and the more intense the boil, the more fat. emulsifies(decays). The acids and salts of the broth decompose this fat into glycerin and fatty acids, which make the broth cloudy with an unpleasant odor and taste. For this reason, boil the meat at a moderate boil, and collect the fat that accumulates on the surface of the broth.

Frying changes the fat more deeply. At temperatures above 180 ° C, fat breaks down into tarry and gaseous substances, which dramatically impair the quality of the food. A sign of this process is the appearance of smoke. It is necessary to fry at a temperature just below the smoke point. The evaporation of water when the fat is heated causes splashing of the fat. This fat loss is called waste.

When frying, part of the fat decomposes with the release of acrolein, some of which dissolves in the fat and gives it an unpleasant taste and smell, the other part evaporates with smoke.

Deep-fried food changes fat through prolonged exposure to high temperatures and particle contamination. Part of the fat is oxidized by atmospheric oxygen, forming substances harmful to the body. To prevent this phenomenon, special deep fryers are used, in the lower part of which the temperature is much lower and the product particles, falling to the bottom, do not burn. In addition, products intended for deep-frying are not breaded in flour, and deep-fat is periodically filtered.

Undergoes noticeable changes butter, so it is better not to use it for frying, but to introduce it into sauces and ready meals when serving.

When starch is heated with water to a boil, gelatinization of carbohydrates occurs - the formation of a gelatinous mass.

The starch of potatoes is gelatinized during cooking due to the moisture contained in the potatoes itself, and the starch of dough products is due to the moisture that is released by coagulated gluten proteins. The same process is observed when cooking pre-soaked legumes.

An increase in the mass of dry products (cereals, pasta) during cooking is explained by the absorption of water by the gelatinizing starch contained in these products.

Sugar from fruits and berries, as well as sugar added when cooking jelly and compotes, is broken down by acids into glucose and fructose, which are sweeter than the original sucrose.

When sugar is heated to 140–160 ° C, it decomposes with the formation of dark-colored substances. This process is called caramelization... The resulting product is called burnt and is used for coloring sauces and other products.

Vegetable products soften during heat treatment, which increases their digestibility. The main reason for softening is that protopectin and other insoluble pectin substances of cells pass into soluble pectin, and fiber, the main material of plant cells, swells, becomes porous and permeable to digestive juices.

Vitamins A, D, E, K, which dissolve in fat, are well preserved. For example, sautéing carrots almost does not reduce their vitamin value, and carotene is more easily converted to vitamin A.

B vitamins are stable when heated in an acidic environment, but are destroyed by 20-30% in an alkaline and neutral environment. It should be remembered that vitamins of this group are water-soluble and easily transform into a decoction.

Vitamin C is destroyed most strongly. This is due to its oxidation with atmospheric oxygen. They catalyze the oxidation of salts of heavy metals (copper, iron) and enzymes contained in products. Avoid contact of vegetables with iron and copper. And for the destruction of enzymes, vegetables must be immediately immersed in hot water. Retains vitamin C in vegetables and fruits in an acidic environment.

Heat treatment practically does not change minerals, some of them pass into the broth, which is used to make soups and sauces.

Colorants are also converted by heat treatment. Chlorophyll of leafy vegetables is destroyed, forming brown-colored substances. Beet pigments acquire a brown hue, therefore it is advisable to create an acidic environment and increase the concentration of the broth to preserve the color of the beets. Carotene in carrots and tomatoes is resistant to heat treatment, which is widely used in cooking for coloring dishes. Anthocyanins of plums, cherries, black currants are also resistant to heat treatment.

BOUILLONS AND SOUPS

The liquid base of soups is broths, milk and dairy drinks (kefir, yogurt), decoctions of cereals, vegetables, fruits, and kvass. The liquid part of the soup contains flavoring and aromatic substances that stimulate the appetite and promote better absorption of food.

For a side dish, or filling, a variety of products are used: vegetables, mushrooms, cereals, legumes and pasta, fish, meat, poultry, etc. The dense part of the soup contains nutrients: proteins, fats, carbohydrates, minerals, vitamins.

