Methods for preserving fruits and vegetables. Preservation of fruits and vegetables

Depending on the pre-training raw materials receive canned food, different in taste and purpose. Some of them are used directly for food, others only after preliminary cooking, and some are used as raw materials for cooking marmalade and jams. The following main types of canned food are obtained from vegetables: natural vegetable juices, snack bars, lunch, gas stations, canned food for baby food, diet, tomato products, salted and pickled vegetables. From fruits are obtained: compotes, juices, purees and sauces, fruit preserves for baby food, marinades, sulphated fruits and fruit purees. Canned food is allowed to be produced only according to standards or specifications agreed with health authorities and product consumers. Based on the standards, technological instructions are developed, approved in the prescribed manner. in standards and specifications specify the requirements for the quality of raw materials and materials, physical and chemical (content of solids, salt, sugar, pulp, salts of heavy metals) and organoleptic ( appearance, taste, smell, color, consistency) quality indicators finished products. The standards and specifications specify test methods, established quality indicators, as well as rules for the acceptance and storage of products. In the process of canned food production, enterprises carry out chemical-technical and bacteriological control of production. The specified control is carried out by the laboratory of the enterprise. All manufactured products can be delivered to the consumer only after their quality has been checked by the production laboratory and a quality certificate or certificate has been issued for it. The laboratory also controls the quality of raw materials and materials, including containers and packaging materials, compliance with established recipes, technological instructions, sanitary regulations at all stages of production, storage modes of products in warehouses, quality of design and packaging. The results of chemical-technical and bacteriological control and tasting assessment (organoleptic) are recorded in the journals of a special form.

Transportation, acceptance and storage of raw materials

Depending on the type of raw material, various methods of its delivery to processing enterprises are used. Fruits - apples, plums, cherries, sweet cherries, pears, quince - are delivered to the plant in raw wooden boxes with a capacity not exceeding 16 kg.

For transportation of apples, quinces are also used lattice containers weighing up to 400 kg. It is allowed to transport apples in bulk in dump trucks specially allocated for this purpose, provided that the safety of raw materials is ensured.

For the transportation of berries, wooden boxes with a capacity of up to 12 kg are used, sieves - lubenki 4 - 6 kg. Grapes are transported in bulk in vehicles equipped with special bodies, tractor trailers "boats". Vegetables are delivered to the plant in boxes, containers. For transportation of grain of green peas, wooden dense planed boxes are used. The delivery of green pea grains in water tankers is widely used. For tomatoes, boxes are used, special shelf containers that protect tomatoes from mechanical damage, they also use the method of delivering tomatoes in water. Root crops and potatoes are delivered in containers or in bulk.

Raw materials entering the plant must comply with the requirements of applicable standards and specifications.

Accepted raw materials, depending on their quality condition, are sent for processing or storage. Raw materials are stored in covered raw material sites or in a dry, well-ventilated room with a cement or asphalt floor or in cold stores.

Each batch of raw materials received for storage is provided with a label indicating the date of receipt at the plant. The shelf life of raw materials depends on the type of raw materials and storage method.

After storage, the raw materials are fed to the workshop for processing in the order they are received and taking into account the actual state. The container released from under the raw materials is subjected to sanitary treatment, it is cleaned of the remnants of raw materials, washed hot water and scalded with steam. Instead of steaming, boxes can be treated with water containing 50-200 mg of active chlorine per 1 liter of water, followed by rinsing with clean water.

The containers for the transportation of green pea grains, tanks for the transportation of tomatoes and their pulp are especially carefully processed. For this purpose, the factories have specially equipped sites with hot water and steam supply.

Sorting, calibration and inspection of raw materials

The raw materials arriving for processing are sorted by color, grade, degree of maturity and calibration. Sorting and sizing of raw materials according to the indicated characteristics has importance; Thus, the homogeneity of raw materials makes it possible in the future to establish certain technological modes of production and obtain products that are uniform in quality. In addition, the current standards for canned food stipulate uniformity in size, color, etc. Simultaneously with sorting, inspection of raw materials is carried out - removal of damaged by diseases and pests, unripe or overripe fruits. Sorting and sizing processes are carried out both manually and with the help of machines. For sizing cherries, sweet cherries, plums, apricots, inspections are carried out manually behind inspection conveyors, which are belt or roller conveyors.

Washing, cleaning, cutting and crushing of raw materials

Raw materials of all kinds, except for especially tender berries (strawberries, raspberries, etc.), are washed to remove contaminants. Washing of raw materials also ensures the removal of residues of pesticides from the surface of the fruit and reduces the microbial contamination of raw materials. Washing machines of various systems are used for washing, which ensure the flow of water, timely draining of its upper layer, and periodic removal of contaminants settled to the bottom. Water used for washing raw materials must comply with the requirements of the state standard for drinking water. Washing machines, as a rule, are equipped with shower devices, where the washed raw materials are rinsed. Shower devices are used to wash berries. When processing various kinds raw materials, various methods of preparing raw materials are used to remove the skin, seeds, stalks. and operations are carried out on various machines. Destalking of fruits on destalk machines, where the fruits are fed onto rotating rubber rollers arranged in the same plane.

Pneumatic onion peelers are used to peel onions, where cleaning is carried out under the influence of compressed air and mechanical agitation, and the peel is sucked off by a fan. For peeling potatoes, carrots and other root crops, machines are used that are built on the principle of friction of processed root crops against rough surfaces of a rotating grater disk and a working cylinder covered with an abrasive mass. To separate tomato seeds, a complex of machines mounted on one frame is used, where the following operations are performed: pressing tomatoes, squeezing the juice and rubbing the crushed mass. Cutting various root crops into bars, cubes, mugs is carried out on vegetable cutters of various systems.

In the production of compotes, jams, preserves, machines are used to remove the seed nest and cut apples and pears into slices. Stones from fruits are removed on stone-beating or rubbing machines To obtain puree-like semi-finished products, juices with pulp, extractors and rubbing machines are used. Fine grinding of products, a high degree of dispersion is achieved by homogenization. The process is carried out on homogenizers, colloid mills, etc.

Carrying out the cleaning processes of fruit and vegetable raw materials, performed by machines, is usually accompanied by a manual cleaning process. When cleaning, the remnants of the skin, eyes, etc. are removed.

Blanching

Blanching is a short-term heat treatment of raw materials at a certain temperature regime steam in water or aqueous solutions salts, sugars, organic acids.

The purpose of blanching is to inactivate the action of enzymes that are part of all types of raw materials. When storing prepared raw materials, enzymes continue their action and accelerate oxidative processes that lead to deterioration or deterioration in the quality of prepared raw materials (darkening of the pulp of fruits and vegetables, etc.).

When heated to a temperature of 70 ° C and above, the enzymes are destroyed and their undesirable action stops.

When blanching fruits and vegetables, the degree of their purity increases, microbial contamination decreases, the volume of fruits and vegetables decreases due to the fact that air is removed from the fruit tissue when heated; the texture of the fruit becomes elastic. The last two circumstances facilitate further stacking of fruits in jars.

During transportation, blanched vegetables are less damaged. Blanching is carried out in some cases to remove unwanted odors and tastes (bitterness, etc.), in some cases, substances that form mucus and foam are removed.

Processing modes and equipment used for this process depend on the type of fruits and vegetables.

