Technology of preservation of fruits and vegetables, assortment of canned fruits and vegetables. Abstract: "Canning products

Canning Basics

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 methods of food preparation. You can dry the food in the air or in the oven.

For drying in the air, the washed fruits are cut into 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. The well-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 table 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: pickled vegetables contain less salt, so lactic acid bacteria and, accordingly, lactic acid are produced more. For example, sauerkraut contains 1.5-2.5% 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. It gives the finished product a 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 suffering from diabetes, sweeteners (xylitol, sorbitol) are used in conservation.

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 liters of water).

The readiness of jam can be determined in 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 distributed evenly. A drop of syrup from ready-made jam does not spread on a saucer when cooling. 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 the 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 materials will freeze evenly, less ice will form in the package, and it will be easier to defrost.

To defrost, the product can be poured with hot water or heated in a microwave oven. You can also defrost in a natural way - wait until vegetables or fruits thaw.

Canning fruits, vegetables and berries in the photo

When starting 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 canning fruits and vegetables includes such preparatory work 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. It is impossible to make a good harvest from overripe, broken, rotten or frozen raw materials. 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 fruit 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 there are a huge number of 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 with running water. When washing root crops, especially harvested in rainy weather, it is sometimes necessary 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 canning rules, even tender raspberries or garden strawberries should be washed, 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 freeing the fruits from inedible parts, such as stalks, seeds, etc. Since peeled vegetables evaporate moisture faster, this work must be done fairly quickly.

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 dried vegetables for dressing soups, 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 products, such as berries for cold jams, and pre-boiled ones (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 food with steam or in the microwave. So, for steam blanching, you need a large pan into which you could insert another one that has 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 canned vegetables:

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 the volume of the product, and added as it evaporates.

To prevent blanched foods from changing colors, immediately after scalding or boiling them, they must be immersed in very cold water, so at the same time prepare 1 more pot of water to which ice cubes are added. Cold water will stop the cooking process.

Then the still warm product is taken out and dried 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, as it evaporates moisture from it, stops the activity of microorganisms and enzymes, and also gives it a 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 a golden crust on the fruits. Usually fried onions, 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 with a pronounced smell of 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 the preservation a pleasant aroma.

Stewing is the process of preparing food for preservation, in which fats are not used, but prepared vegetables are heated in their own juice over low heat. Why they are laid in 1 layer, tightly cover 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 with a high content of organic acids are preserved. 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 grate. 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 work will be delicious preparations and gratitude from loved ones; 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 a large saucepan, pouring water in such a way 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. So, on average, liquid products are sterilized within 10-15 minutes, thick ones - up to 2 hours or more, more acidic products require less time than non-acidic ones, since bacteria do not develop in an acidic environment. 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 citric acid, but in no case acetylsalicylic acid or aspirin), and the latter for flavoring (cloves, cinnamon, herbs). 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. It is undesirable to take iodized or sea salt, since, firstly, they are more expensive, and secondly, they somewhat change the taste of the product.

Another indispensable ingredient in canning is vinegar - a product obtained either by the natural souring of grape wines, or by the artificial fermentation of alcohols and carbohydrates with the help of 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. It is a small white crystals, which are obtained both from lemon juice and synthetically.

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

For preservation, aromatic additives are used from various parts of spicy 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, spicy vegetables are also used for preparations: garlic, horseradish, celery, onions, etc. In addition, the leaves of local plants - cherry, currant, raspberry - are often added to flavor the brines, and oak bark is sometimes put to strengthen the vegetables.

And what is needed for canning fruits and berries? In fruit and berry preservation, cinnamon, nutmeg, vanillin, as well as herbs such as mint or lemon balm are often used. 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 the color of the natural product. Whole fruits with hard pulp are usually fumigated: 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 laid on braziers with charcoal, which are installed indoors, observing fire safety rules, 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.

Introduction…………………………………………………………………………….4
1 Market of canned vegetables and fruits………………………………..6
2 History of canning……………………………………………………..6
3 Principles for classifying food preservation methods……..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

The usefulness of fresh vegetables and fruits has always been known to man, and people have long learned to perfectly grow and preserve them.
Canned fruits and vegetables are fruits and vegetables that have been treated with high temperature or cold to protect them from microbiological spoilage caused by bacteria, molds and yeasts that develop under certain conditions (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. With 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 , cowberry. Basically, ripe fruits and berries are perishable foodstuffs. 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. During canning, perishable vegetables and fruits are stored for a long time without deteriorating 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. .) in 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 canning methods, which are based on sterilization at high temperatures, can be considered 1795, that is, the period of the Napoleonic campaigns, when the 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, French chef Nicolas François Appert won a competition for the best way to keep food for a long time. 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, but the nutritional value and taste remain! 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). A tin can was filled with products intended for canning, heated with steam or 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 importance of food metabolism (metabolism), both of the starting materials and the need for human metabolism, for which there are enough basic nutrients such as saccharides, lipids and proteins and biocatalysts, especially 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 during pickling);
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 preservation (under the influence of high temperature - pasteurization or sterilization; under the influence of low temperature - pickling and urinating, 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 until fully cooked (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 temperature, preservatives (for example, vinegar), salt, sugar, dehydration interfere with microbes' existence.