The reasons for the change in the quality of food products are various processes occurring at the stages of transportation, storage and sale. With the controlled flow of these processes, the quality of some goods can improve over a certain period of time (for example, when ripening tomatoes, bananas, winter varieties of apples and pears, when cheese, meat and salted fish ripen, aging vintage grape wines, cognacs, whiskey). However, in most cases, the processes occurring lead to undesirable changes in quality and are the cause of product losses. Depending on the nature of the occurrence, all processes can be subdivided into physical and physicochemical, chemical, biochemical, microbiological and biological.

Physical and physicochemical processes proceed under the influence of environmental factors (temperature, relative humidity of air, light, gas composition) and humans (mechanical stress). These include sorption processes, processes of crystallization of sugars, aging of proteins and starch, changes in the dispersity of colloidal systems, deformation processes, etc.

Sorption processes - these are the processes of absorption (sorption) or evaporation (desorption) of water vapor, as well as other substances and gases.

The absorption of moisture leads to the moistening of hygroscopic products and, as a result, their loss of flowability, caking (sugar, salt, flour, starch, etc.), softening and deformation (cookies, gingerbread, crackers, drying, etc.), a change in the state of the surface (for caramel , marmalade, marshmallow, marshmallow, halva for

the surface becomes sticky). The absorption of volatile fragrances can lead to odors that are not specific to the product.

Evaporation of moisture causes drying processes (staling of bread, flour confectionery, shrinkage of frozen meat and fish, etc.), wilting and shrinking (fresh fruits, vegetables and mushrooms). As a result of the desorption of volatile substances, the product loses its characteristic odor (aroma).

The intensity of sorption processes increases with sudden changes in temperature and relative humidity of the air, in case of non-observance of the rule of commodity neighborhood, violation of the integrity of the package.

Crystallization of sugars- a process typical for honey, some fruit and berry confectionery (preserves, jams, marmalades, etc.), ice cream.

The process of crystallization or "setting" of honey is accompanied by its transition from a liquid to a crystalline state. The ability to crystallize is considered a sign of good natural honey. Ripe high quality honey crystallizes solid homogeneous mass... Layering of honey during crystallization indicates, as a rule, its immaturity. Honey falsified by the introduction of starch syrup does not crystallize. The storage temperature of honey affects the rate of its crystallization and the size of the resulting glucose crystals.

Candying of preserves, jams, marmalades, fondant sweets is an unacceptable defect that leads to the appearance of a rough, non-uniform consistency.

With temperature drops during ice cream storage, the size of ice crystals and lactose increases due to recrystallization processes. The consistency of the ice cream becomes more dense, coarse, "gritty".

Aging of proteins and starch accompanied by a decrease in their water-holding capacity. Aging of proteins (syneresis) leads to delamination of yogurt, kefir and other liquid fermented milk products during storage. Aging of starch is the cause of irreversible physical and chemical changes during staling of bread, long-term storage cereals and pasta (the cooking time increases to readiness, the weight and volumetric weld decreases).

Change in the dispersion of colloids causes clouding of grape and fruit wines, beer, discoloration of some soft drinks... The appearance of drinks deteriorates due to a violation of transparency, and in some cases - precipitation.

The reason deformation processes are mechanical influences arising during transportation, storage, repackaging, preparation for sale and other operations related to the movement, storage and sale of goods. Mechanical influences can lead to various damages that worsen the appearance, destroy the internal structure of products, causing quantitative losses (for example, violation of the integrity of the package, breaking eggs, pressing and puncturing fruits and vegetables, crushing berries, curd products, cakes and pastries, crumbling cookies, waffles, scrap pasta, etc.).

This group of processes also includes changes that occur when storage conditions are violated: freezing of potatoes, fruits and vegetables, freezing of fermented milk products, melting of ice cream, thawing of frozen meat, fish, etc.