When blanching in water, along with positive changes in the product, there is a loss of valuable nutrients - sugars, mineral salts, water-soluble vitamins; Therefore, blanching is often used in steam or in sugar solutions, the latter are then used in the production of canned food.

Roasting and sautéing

To give certain types of canned food certain organoleptic qualities vegetables are fried or sautéed.

Roasting vegetables is the heat treatment of vegetables in fats to reduce the mass of raw materials by more than 30% at a certain temperature regime to give them a specific taste and color and increase calorie content.

Sauteing vegetables - light frying of vegetables with a weight reduction of up to 30%. Roasting of vegetables and root crops is carried out in steam-oil ovens and stoves. Krapivina, two-body boilers in fat (vegetable or animal) at a temperature of 120 - 140 ° C.

When roasted, moisture is removed from vegetables and fat is absorbed, vegetables lose their characteristic fresh elasticity, a golden crust forms on the surface of the vegetables, giving the fried vegetables a specific taste.

When roasting, a significant amount of water evaporates, fried products weigh less than raw materials. The difference in the mass of raw materials before and after roasting is called visible roasting. Distinguish the true process of frying - the difference between the visible percentage of frying and the percentage of fat absorbed into the vegetables during frying. According to the apparent percentage of frying, the degree of readiness of vegetables is determined and the correctness of the process is monitored.

concentration

In the production of tomato paste, jam, marmalade, condensed milk, concentration is carried out - the evaporation of moisture from the pureed mass of raw materials.

Concentration is carried out in vacuum - evaporators at a rarefaction of about 90 kPa and a temperature of 52 - 50 ° C.

Boiling at such temperatures allows you to get a product High Quality according to taste, color, vitamin content Boiling under atmospheric pressure at a temperature of 100 ° C leads to a deterioration in quality - the product acquires a bitter aftertaste, as a result of caramelization of sugar it darkens.

Pressing

To obtain fruit and vegetable juices, crushed fruit and vegetable raw materials are pressed to separate the liquid phase from the solid. Presses of various systems are used for squeezing juices: hydraulic, screw, screw, etc.

Container preparation

Tin and glass containers are processed before packaging.

Glass jars are inspected, broken and containers with defects (holes, cracks, etc.) are selected, soaked in warm water, washed with detergents, rinsed, re-inspected, looking through each jar going under packaging in front of a light screen, scalded.

Washing modes of cans, temperatures and duration of cleaning solutions depend on the design of the machine, the degree of contamination of the container.

Used as detergents caustic soda, synthetic detergents approved for canned food cleaning by health authorities.

Tin bikes are inspected, continuously or selectively checked for leaks, squirted with hot water and live steam, and sent for filling.

Covers for glass jars treated in boiling water for 2 - 3 minutes, and then with steam at 100 ° C for 20 - 25 minutes.

Barrels are inspected, rinsed, contaminated barrels are washed.

To check the absence of leaks, the barrels are filled with water for 20-30 minutes. When packaging tomato paste, sulphated semi-finished products, juices, pickles and fermentations, the barrels are soaked.

When using polyethylene bags - liners, soaking is not performed. Barrels intended for packaging jam, jam and marmalade are well dried before use.

Product packaging and can sealing

The filling of containers with the product is carried out in accordance with the established requirements for a particular type of product. When packaging, a certain net weight, the ratio of canned food components (filling, syrup, fruits, etc.) must be maintained.

During packaging, the observance of a certain temperature of the product is also controlled. Packaging is carried out on fillers of various systems, as well as manually.

To ensure the safety of products during sterilization, transportation and subsequent storage, filled jars are hermetically sealed.

Capping of glass containers is carried out on seaming machines metal lids equipped with sealing sealing rings. For better conservation quality, it is desirable to remove air from the empty space of the jar so that there is a vacuum in the finished canned food. This is achieved by a high packaging temperature of the product or air is removed from the can during capping. The process of sealing cans is called seaming. Seaming is carried out on a vacuum - capping or conventional machines.

Sterilization of canned food

Most important process canning production is heat sterilization. The main goal of heat sterilization is to make the product resistant to spoilage by microorganisms, to ensure its long-term storage and good quality.

At the same time, during sterilization, it is necessary to ensure that a quality product is obtained in terms of taste, color, consistency and other indicators.

The sterilization mode (temperature, duration of the process, pressure) is developed in accordance with a specific methodology, taking into account a number of factors:

a) heat resistance of microorganisms causing spoilage of this product. Yeasts and molds, as well as many types of bacteria that do not form spores, die when heated to a temperature of 100 ° C. Spore-forming bacteria die during prolonged heating at a temperature of 110 - 120 ° C;

b) the type of product being preserved. The resistance of microbes to high temperatures is different and depends on the product. Products with high acidity are easier to sterilize. It is more difficult to sterilize low-acid products, canned food with great content squirrel;

c) the consistency of the product. Puree-like canned food thick consistency warm up slowly

d) sizes and shapes of cans. For sterilization big jars more time is needed;

e) container materials and can wall thickness. Tin cans warm up faster than glass ones;

e) packaging temperature of the product. At high temperature the product warms up to the sterilization temperature faster.

Backpressure is created in the strainer with the help of water or air in order to compensate for the pressure that develops in the jar when the product is heated and to prevent leakage (rupture of the lids).

The sterilization mode is indicated for each type of canned food and containers in which canned food is packaged. Canned food is sterilized in batch pressure autoclaves or continuous sterilizers. Canned food in glass containers is sterilized in water.

Canned food in tins can be sterilized with steam and water.

The batch autoclave is a vertical or horizontal cylinder made of thick steel sheet with a hermetically sealed lid. The autoclave has a bubbler through which steam is supplied. A thermometer and a manometer are installed to control temperature and pressure.

Canned food in cans is loaded into metal meshes and lowered into the autoclave using an electric hoist. The autoclave is preliminarily filled with water, the temperature of which should be 10–20 °C higher than the temperature of the contents of the jars. When sterilizing canned food in cans, water in an autoclave is heated almost to a boil. The lid is closed, steam is turned on and the water in the autoclave is heated to the sterilization temperature.

The desired sterilization temperature is maintained over time by adjusting the steam supply. Back pressure is created by supplying water or air and maintained at a predetermined level.

At the end of the holding time of the cans at this temperature, the steam supply is stopped and the canned food is cooled. After sterilization, jars with products are unloaded from the autoclave and subjected to further processing: they are washed in special machines, dried, the rim of the lid is varnished and labeled.

The products prepared in this way are placed in boxes or containers and sent for storage. Certain types of products (juices, jam, jam, marmalade) can be immediately shipped to the consumer.

Other types of products are usually kept in stock for 10 to 14 days until microbiological results are available. Products such as compotes, marinades are kept in a warehouse for two weeks in order to undergo diffusion processes and canned food acquire the necessary organoleptic qualities.

Canning fruits, vegetables and berries in the photo

When starting a vegetable or fruit preservation, it is necessary, first of all, to observe impeccable cleanliness, both of the raw materials themselves, and of the premises and the necessary equipment.

The technology of home canning must be strictly maintained without any violations and indulgences. This requirement is dictated primarily by security considerations.

In addition, it is a shame if some part of the product is simply spoiled due to non-compliance with the technology.

The use of certain spices, the ratio of sugar and salt, etc., gives great scope for creativity to any hostess - here each one relies on her own tastes and imagination.