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

Preservation under high temperature is the most effective method, based on the destruction of most 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, the following rules should be remembered: 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, 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.................

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 methods of food preparation. You can dry the food in the air or in the oven.

For drying in the air, the washed fruits are cut into 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. The well-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 table 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: pickled vegetables contain less salt, so lactic acid bacteria and, accordingly, lactic acid are produced more. For example, sauerkraut contains 1.5-2.5% 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. It gives the finished product a 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 suffering from diabetes, sweeteners (xylitol, sorbitol) are used in conservation.

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 1 930 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 liters of water).

The readiness of jam can be determined in 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 from ready-made jam does not spread on a saucer when cooling. 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 the 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 materials will freeze evenly, less ice will form in the package, and it will be easier to defrost.

To defrost, the product can be poured with hot water or heated in a microwave oven. You can also defrost in a natural way - wait until vegetables or fruits thaw.

Eduard Semenovich Gorenkov

Alla Nikolaevna Gorenkova

Galina G. Usacheva

"TECHNOLOGY OF PRESERVATION"

TEXTBOOKS AND TEACHING AIDS FOR TECHNICIUM STUDENTS

For students of secondary specialized educational institutions studying in the specialty "Technology of canning fruits and vegetables."

Approved by the Office of Higher and Secondary Specialized Education of the State Agro-Industrial Committee of the USSR as a textbook for secondary specialized educational institutions in the specialty 1009 "Canning Technology"

MOSCOW IN "AGROPROMIZDAT" 1987

The textbook is written in accordance with the program of the course. The technological processes of production of canned fruits and vegetables, sorting, washing, grinding of raw materials, various thermal processes, as well as issues of technology for the production of certain types of canned food are covered. The material on the complex processing of vegetable raw materials is included.

© VO "Agropromizdat", 1987.

Analysis and evaluation of the quality of canned food by microbiological indicators / [N. N. Mazokhina-Porshnyakova, L. P. Naydenova, S. A. Nikolaeva, JI. I. Rozanova]. - M.: Food industry, 1977. - 471 p.

Aseptic preservation of fruit and vegetable products [Ed. V. I. Rogacheva]. - M .: Light and food industry, 1981. - 287 s,

Volkina I. L. Complexes for storage of potatoes, vegetables and fruits. - M.: Kolos, 1981. - 223 o.

Wild M. Ya., Mal's'kiy AN Technological equipment of canning plants. - 4th ed., revised. and additional - M.; Food industry, 1973. - 423 p.

Zhvirblyanskaya A. Yu., Bakushinskaya OA Microbiology in the food industry. - M.: Food industry, 1975. - 501 p.

Ilchenko S. T., M a rkh A. T., Fan-Yung A. F. Technology and techno-chemical control of conservation. - M.: Food industry, 1974. - 423 p.

K a c 3. A. Production of dried vegetables, potatoes, fruits. - M.g Light and food industry, 1984. - 216 p.

Korobkina G. G. Baby food products. - M.: Food industry, 1970. - 294 p.

Malsky A.N., Izotov A.K. Canned vegetable snacks. - "M.: Food Industry, 1978. - 229 p.

M a r x A. T. Biochemistry of conservation of fruits and vegetables. - M.: Food industry, 1973. - 371 p.

Nazarova AI, Fa n-Yu ng AF Technology of fruit and vegetable canning. - M.: Light and food industry, 1981. - 239 p.

Processes and; food production machines [B. N. Stabnikov * V. D. Popov, V. M. Lysyansky, F. A. Redko]. - M.: Food industry, 1976. - 663 p.

Rogachev V.I., Babarin V.P. Sterilization of canned food in continuous devices. - M.: Food industry, 1978. - 247 p.

Samsonova A. N., Usheva V. V. Fruit and vegetable juices. - M.: Food industry, 1976. - 275 p.

Handbook of the technologist of fruit and vegetable canning production / [A. N. Samsonova, L. I. Khalunnaya, G. N. Telyatnikova and others]; ed. V. I. Rogacheva. - M.: Light and food industry, 1983.- 407 p.

Freeze-drying of food products of plant origin / [V. G. Popovsky, L. A. Bantysh, N. T. Ivasyuk, and others]; ed. V. G. Popovsky. - M.: Food industry, 1975 - 336 p.

Technology for preserving fruits, vegetables, meat and fish. F. Fan-Yung, B. L. Flaumenbaum, A. K. Izotov and others]. - M.: Food industry, 1980. - 336 p.

Flaumenbaum B. L. Fundamentals of food preservation. - M.: Light and food industry, 1982. - 270 p.

Chemical composition of food products / [ed. acad. AMS of the USSR A. A. Pokrovsky. - M.: Food industry, 1976.- 228 p.

Schobinger U. Fruit and vegetable juices: translation from German. - M.: Light and food industry, 1982. - 472 p.

Electroplasmolysis/[B. R. Lazarenko, S. P. Fursov, Yu. A. Shcheglov and others]. - Chisinau: Kartya Moldovenyaska, 1977. - 299 p.

Yastrebov SM Technological calculations for the conservation of food products. - M.: Light and food industry, 1981. - 200 p.