Chemical processes are a set of chemical reactions that occur in food products without the participation of enzymes and microorganisms. These reactions are activated by environmental factors: temperature, relative humidity, light, etc. The main chemical processes include oxidation and rancidity of fats, non-enzymatic darkening of products as a result of melanoidin formation, the interaction of metals with organic acids.

When storing canned food in a metal container, metal interaction, included in the composition of tin (primarily tin), with organic acids product. Tin salts of organic acids (toxic compounds) accumulate in the product, the hydrogen released as a result of the reaction swells the bottom and lid of the can (chemical bombardment). To prevent chemical bombing of canned food, protective acid-resistant coatings of metal containers (special varnishes, enamels) are used. In canned products, the content of tin salts is standardized: no more than 200 mg per 1 kg of product.

Biochemical processes- these are processes that occur under the influence of the product's own enzymes. The activity of their course depends on the nature of the product, the technology of canning and storage. Biochemical processes include redox, hydrolytic and synthetic processes.

Redox processes occur with the participation of redox enzymes food products: catalase, peroxidase, polyphenol oxidase, etc. Many of them lead to a deterioration appearance and reducing the nutritional value of foods. For example, oxidation of tannins is the cause of enzymatic browning of foods. When vitamin C is oxidized, the biological value decreases, since the oxidized form, dehydroascorbic acid, is easily destroyed.

The set of redox processes occurring in food products that are living biological objects (fresh fruits and vegetables, eggs, unboiled cereals, etc.) is called breathing. When breathing, the main nutrients are consumed - sugars, organic acids, proteins, fats and other compounds, which leads to a decrease in the mass of the product (natural loss). There are two types of breathing: aerobic (in the presence of oxygen) and anaerobic (anoxic). The type of respiration determines the composition of oxidation products, as well as the amount of energy released. At aerobic respiration glucose is oxidized to water and carbon dioxide:

C 6 H 12 O 6 + 6O 2 -» 6H 2 O + 6CO 2 + 688 kcal;

at anaerobic- to ethyl alcohol and carbon dioxide:

S 6 N 12 O 6 - 2C 2 H 5 OH + 2CO 2 + 22.5 kcal.

The resulting heat and moisture create favorable conditions for the development of microorganisms, ethyl alcohol has a detrimental effect on living cells, gives the product a foreign taste and smell.

To reduce the intensity of respiration, an optimal climatic storage regime (temperature, relative air humidity) is maintained, storage technology is used in a controlled or modified gas environment (with a decrease in oxygen concentration and an increase in carbon dioxide concentration, respiration rate decreases). With mechanical damage, physiological and microbiological diseases, damage to products by agricultural pests, the intensity of respiration increases.

Hydrolytic processes- these are the processes of splitting proteins, fats, carbohydrates and other compounds with the participation of hydrolase enzymes (amylase, proteinase, lipase, etc.). They can both positively and negatively affect the quality of food products.

When fruits and vegetables ripen, sweetness increases due to starch hydrolysis, pulp softening due to protopectin hydrolysis, astringent taste softening due to hydrolysis of phenolic compounds. Hydrolytic processes occurring during the ripening of cheeses, meat, fish, during the fermentation of tea, tobacco, have a beneficial effect on the formation of their quality.

At the same time, deep hydrolytic processes are the cause of maceration (destruction) of tissues of fruits and vegetables, the accumulation of free fatty acids as a result of hydrolysis of fats, destruction of proteins, etc.

Synthetic processes- these are the processes of the formation of complex compounds from simpler ones with the participation of synthetase enzymes. These processes are characteristic only for food products, which are living biosystems. Synthetic processes include the process of tissue regeneration with mechanical damage to fruits and vegetables (for example, the process of suberinization of the wound surface with mechanical damage to potatoes), the synthesis of phytoncides and phytoalexins - substances of a protective nature, etc. period before laying potatoes for long-term storage).

Microbiological processes - these are processes that take place with the participation of microorganisms. They are one of the main causes of food spoilage during storage. Microbiological processes include different types fermentation, mold, decay, mucousness, etc. (Table 1.6).