The technology of preserving fruits and vegetables includes such preparatory work such as sorting raw materials, washing, cleaning, cutting, blanching, etc. Moreover, all of them must be carried out with high quality, because many failures, such as bombing, occur precisely because of errors in the preparatory work.

So, we preserve vegetables, fruits, berries at home.

Preparation of raw materials for canning: sorting

There is no doubt that for the preservation of vegetables and fruits for the winter, only high-quality fruits should be taken. From overripe, broken, rotten or frozen raw materials to make good workpiece impossible. Therefore, first of all, everything that you have collected or bought on the market must be sorted according to two indicators - quality and size.

In the first case, in preparation for canning, it is necessary to remove all vegetables or fruits that are unsuitable for processing. Please note that even a small amount of rotten fruits can greatly impair the taste of the finished product. The size is important because when salting or pickling, the products are of higher quality if all the fruits are approximately the same. This also plays a role during drying, since the entire batch will be ready at 1 time without overdried or underdried fruits.

In addition, I would like to draw your attention to the fact that processing should begin as soon as possible after harvest, since in hot weather, biochemical and microbiological processes in plant products proceed quite quickly, and they are directly related to the loss of nutrients. Thus, the faster you process vegetables and fruits, the more nutrients they retain. This is especially true of berries, as they are more tender. It is desirable that their storage time in a refrigerator does not exceed 1-2 days.

Washing fruits, vegetables and berries before conservation

Thorough washing is a necessary condition for high-quality preservation. On the outer shell of unwashed vegetables, fruits and berries are great amount microorganisms, as well as sand, soil particles, etc., and such an “additive” is unlikely to benefit your preservation. In addition, during the growth of plants, they can be repeatedly treated with pesticides.

When preparing raw materials for canning, it is better to wash plant products running water. When washing root crops, especially those collected in rainy weather, sometimes you need to first soak them for a while, and only then properly clean them with a brush for washing vegetables, and then be sure to rinse them with running water.

According to the rules of canning, you need to wash even tender berries raspberries or garden strawberries, especially if they are bought on the market. It is best to do this in a colander under the shower, watering the fruits for 1-2 minutes and shaking them slightly.

After washing, let the water drain and dry the product.

Cleaning and grinding fruits and berries before canning

Processing before canning fruits and vegetables includes mandatory cleaning. This process consists in the release of fruits from inedible parts, such as stalks, seeds, etc. Since peeled vegetables evaporate moisture faster, this work must be done quickly enough.

All root crops, cabbage, onions and garlic are subject to mandatory cleaning. When cleaning cabbage, green leaves and part of the stalk protruding above the head of cabbage are removed from it.

Then it is cut in half and the rest of the stalk is removed. It is very important to make sure that the cabbage is not attacked by caterpillars, which mostly hide under the outer leaves, so be careful.

When preserving stone fruits (cherries, plums, apricots) at home, it is better to remove the stones, as this will extend the shelf life of the finished product.

Apples, pears and quince, which begin to oxidize when cleaned in air, should be immediately immersed in salted (10-20 g of table salt per 1 liter) or acidified (5-10 g of citric acid per 1 liter) water.

The degree of grinding depends on how the processed products will be used. So, for example, when preparing soups for dressing dried vegetables they need to be crushed in the form of chips. Apples or pears for compotes are cut into identical slices, and they are rubbed through a sieve to get mashed potatoes.

You can wipe both cold foods, such as berries for cold jams, and pre-boiled ( pumpkin puree). In the first case, the raw material is oxidized due to its interaction with air, which is why it is so important, firstly, to carry out this work quickly, and secondly, to add sugar, which acts as a preservative.

Canning vegetables fruits berries: blanching

Blanching is recommended before canning fruits and vegetables. This very important operation allows, firstly, to preserve the natural color of vegetables and fruits, secondly, to put them more tightly in jars, and thirdly, it contributes to a better preservation of canned products. The fact is that short-term heat treatment displaces air from the fruit, which is completely unnecessary in the jar, since, gathering under its lid, it puts pressure on it, which can lead to bombing.

In addition, blanching inhibits the activity of enzymes, which significantly blocks biochemical processes that reduce the quality of preservation, as well as the activity of microorganisms found on vegetables and fruits.

Of course, this procedure leads to some loss of soluble nutrients, but to avoid this, you need to blanch the products with steam or in microwave oven. So, for steam blanching, you need large saucepan, into which another could be inserted, having a mesh bottom and a tight-fitting lid. Steamed products keep 2-3 minutes longer than in water.

For blanching in the microwave, put 500 g of vegetables in a container, add 0.5 cups of water, cover with a lid and keep at a maximum temperature for 7 minutes, taking it out in the middle of the term to mix the contents.

The blanching process for proper preservation consists in heat treatment, and this can be either short-term cooking or scalding with boiling water. Usually, harder vegetables (carrots, beets) are boiled, but spinach or chard can simply be poured with boiling water. Before preserving vegetables and fruits for the winter, the heat treatment time depends not only on the density of the product, but also on its size. Please note that the blanching time is counted from the start of boiling water with the product lowered into it.

For convenience, the main indicators of the blanching time for vegetables are given in the table below.

Blanching time before home preservation vegetables:

No. p / p	Product name	Product cutting	Blanching time, min
1	eggplant	pieces	3
2	Kohlrabi	whole	3
		pieces	1
3	Carrot	small whole root vegetables	5
		pieces	2
4	Beet	small whole root vegetables	5
		pieces	2
5	Bulb onions	rings	0,2
6	Leek	rings	1
7	Green pea	peas	2
8	Zucchini	pieces	2
9	Broccoli		3
10	Cauliflower	inflorescences no larger than 3 cm	4

It is more convenient to blanch vegetables in a wire basket, which is immersed in a pot of boiling water. Since the temperature of the water at this point is decreasing, you need to increase the degree of heating. You can also use gauze by sewing a bag out of it.

Before canning fruits and vegetables at home, it is better to blanch them in small portions, no more than 0.5 kg. So the product warms up faster and does not lose its attractive appearance. Moreover, water must be taken 10 times more than the volume of the product, and added as it evaporates.

So that blanched products do not change colors, immediately after scalding or boiling, they must be dipped in a very cold water, so at the same time prepare 1 more pot of water with ice cubes added. Cold water will stop the cooking process.

Then more warm product take out and dry on a clean linen napkin, which will absorb excess moisture.

Citric acid is added to the water so that light-colored vegetables, such as cauliflower, do not darken during blanching.

Proper preservation: frying, sautéing and stewing

These types of processing are used for the preparation of various canned snacks and vegetable preparations.

Frying in oil thickens the product, because it evaporates moisture from it, stops the activity of microorganisms and enzymes, and also gives it pleasant taste and aroma. This process must be carried out at a sufficiently high oil temperature so that the resulting breakdown of carbohydrates, the so-called caramelization, forms on the fruits golden crust. Usually fried onion, carrots, eggplant and zucchini. Roasting time depends both on the size of the pieces and on the firmness of the fruit itself and usually lasts from about 3 to 20 minutes.

The frying process is as follows: a frying pan with oil is heated over medium heat until it is hot. This will tell you the appearance of white smoke from pronounced odor vegetable oil. Prepared foods are loaded into the pan and the fire is strong as the temperature of the oil drops. Roasting is carried out with constant stirring, avoiding burning, otherwise the product will be spoiled.