The development of many microorganisms is accompanied by the accumulation of toxic substances in the food product (mycotoxins - with the development of molds, cadaverine and putrescine - with the development of putrefactive bacteria, etc.), as a result of which their safety is lost.

Some types of fermentation are used in food production technology: alcoholic fermentation - in the production of alcohol, grape wines, beer, bread from wheat flour; lactic acid - in the production of fermented milk products, pickled vegetables, rye bread; propionic acid - when ripening cheeses; acetic acid - in the production of food vinegar. In this case, pure cultures of microorganisms are used, and fermentation is carried out under strictly controlled conditions.

Biological processes associated with damage to food by pests (insects, rodents, birds). Pests not only violate the integrity of the product, but also contaminate it with their secretions, carry microorganisms, many of which are causative agents of infectious diseases.

Food products damaged during storage by pests and rodents are not subject to sale and are related in most of the processes considered in parallel, therefore the quality and loss of food products depend on their joint action, orientation and intensity.

At a temperature of 35-40 ° C, protein denaturation, and at temperatures above 70 ° C - coagulation, or clotting. V as a result of these processes, proteins lose their ability to dissolve and retain water.

When boiling meat broths, a certain amount of protein passes into the water, which coagulates in the form of flakes and accumulates on the surface. If the water is salted after boiling, only water-soluble proteins will go into the solution, and salt-soluble proteins will mostly remain in the meat. When cooking fish, salt has a lesser effect on protein loss.

To obtain broths, the meat is immersed in cold water and boiled at a low boil; in this mode, more extractives are transferred into the water. For the second courses, the meat is dipped in hot water, brought to a boil and cooked without boiling; in this mode, proteins retain more moisture, less extractive substances and proteins go into solution.

Prolonged heating of proteins leads to secondary changes in the protein molecule, as a result of which their digestibility decreases.

Part of the fat is melted during cooking of animal products. During the cooking process, this fat breaks down into tiny balls, and the more intense the boil, the more fat. emulsifies(decays). The acids and salts of the broth decompose this fat into glycerin and fatty acids, which make the broth cloudy with an unpleasant odor and taste. For this reason, boil the meat at a moderate boil, and collect the fat that accumulates on the surface of the broth.

Frying changes the fat more deeply. At temperatures above 180 ° C, fat breaks down into tarry and gaseous substances, which dramatically impair the quality of the food. A sign of this process is the appearance of smoke. It is necessary to fry at a temperature just below the smoke point. The evaporation of water when the fat is heated causes splashing of the fat. This fat loss is called waste.

When frying, part of the fat decomposes with the release of acrolein, some of which dissolves in the fat and gives it an unpleasant taste and smell, the other part evaporates with smoke.

Deep-fried food changes fat through prolonged exposure to high temperatures and particle contamination. Part of the fat is oxidized by atmospheric oxygen, forming substances harmful to the body. To prevent this phenomenon, special deep fryers are used, in the lower part of which the temperature is much lower and the product particles, falling to the bottom, do not burn. In addition, products intended for deep-frying are not breaded in flour, and deep-fat is periodically filtered.

Butter undergoes noticeable changes, so it is better not to use it for frying, but to add it to sauces and ready meals when serving.

When starch is heated with water to a boil, gelatinization of carbohydrates occurs - the formation of a gelatinous mass.

The starch of potatoes is gelatinized during cooking due to the moisture contained in the potatoes itself, and the starch of dough products is due to the moisture that is released by coagulated gluten proteins. The same process is observed when cooking pre-soaked legumes.

The increase in the mass of dry products (cereals, pasta) during cooking is explained by the absorption of water by the gelatinizing starch contained in these products.

Sugar from fruits and berries, as well as sugar added when cooking jelly and compotes, is broken down by acids into glucose and fructose, which are sweeter than the original sucrose.

When sugar is heated to 140–160 ° C, it decomposes with the formation of dark-colored substances. This process is called caramelization... The resulting product is called burnt and is used for coloring sauces and other products.

Vegetable products soften during heat treatment, which increases their digestibility. The main reason for softening is that protopectin and other insoluble pectin substances of cells pass into soluble pectin, and fiber, the main material of plant cells, swells, becomes porous and permeable to digestive juices.

Vitamins A, D, E, K, which dissolve in fat, are well preserved. For example, sautéing carrots almost does not reduce their vitamin value, and carotene is more easily converted to vitamin A.

B vitamins are stable when heated in an acidic environment, but are destroyed by 20-30% in an alkaline and neutral environment. It should be remembered that vitamins of this group are water-soluble and easily transform into a decoction.

Vitamin C is destroyed most strongly. This is due to its oxidation with atmospheric oxygen. They catalyze the oxidation of salts of heavy metals (copper, iron) and enzymes contained in products. Avoid contact of vegetables with iron and copper. And for the destruction of enzymes, vegetables must be immediately immersed in hot water. Retains vitamin C in vegetables and fruits in an acidic environment.

Heat treatment practically does not change the minerals, some of them go into the broth, which is used to make soups and sauces.

Colorants are also converted by heat treatment. Chlorophyll of leafy vegetables is destroyed, forming brown-colored substances. Beet pigments acquire a brown hue, therefore it is advisable to create an acidic environment and increase the concentration of the broth to preserve the color of the beets. Carotene in carrots and tomatoes is resistant to heat treatment, which is widely used in cooking for coloring dishes. Anthocyanins of plums, cherries, black currants are also resistant to heat treatment.

During storage in food, changes in quality and weight occur. By their nature, these changes can be biochemical, chemical, biological, physical and microbiological. Knowledge of the processes occurring in goods during storage helps to establish the mode, storage methods, and reduce losses.

Biochemical processes? proceed under the action of enzymes found in the products themselves.

The biochemical processes include respiration, hydrolytic and autolytic processes.

Breath? it is a redox process, in which food nutrients (sugars, organic acids, proteins, fats, etc.) are consumed. As a result, the mass of the product decreases and its the nutritional value... This process takes place only in living organisms, in grain, fruits, vegetables, flour, cereals, eggs.

Breathing can be aerobic (in the presence of oxygen) and anaerobic (oxygen-free). During aerobic respiration, CO2 and H2O are formed and a lot of heat is released, which leads to germination (grain, vegetables), self-heating (flour, grain, cereals), microbiological spoilage (vegetables, fruits). With anaerobic respiration, less heat is generated, but ethyl alcohol accumulates, which gives the food an unpleasant taste (fruit). Breathing cannot be excluded when storing the above products, therefore, try to maintain aerobic breathing.

To reduce its intensity, it is necessary to ventilate the room (remove the generated heat and moisture), reduce the storage temperature and air humidity, and regulate the gas environment.

Hydrolytic processes? cause the breakdown of proteins, fats, carbohydrates under the action of hydrolase enzymes. They affect the quality of the product positively (for example, when fruits ripen due to hydrolysis of starch, sugar accumulates) and negatively (for example, hydrolysis of fat increases the acidity of edible fats, flour, cereals, reducing their freshness).

When storing foods rich in proteins (meat, fish), proteins are hydrolyzed to amino acids. This process (together with the hydrolysis of glycogen to lactic acid) leads to the maturation of meat after slaughter, herring, salmon fish when salted and is called autolysis. Thanks to this, the meat becomes tender, juicy with a characteristic taste and aroma. Autolysis is observed during the maturation of wine, fermentation of tea, coffee, tobacco. Deep autolysis leads to food spoilage. The negative effect of autolysis is manifested when freezing potatoes, sprouting grain, vegetables. At low temperatures, the rate of hydrolytic processes slows down.

Microbiological processes? occur under the action of enzymes secreted by microorganisms. These processes can occur in any food and are one of the main causes of spoilage (food becomes unusable). Microbiological processes include fermentation, decay, and mold.