Sauteing is a heat treatment during which the product is heated in a frying pan with a small amount of fat. Carrots, beets, onions, etc. are usually sautéed. For even heating, vegetables are cut into pieces and kept on low heat, stirring occasionally. Essential oils from the product pass into oil and give conservation pleasant aroma.

Stewing is a process of preparing food for preservation, in which fats are not used, but prepared vegetables are heated in own juice on low fire. Why they are laid in 1 layer, tightly close the pan with a lid, adding a small amount of water beforehand so that they do not burn. Stew, as a rule, tomatoes, zucchini, cabbage, eggplant, etc.

How to preserve fruits and vegetables for the winter: pasteurization and hot filling

Fruits, berries or vegetables prepared for canning are laid out in sterile jars and poured with syrup, marinade or brine so that at least 1.5 cm remains to the top of the neck. In this case, the fruits should be laid as tightly as possible, trying in no case to damage them.

In the process of preserving vegetables or fruits or berries, heat treatment can be carried out in several ways.

Pasteurization. This is how vegetables or fruits are preserved with high content organic acids. The temperature of the water in which pasteurization is carried out must be in the range from 70 to 95 ° C.

The process of pasteurization during canning takes place as follows: the jars filled with products are hermetically sealed and placed in a saucepan with warm water on a wooden grid. Having brought the temperature of the water to the required level, they note the time and reduce the fire so that it does not boil, but only is within the required limits. Pasteurization continues from 10 minutes to 1 hour, depending on the volume of the jar.

Hot pour. When preserving fruits and berries for the manufacture of juices, sauces, purees and caviar, the hot filling method is used. The prepared products are poured into jars while still boiling and corked. Then they are turned upside down and left to cool completely. So that the jars do not burst when pouring a boiling product, they must be heated.

Sometimes whole vegetables and fruits, such as tomatoes or cucumbers, as well as fruit and berry compotes, are preserved in this way. In the process of preserving fruits or vegetables, a 3-fold filling is used, that is, filled jars are poured twice with boiling water, which is kept for 5-7 minutes and drained. The third time, boiling syrup or marinade is poured into jars and hermetically sealed. Then they are placed upside down and covered with something warm so that the canned food cools longer, while undergoing additional sterilization.

If you did everything right during canning, then during the long winter the reward for your labors will be delicious preparations and appreciation of relatives; however, it happens differently. All flaws in the work appear, as a rule, in the 1st week. First, chains of gas bubbles appear, the lid swells, and then breaks off the can.

Sterilization of vegetables and fruits during preservation at home for the winter (with photo)

The sterilization process during preservation at home takes place at a temperature of 100 ° C and above. Sterilization is usually carried out in large saucepan, pouring water so that it covers the shoulders of the cans about 1.5-2 cm below the neck. A wooden grate must be placed at the bottom of the pan, which will protect the jars from breaking. For the same reasons, jars filled with hot products are not placed in a pot with cold water, and vice versa, i.e., the temperature difference between the water in the pan and the contents of the jar should not exceed 10-20 ° C.

Sometimes housewives, not having a wooden grate, put various rags on the bottom of the pan. This is wrong, because in this case it will be difficult to determine the beginning of boiling water, and after all, the sterilization time is counted from this very moment; if you do not warm up the product long enough, it may deteriorate.

Please note that heating the water in the pan before it begins to boil must occur quickly so that the canned product is not digested and does not turn into porridge. So, to reduce this time to a minimum, fulfill 2 conditions:

• cover the pot with jars with a lid;
• the temperature of the preserved products should initially be high.

Moreover, at the time that is allotted for sterilization, boiling should not be violent.

The duration of the sterilization process is usually indicated in the recipe and depends mainly on the acidity and density of the preserved mass. Yes, on average liquid products sterilize for 10-15 minutes, thick - up to 2 hours or more, more sour foods require less time than non-acidic, because in acidic environment bacteria do not develop. This time also depends on the volume of jars: naturally, the larger the volume, the longer the sterilization time.

After sterilization is completed, the jars are carefully removed from the pan and immediately sealed, checking the quality of the seaming.

The process of preserving fruits and vegetables for the winter is shown in the photo below:

STEP #1
STEP #2

STEP #3
STEP #4

STEP #5
STEP #6

STEP #7
STEP #8

STEP #9
STEP #10

What you need to preserve fruits and vegetables at home

The use of spices gives the preservation taste and aroma, and all of them can be divided into 2 categories. The former serve for preservation (salt, sugar, pepper, vinegar or lemon acid, but in no case acetylsalicylic acid or aspirin), and the latter - for flavoring (cloves, cinnamon, spices). However, the main requirement for both the 1st and 2nd groups is the same - spices should be in moderation.

Salt is perhaps the most ancient spice. For canning, it is better to use medium grinding rock salt. iodized or sea ​​salt it is undesirable to take, since, firstly, they are more expensive, and secondly, they somewhat change the taste of the product.

Other indispensable ingredient when preserving, vinegar is considered - a product obtained either by natural souring grape wines, or artificial fermentation of alcohols and carbohydrates using acetic acid bacteria. Thus, vinegar can be made from any product containing carbohydrates, i.e. from fruits, berries, grains, and even wood.

Citric acid is more often used in fruit preparations. She represents small crystals white color, which are obtained both from lemon juice and synthetically.

Pepper is also an ancient and very common spice. Mainly used in home preparations allspice peas, which gives a pleasant aroma, but less pungent than black and red varieties.

Used for conservation aromatic additives from various parts spice plants- leaves, bark, pods, flowers and even flower stigmas.

Bay leaf gives canned food a specific smell, but it should not be added in large quantities, as the finished product can become bitter.

Many herbs (dill, parsley, basil, mint, etc.) can be taken both fresh and dried. Often used for blanks and spicy vegetables: garlic, horseradish, celery, onion, etc. In addition, to flavor brines, housewives often add leaves of local plants - cherry, currant, raspberry, and sometimes oak bark is used to strengthen vegetables.

And what is needed for canning fruits and berries? In fruit and berry preservation, cinnamon is often used, nutmeg, vanillin, as well as herbs such as mint or lemon balm. Although many spices can be used for both sweet and vegetable preparations. Such universal seasonings are cloves, ginger, anise, etc.

Fumigation when drying fruits and vegetables

This process is mainly used for drying fruits and vegetables. Due to fumigation with sulfur, or rather, with sulfur dioxide, the fruits do not darken and even when dried, retain their color. natural product. Usually fumigated whole fruits with hard pulp: apples, pears, apricots, plums, etc.

Since sulfur dioxide is very toxic, fumigation is carried out in separate non-residential premises. The fruits intended for this are laid out on sieves or sieves, on which they will subsequently begin to dry.

The consumption of sulfur depends on the volume of production, while using the ratio: 100 kg of product - 200 g of sulfur. It is placed on the braziers with charcoal, which are installed indoors, observing the rules of fire safety, and set on fire. In this case, you need to work in a gas mask. In addition to sulfur, liquid sulfur dioxide in cylinders can also be used.

The holding time of fruits in a gaseous environment depends primarily on their density and size. So, for example, apples, pears and quince are recommended to be processed for at least 16-18 hours, cherries and plums - about 15-16 hours, but more delicate berries - apricots or garden strawberries - only 5-10 hours.

Dried fruits are absolutely harmless to humans, since they contain a negligible amount of sulfur dioxide.

Content

Introduction…………………………………………………………………………….4
1 Market of canned vegetables and fruits………………………………..6
2 History of canning……………………………………………………..6
3 Principles for the classification of conservation methods food products……..8
4 Preparing for canning………………………………………………….9
4.1 Washing ………………………………………………………………………9
4.2 Sorting and cleaning…………………………………………………...9
4.3 Grinding and rubbing…………………………………………….10
4.4 Blanching …………………………………………………………… 10
5 Preservation methods ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….
5.1 Fermentation…………………………………………………………………...11
5.2 Salting…………………………………………………………………..12
5.3Drying……………………………………………………………………..12
5.4 Thickening………………………………………………………………...13
5.5 High temperature preservation……………..13
5.5.1 Sterilization of products…………………………………………..13
5.5.2 Pasteurization………………………………………………………..14
5.6 Refrigeration and freezing…………………………………………. .14
5.7 Boiling fruits with sugar………………………………………………….14
5.8 Sugar-free processing of fruits and berries………………………………..15
5.9Preservation by reducing the temperature…………………………….16
5.9.1 Cooling…………………………………………………………….16
5.9.2 Freezing………………………………………………………16
5.10 Chemical methods of food preservation…………………..17
5.10.1 Preservation with ethyl alcohol …………………………………………………………………………………17
5.10.2 Marinating………………………………………………………….17
5.11 Preservation with acids (antiseptics)…………………………17
5.12 Preservation with antibiotics……………………………………..18
5.13 Canning with gases………………………………………………….18
5.14 Preservation by biological treatment of the medium………………...19
5.14.1 Lactic acid fermentation………………………………………………19
5.14.2 Alcoholic fermentation……………………………………………….20
5.14.3 Acetic fermentation…………………………………………………21
5.15 Preservation by reducing humidity……………………………..21
Conclusion……………………………………………………………………………22
Electronic publications on the Internet……………………………………………….. 24

Introduction

Utility fresh vegetables and fruit has always been known to man, and people have long learned to grow and preserve them perfectly.
Canned fruits and vegetables are fruits and vegetables that have been processed at high temperature or cold to protect them from microbiological spoilage, which is caused by bacteria, molds and yeasts that develop under certain conditions (the presence of moisture, heat, etc.). If microbes are deprived of such conditions, they will not be able to develop. It is on this principle that all known methods of preserving food are based.
Home canning is advisable, first of all, when vegetables and fruits are grown on their own plot or collected in the forest, in the fields. At home canning you can prepare a product with a special composition, unusual taste, dietary, etc.
During the growth period, while the fruit is associated with the mother plant, the risk of infection of its internal tissues with microbes is small. This is largely prevented by the intact outer shell - the skin. In addition, during growth and development, fruits and vegetables are characterized by increased resistance to diseases.
Mechanical damage to the skin during harvesting facilitates the penetration of microorganisms to the internal tissues. After harvesting, fruits and vegetables enter new environmental conditions, which entails a change in vital processes and a decrease in resistance to fungal and bacterial diseases. This is also facilitated by changes occurring during storage in the water regime of tissues.
The plucked fruit remains alive, the previous processes continue in it, but without the influx of substances from the plant. Therefore, vitamins, sugar and other important substances decrease in the harvested fruits due to respiration. The decrease in the amount of these substances occurs the faster, the higher the storage temperature of the fruit. At the same time, the fruit becomes softer, its color, taste, and aroma deteriorate.
Only a few cultivated and wild-growing fruits and berries can be stored fresh for a long time: nuts, winter and late winter varieties of apples and pears, citrus fruits, quince, chokeberry, some types and varieties of mountain ash, and late-ripening berries: common viburnum, barberry, cranberries, lingonberries. Basically the same ripe fruit and berries belong to perishable products nutrition. Their deterioration is due to the action of enzymes and microorganisms.
Enzymes are substances found in plant cells in very small quantities. They are catalysts for all biochemical processes in fruits and berries, under certain conditions they can adversely affect them. It has been established that low temperatures contribute to a significant decrease in the biological activity of enzymes, and at temperatures above 60°C they, as a rule, are destroyed.
The second main reason for the spoilage of fruits and berries is the impact on them of various microorganisms (bacteria, fungi), which most actively develop at a temperature of 20-40 ° C. Cooling vegetables and fruits to 0°C and below greatly inhibits the vital activity of microorganisms, and when heated to 70-90°C and especially above 100-122°C, most of them die (spores of microorganisms die at 180°C). The use of certain concentrations of salts and acids also reduces the activity of harmful microflora.
The problem of year-round consumption of vegetables and berries can be solved by a rational method of their processing. When canning perishable fruits and vegetables long time saved without degrading quality.

1 Market of canned vegetables and fruits

Fruits and vegetables are an integral part of human nutrition, especially due to the content of minerals in them, which are necessary for the normal physiological course of life processes in the body. However, the seasonality of the collection of vegetables and fruits, the difficulties in storing many varieties of fruits and vegetables forced people to look for new forms of food processing, which would significantly extend their shelf life for consumption and ensure their safety (trademark, the presence of essential minerals, etc.) during the off-season. Old forms of canning that have been used by humans for a long time include drying, smoking, and boiling with large amounts of sugar added. The beginning of the introduction of modern methods of preservation, which are based on sterilization at high temperatures, can be considered 1795, that is, the period of the Napoleonic campaigns, when french army experienced great difficulties in providing food. It was then that a reward of 12 thousand francs was awarded for the development of a method for reliably preserving the nutritional properties of products. The prize was awarded to the Frenchman Appert, a skilled chef, and later a prominent industrialist, supplier of sweets, sweets, jams, who became known (in world literature) as the inventor of a method of preserving food by canning. At first, his invention was used exclusively for the needs of the army, but soon found wide application in everyday life in the manufacture of canned food.
Thanks to this invention, canned vegetables and fruits appear on our table, both beloved by everyone at home and produced by foreign enterprises.

2 History of canning

In 1795, the French chef Nicolas François Appert won a competition for The best way long-term storage of products. He was awarded the honorary title "Benefactor of Humanity" and was awarded a gold medal. The cook filled the jars with meat, broth and jam, sealed them and boiled them for a long time. Eight months later, the contents of the jars were of excellent quality. Since then, canning has turned from a miracle into an ordinary concept. With the help of simple techniques - heating (pasteurization) or boiling (sterilization) - microorganisms (molds, microbes) and enzymes (substances that accelerate chemical reactions and biological processes) are destroyed, and the nutritional value and taste qualities stay! Doesn't compare to fresh produce, but still...
The word "conservation" comes from the Latin word conserve, which means "preservation". The scientific foundations of modern preservation methods were given back in the 19th century, when, in addition to the visible culprits of food decomposition, such as mold and fungi, invisible forms of microorganisms, bacteria and yeast fungi, were also discovered. This discovery was made by the famous French chemist Louis Pasteur (1822 - 1895), who studied in detail, first of all, yeast and pathogenic microbes and at the same time laid the scientific basis for killing their embryos. In honor of him, pasteurization was named a method of partial sterilization of substances at elevated temperatures, primarily liquid ones. Pasteur had predecessors in the specialty of practical food preservation, they were the Parisian chef Nicholas Appert (died 1840). In 1804, he tried to preserve food in cans by boiling and described and showed his method in Paris in 1810 (L`art de conserver toutes les substances animalses et vegetales, Paris 1810, the first German edition was published in Prague in 1844). tin can filled with products intended for canning, heated with steam or in hot water. Excess air escaped through a small hole at the top of the jar, and this hole was sealed in the field of its exit. The hermetically filled jar was then boiled in hot water, at the same time, so that the temperature could rise to 135 degrees, various salts were added and thereby the required degree of sterilization was achieved. Further evolution brought not only knowledge of the causes of decomposition, but also further biochemical changes, explained the significance of food metabolism (metabolism), both the starting materials and the needs of human metabolism, for which there are enough basic nutrients such as saccharides, lipids and proteins and biocatalysts, primarily vitamins, enzymes, growth substances, pigments and antibiotics. This enabled the scientific specialty of food preservation, which in a rational way provides long-term storage of difficult-to-preserve products, especially fruits and vegetables, for year-round consumption and in a form that best preserves their original appearance.
From this outline follows the importance of conservation, its social, state and hygienic significance, both from the point of view of the producer and the consumer.