Fermentation? it is the breakdown of carbohydrates and some alcohols by enzymes. As a result of the vital activity of microorganisms, alcohol, milk, oil, acetic acid, carbon dioxide, etc. Fermentation can be alcoholic, lactic acid, butyric acid, propionic acid, acetic acid.

Alcoholic fermentation occurs in foods rich in sugar and moisture (juices, preserves, jam, jam, fruits, berries). The product becomes cloudy, foams, and acquires an unpleasant taste and smell.

Lactic acid fermentation causes spoilage of milk, lactic acid products, souring wine, beer.

Butyric acid fermentation occurs when storing flour, dairy products, pickled vegetables, cheeses, and canned food. At the same time, a bitter, unpleasant pungent taste, odor and gassing (swelling of cheeses, bombardment of canned food).

Acetic fermentation causes souring of wine, beer, juices, kvass. At the same time, there is a clouding, mucousness, a sour taste appears.

Propionic acid fermentation causes spoilage of wine, dairy, pickled vegetables, causing them to become clouded and mucous. Lowering the storage temperature of food will reduce the rate of fermentation.

Rotting? it is a deep breakdown of proteins under the action of enzymes secreted by putrefactive bacteria. Is this why protein-rich foods rot? meat, fish, egg, cheeses. Does this produce toxic substances? ammonia, mercaptan, indole, skatole, etc. Products acquire a very unpleasant odor and become poisonous.

Mold? occurs when mold fungi develop on products. Products that contain a lot of water or are moistened during storage, in leaky or damaged packaging, are subject to mold: fruits, vegetables, preserves, jam, jam, bread, flour, meat and fish products, butter.

Mushrooms break down sugars, fats of food products, giving them a moldy taste and smell, and form a coating on the surface. In addition, with mold, harmful substances accumulate with carcinogenic effect(mycotoxins). To prevent mold growth, products must be tightly packed in a serviceable container, stored without sudden temperature fluctuations, observing a humidity regime.

Chemical processes? these are various chemical reactions that take place in foods without the participation of enzymes. This is the rancidity and salting of fats under the influence of oxygen, light, water and heat; discoloration (discoloration of wines); chemical destruction of vitamins, chemical bombing of canned food? (the interaction of the metal of the can with the acids of the product with the formation of gases, especially canned food with tomato filling). Chemical processes include rusting of metal cans, which can compromise their tightness. Chemical processes can be slowed down by using packages that protect goods from light, atmospheric oxygen, lowering the storage temperature, and air humidity.

Physical processes? arise in products under the influence of temperature, light, air humidity, mechanical influences. These include:

moisture (salt, granulated sugar, flour, biscuits, crackers, waffles, etc.)? due to the hygroscopicity of the product, water condensation during sudden temperature changes and soaking. At the same time, the product softens or loses flowability, cakes;

drying out (bread, vegetables, fruits, gingerbread)? due to desorption, low air humidity, temperature drops. As a result, the weight of the product decreases, its quality deteriorates;

crystallization of sugar in honey, jam, syrups, chocolate (sugar bloom), stratification of alcoholic beverages, hardening of vegetable oils occurs when low temperatures storage. Physical bombing is possible when canned food freezes.

Mechanical damage to the goods (breakage of eggs and glass containers, deformation of bread, fruits, vegetables, scrap pasta) occurs during careless handling of the goods when working with them, which leads to partial or complete unsuitability of the goods for use.

Physical processes can be slowed down by observing temperature conditions, air humidity, proper packaging, and careful handling of goods.

Biological processes? is it an effect on insect products? pests (mites, beetles, moths) and rodents. Grain flour, confectionery products, food concentrates, dried fruits, etc. are affected. In this case, the products are considered food waste and are not subject to sale. In some cases, they can be sent for processing (potatoes affected by a nematode? Are sent to starch or alcohol).

To prevent damage to goods by rodents and insects, it is necessary to observe the temperature and humidity, sanitary and hygienic storage regime, to disinfect containers, warehouses, vehicles.