3 Principles for classifying food preservation methods

Various methods of food preservation according to the classification proposed by Ya. Ya. Nikitinsky are based on the following principles:
1) maintenance of life processes occurring in raw materials and preventing the development of microorganisms (principle of biosis); on this principle is based, for example, the storage of fresh fruits and vegetables;
2) suppression of the vital activity of microorganisms by the influence of various physical or chemical factors (the principle of suspended animation); at the same time, life processes occurring in the raw material are also suppressed. The principle of anabiosis is based on the storage of food products at low temperatures or in an atmosphere of carbon dioxide, conservation by increasing the concentration of substances dissolved in the product, as well as by adding chemical preservatives that retard the development of microorganisms (for example, acetic acid when marinating);
3) the cessation of the vital activity of microorganisms, accompanied by the cessation of vital processes in the raw material (the principle of abiosis), - preservation by heating, the action of electric current, ionizing radiation, ultrasound, the addition of chemicals that are toxic to microorganisms, as well as the mechanical removal of microorganisms from the product (sterilizing filtration).
At the same time, none of these principles underlying the classification can be implemented in practice in its pure form. Most often, these or those methods of preservation are based on mixed principles.

4 Preparing for canning

Considerable attention in the canning process is paid to the quality of raw materials used for the production of canned vegetables and fruits, because not only the quality of the finished product depends on this, but also the level of mechanization of production and labor productivity, because machines cannot efficiently process raw materials of various shapes, sizes and grades. With all canning methods, food products are usually pre-treated first - washing, sorting, cleaning from inedible or inedible parts (which increases the nutritional value of products compared to the original), grinding and blanching (if necessary), as well as the actual canning (under the influence of high temperature - pasteurization or sterilization; under the influence of low temperature - fermentation and soaking, salting, pickling, canning with sugar, dehydration).

4.1 Washing

Thorough washing is a necessary condition for the processing of fruits, berries and vegetables. It allows you to remove earth, sand and, most importantly, microorganisms that are on the surface of fruits, berries and vegetables, which are the main cause of food spoilage. In addition, it is possible that fruits and vegetables were sprayed with various pesticides in the fight against plant diseases and pests. Washed fruits and vegetables should be immediately cleaned, chopped and put into further processing.

4.2 Sorting and cleaning

The purpose of sorting is to remove rotten, mechanically damaged, overripe, unripe fruits and vegetables. Healthy, ripe fruits and vegetables of the same size are selected, divided into large and small. After sorting, wash again in the shower. Some berries (strawberries, raspberries, etc.) in nets are immersed several times in water for 0.5-1 minutes, changing it to clean. Then cleaning is done. The purpose of cleaning is to remove the inedible or inedible part from fruits and vegetables. Preliminary cleaning of root crops consists in cutting off the upper green parts with hard, tasteless tissues, thin lower and side roots. Wash very thoroughly with water. Onions, garlic are peeled, cutting off the upper and lower parts and removing the scales. Bones are removed from cherries or sweet cherries. Then you need to remove the rotten parts of the fruit and wash them again. Green peas must be peeled (separate the grain from the wings). Considering that some peeled vegetables and fruits darken quickly in the air, they cannot be left unfilled with water.

4.3 Grinding and rubbing

Use different methods of chopping vegetables and fruits, depending on the purpose for which they will be used. Root crops are crushed in the form of shavings or slices (onion slices, cabbage is chopped or chopped). To obtain juice, juicers, etc. are used.

4.4 Blanching

Blanching (from the French word blanshire - whiten, bleach) is one of the most important operations in preparing fruits and vegetables for processing. It consists in the fact that vegetables or fruits are scalded with boiling water or boiled for several minutes in water or in a saline solution with the addition of citric acid. Some vegetables are blanched to fully prepared(beets, carrots), that is, they are simply boiled. The quality of the product and the amount of losses largely depend on how correctly blanching is carried out. When blanching, the natural color of vegetables and fruits is preserved, they fit more tightly into jars, do not crack in a jar when poured with hot syrup or marinade, the safety of canned food increases, etc. The blanching time must be strictly observed, since the fruits overexposed in boiling water quickly boil soft, their taste deteriorates, and the underexposed subsequently darken. The duration of blanching depends on the type, size of the raw material and the purpose of its processing. After blanching, fruits or vegetables are cooled quickly by immersing them in clean, cold water. Some types of raw materials can be preserved without blanching. So, for example, compotes prepared without blanching fruit are much tastier.
5 Canning methods

Canned vegetables and fruits are not much inferior to fresh ones in terms of the content of vitamins, mineral salts, sugars. Therefore, it is worth trying to have tomatoes and eggplants, cucumbers and peppers, peaches and apricots, pears and strawberries on your table in winter and early spring.
There are many different methods of preservation. Almost all of them are based on the elimination of conditions for the vital activity of microorganisms - bacteria, molds, yeasts that cause food spoilage, as well as on the suppression of the activity of their own enzymes that can reduce the quality of the product. Canned food obtained in this way can be stored for a long time. Other methods are aimed at limiting the vital activity of microbes, which at the same time remain in the product, but their growth and development are delayed. High or low temperatures, preservatives (for example, vinegar), salt, sugar, dehydration prevent microbes from existing in clover. the following types canning: drying, salting and pickling, marinating, freezing, using high concentrations sugar syrup, sterilization and pasteurization.

5.1 Fermentation

We are talking about canning with acids contained in large quantities in fruits or obtained during the usual biological process - fermentation. These include citric, grape, malic and lactic acid. From a practical point of view, weak oxidation up to a concentration of 1.5% acids is most often used in the production of compote and vegetables in sour filling. Foods are also prepared during preservation by heating to a temperature of 100 0C, i.e. pasteurization. Further, sometimes combinations of lactic and acetic acids are used in a ratio of 2: 1 with a concentration of 2% when preserving by lactic fermentation.
In essence, only acetic acid gives canned products in tolerable taste concentrations, and then if in an amount of no more than 4-6%. At present, this method is almost never used.

5.2 Salting

The preservative effect of table salt (NaCl) is manifested at concentrations of at least 10%, some microorganisms tolerate concentrations up to 30%. In practice, lower salt concentrations are used in combination with pickling when preserving vegetables. Salt, as an independent preservative, is used only when preserving vegetables in salt. Sprinkle chopped and chopped vegetables with salt. Rub garlic with salt in the same way. Finished products should contain up to 20% salt and be stored in a cool, dry place.

5.3Drying

Drying is the reduction of water from food to a gaseous state. It is necessary to evaporate 80 - 90% of the initial water content. Drying can be carried out in the sun or in fresh air, in our climatic conditions in various drying devices. The drying process is influenced primarily by the temperature and air velocity in the dryer. At the beginning of drying, it is more profitable to maintain a high temperature and air speed, by the end of drying, the influence of air movement is practically absent. The amount of water vapor in the air matters for the drying speed. The higher the air temperature, the drier the air under these conditions, and it will take more water vapor when drying products. On the contrary, excessively high temperature and low humidity of the exhaust air reduces the efficiency of the system. During drying, there are always changes in the organoleptic and biochemical properties of the product. Drying is an irreversible process; it is impossible to return products in their original form by adding water back. Swelling capacity is one of the indicators of drying quality. In addition to a change in color - browning - during drying, a change in taste also occurs. In the future, there is a decrease in the content of vitamins. Therefore, it is advantageous for some products, mainly divisible vegetables, to be slightly boiled before drying and thereby reduce the activity of the enzymes present.

5.4 Thickening

Thickening is the partial evaporation of water from foods. Concentration of insoluble substances of products creates an environment unsuitable for the vegetation of microorganisms. Fruit concentrates usually contain 50-70% dry matter, vegetable concentrates - 25-50% dry matter. At low concentrations, further preservation should be applied, for example, pickling, candied, if necessary, sterilization. Raw materials during thickening are first squeezed or rubbed. To preserve the organoleptic (taste, smell, color) and biological (vitamins) properties, it is more profitable to thicken it at low temperatures, mainly by reducing the pressure in autoclaves, and as quickly as possible. In the household, direct heating to a temperature close to boiling is usually practiced. At such temperatures, there is a high antimicrobial effect, which leads to practical pasteurization. On the contrary, coloring undergoes great changes. Fruit and vegetable purees must be stirred during thickening so that they do not burn.

5.5 High temperature preservation

High temperature preservation is the most effective method, based on the destruction of the majority of microbes and the elimination of the possible subsequent entry of microbes into products. There are 2 options for canning using high temperature. Sterilization is carried out at a temperature of 100 degrees Celsius, and pasteurization at a temperature of up to 100 degrees Celsius.

5.5.1 Sterilization of products

Prepared (preferably hot) fruits or vegetables are placed in a glass container, poured with hot sugar syrup, marinade or tomato sauce, covered with boiled tin lids and placed in a sterilizer with hot water. The temperature of the water in the sterilizer should be 15-20 degrees higher than the temperature inside the glass container, and the water level in it should be no more than 3 cm below the upper edge of the jar. The sterilization time is counted from the moment the water boils in the sterilizer. The sterilization time varies from product to product and is usually specified in the recipe. After sterilization, the jar is carefully removed, placed on the table and immediately rolled up using a typewriter. Jars with a glass lid and a clamp are closed with a clamp immediately, before they are set to be sterilized.
Between the banks and the wall of the container in which the treatment is carried out, there must be a gap of at least 5-10 mm. During sterilization, water should not be allowed to boil violently.

5.5.2 Pasteurization

Some fruits and berries boil during sterilization, their taste decreases, therefore, for canning apricots, grapes, small tomatoes, etc. better to use pasteurization. Canned food that is packed hot and immediately hermetically sealed should be turned upside down and cooled. This type of preservation is called self-sterilization.

5.6 Refrigeration and freezing

The essence of this method of preservation is that at low temperatures the vital activity of microorganisms is suppressed, the activity of enzymes decreases, and the course of biochemical reactions slows down. At the lower temperatures characteristic of refrigeration, fruits and vegetables continue to undergo, albeit slowly, respiration processes that allow them to remain fresh for several weeks and even months.

5.7 Cooking fruits with sugar

When boiling fruits with a large amount of sugar (approximately 1 part of fruit per 1 part of sugar), a product with a high sugar concentration of 60-65% or more (jam, jam, marmalade, jelly, etc.) is obtained, which does not allow microbes to develop. As emphasized by S.S. Atatyan, when canning at home, you should remember following rules: use fresh fruits and vegetables; store healthy, peeled and chopped fruits, berries and vegetables for no more than 30 minutes before placing them in jars for blanching or boiling; use dishes made of ceramics, glass, of stainless steel, as well as enameled without cracks; blanching and cooking of fruits and vegetables should be carried out with the obligatory consideration of their degree of maturity; strictly adhere to the modes of heat treatment, especially sterilization; prolonged heat treatment with access to oxygen reduces the content of vitamins in food. Subject to sanitary rules and technological regimes, processed fruits, vegetables and berries can be stored for up to 2 years. Depending on what is supposed to be prepared from fruits and vegetables, they are processed accordingly after washing.

5.8 Sugar-free processing of fruits and berries

There are several ways of "sugar-free" processing of fruits and berries. As you know, sugar is put in berry compotes and juices not only for sweetness, but also because of its preservative properties. So, a workpiece with 60 percent sugar will not ferment even in an open jar at room temperature.
etc.................

Publisher: Agropromizdat

The year of publishing: 1992

Language: Russian

Pages: 352

Introduction

Section I. General Conservation Issues

Chapter 1. Principles and methods of preserving fruits and vegetables

First of all, it is impossible to store raw materials in the open air or in such a shelter where direct Sun rays or the roof and walls of which easily pass heat. It must be borne in mind that the intensity of the biochemical process of respiration mentioned above, as well as the rate of all chemical reactions, increases greatly with increasing temperature. When heated, the evaporation of moisture from the surface of the fruit increases, which leads to weight loss and reduces the physiological stability of the raw material. Therefore, it is best to store raw materials on a site adjacent to the workshop, covered from above with a canopy of a material that does not conduct heat well and is open on three sides.

Depending on the type of raw materials, the fruits are stored in wooden boxes, box pallets, containers, in bulk. At the same time, it is advisable not to lay the raw materials (especially in bulk) in a very high layer, otherwise air access to individual fruits will be difficult. In this case, the process of normal (aerobic) respiration will be disturbed and the so-called intramolecular or anaerobic respiration will occur, proceeding according to the above scheme. alcoholic fermentation and leading to spoilage of raw materials. Therefore, raw materials, especially those of delicate consistency, are stacked in cages in stacks up to 2 m high, leaving passages between individual stacks. With such storage, there is sufficient air access, and breathing proceeds normally.

Chapter 2. Preparatory technological processes food preservation

Depending on local conditions and the remoteness of the raw material zone, road, rail and water transport is used to transport raw materials to the plant.

Fruits and vegetables are usually transported in box pallets - containers that can hold 350-400 kg of raw materials. Pallets are removed from vehicles using forklift trucks. Raw materials that have a solid consistency and are resistant to mechanical stress can also be transported in bulk in vehicles (onions, root crops, apples).

Chapter 3

Tin containers are light, their mass with equal volume is approximately 3 times less than the mass of glass containers. The mass of tin containers in relation to the mass of the product is only 10-17%, for glass containers this ratio is in the range of 35-50%.

Tin containers are only subjected to deformation during shocks, impacts, and falls, while glass containers are destroyed, sometimes even when the cans are opened.

Tin containers are insensitive to temperature changes, glass containers are not heat-resistant, which complicates the processes of its washing and subsequent thermal sterilization of canned food.

Chapter 4

Packed canned food by machine or manually. When packing, they monitor compliance with the components of canned food.

A lot of canned foods are one-component: liquid, puree and pasty, thick homogeneous masses, such as, for example, natural fruit juices, juices with pulp, pureed fruits, jam, tomato pastes and so on.

Many canned foods consist of two components: a solid part - fruits, vegetables, meat and a liquid part - syrup, brine, tomato sauce, broth. These include canned food such as compotes, marinades, green peas, natural beets, etc.

There are also multicomponent ones, in which the solid part is represented by several types of raw materials, for example, canned vegetable snacks such as stuffed pepper or eggplant containing the main raw material, minced carrot and tomato sauce.

Chapter 5. Sterilization and pasteurization of canned food

Sterilization is a general term for the heat treatment of canned food to kill microorganisms at all temperatures. In a narrower sense, sterilization is commonly understood as the heat treatment of canned food at temperatures above 100 °C. Sterilization, carried out at temperatures of 100 ° and below, is called pasteurization.

It should be noted that the task of heat sterilization is not to destroy all those in tin can microorganisms, but only those that can develop with normal conditions storage and at the same time cause damage to canned food or form products of their vital activity (toxins) hazardous to health. Some microorganisms, such as hay or potato stick, do not develop in canned food and are harmless in this sense. There is no point in trying to destroy them, especially since they are very heat-resistant.

Thus, in the process of sterilization, one should achieve not absolute, but only so-called industrial sterility, in which there should be no food spoilage agents or pathogenic (causing diseases) and toxigenic (causing poisoning) forms in canned food.

Chapter 6

Section II. Preservation of certain types of food products

Chapter 1. Preservation of vegetables and fruits by microbiological methods

Chapter 2. Marinating vegetables, fruits and berries

Chapter 3. Technology of natural canned vegetables

Chapter 4

Chapter 5

Chapter 6

Chapter 7. Concentration of tomato products

Chapter 8. Technology canned compotes and sterilized fruit puree

Chapter 9 Fruit Juice Technology

Chapter 10

Chapter 11

Chapter 12 fruit preparations with sugar

Chapter 13 Types of marriage of canned food

Chapter 14

Chapter 15

Chapter 16

Chapter 17

Chapter 18

Chapter 19

Section III. Technochemical product quality control

Chapter 1. Organization and tasks of technochemical control of production

Chapter 2. Determination of solids and density of solutions

Chapter 3. Determination of acidity

Chapter 4 Determination of fat content

Chapter 5

Chapter 6. Determination of foreign substances in food products

Chapter 7. Sanitary and microbiological control of canning production

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Home canning has always been popular in our country. And it's not just about the need to save fruits and vegetables for the winter in order to provide the family with food.

For many, home canning is a hobby that allows you to cook delicious food, and even with a long shelf life.

Almost any food can be preserved, but vegetables, fruits, and berries are most often used.

You can prepare food for the future in various ways - it all depends on your imagination, capabilities and desire to spend some time on it.

The main types of fresh food preservation are: drying, salting, pickling, marinating, canning with sugar and freezing.

Each method has its own advantages, and the finished product, depending on the type of canning, has its own specific taste.

Types of canning

Drying fresh vegetables, berries and fruits

Drying fresh vegetables, berries and fruits is one of the first known ways product preparations. You can dry the food in the air or in the oven.

Washed fruits are cut into pieces for air drying. thin slices or pieces and spread in a thin layer on a horizontal surface covered with several layers of gauze. Periodically, pieces of fruit or berries are stirred so that the moisture leaves evenly. Drying is carried out in a well-ventilated place without drafts during the hot season. To dry in the oven, the chopped raw materials are poured onto baking sheets, a low fire is turned on, and the oven door is left ajar. The raw materials are periodically mixed, the juice that stands out is removed from the pan. Dried vegetables, fruits and berries can be stored for a long time. All known dried fruits, dried wild rose, white roots are widely used in cooking.

Salting

Vegetables and gourds are ideal for salting. In addition to vegetables, you will need salt and sugar. Salt prevents the development of rotting bacteria and thus protects the product from spoilage. In addition, in the presence of table salt and sugar in a container with vegetables, fermentation occurs - lactic acid bacteria develop, which produce a preservative - lactic acid. The content of salt in pickled cucumbers is 3-5%, and acids - 0.6-1.2%.

fermentation

Fermentation also protects vegetables from rotting. For harvesting, the same preservatives are used as for salting, but in different proportions: in pickled vegetables contains less salt, so lactic acid bacteria and, accordingly, lactic acid is produced more. For example, in sauerkraut contains 1.5-2.5% common salt and 0.6-2% acid. However, salted vegetables have one advantage - they last longer in airtight containers.

Pickling

Preserving fresh vegetables with the addition of acetic acid is called pickling. It also uses table salt, spices and sugar in different proportions. Acetic acid is a preservative that prevents the development of bacteria in fruit containers and spoilage of the product. She attaches finished product spicy taste. Sometimes citric acid is used instead of acetic acid as a preservative. Pickled vegetables and fruits taste sweet and sour.

Canning with sugar

Sugar is used in many types of preservation, including salting, pickling, and pickling. But here we will focus on canning in sugar solutions of high concentration - syrup or pure sugar.

In this way, various jams, jams, marmalade, compotes, candied fruits, etc. are prepared. The concentration of sugar in jam should be at least 65%, in candied fruit sugar should be at least 75-80%. This is the only way fruit and berry raw materials can be stored for a long time. Foods canned with a lot of sugar have a sweet taste and a very long shelf life.

When canning with sugar, certain rules must be observed. For example, syrup is best prepared with the water in which the products were blanched.

Ready syrup must be clean, transparent. For those who suffer diabetes sweeteners (xylitol, sorbitol) are used in preservation.

In this case, it is also better to use unripe fruits, as they contain less sugar. To prepare the syrup, take 185 g of sorbitol or 250 g of xylitol per 1 liter of water.

To prepare a regular syrup, the amount of sugar can vary (10% - 100 g per 930 ml of water, 25% - 280 g per 830 ml of water and 40% - 470 g per 700 ml of water, 65% - 860 g per 460 l of water).

The readiness of the jam can be determined different ways. For example, jam is ready when the intensive formation of foam stops and the fruit mass begins to slowly boil with the same fire strength. If the jam is ready, then the foam is formed in the center of the boiling mass, and the berries in the syrup are evenly distributed. A drop of syrup ready jam when cooling does not blur on a saucer. If the jam is already ready, then the sugar syrup does not separate from the portion taken for the sample.

To determine the readiness of jam, you need to put a small portion on a saucer. If it does not spread, then it is ready.

Freezing

Freezing is a special kind of canning. It allows you to save all useful nutrients, including vitamins. Even the rapidly deteriorating vitamin C, which we so lack in winter, is preserved.

For freezing, vegetables and fruits are cut into cubes 2 X 2 cm or slices 0.5 cm thick and placed in plastic bags or plastic containers in small layers. At the same time, excess air must be removed from the bags - then the raw material will freeze evenly, the package will form less ice and it will be easier to defrost.

To defrost, the product can be poured with hot water or heated in a microwave oven. Can be defrosted and naturally- wait until vegetables or fruits thaw.