What is the difference between shock freezing and conventional freezing. Shelf life of frozen foods

If earlier frozen products could only be seen in supermarkets, today every housewife freezes everything on her own and leaves everything “until better times”. But the trouble is that not everyone knows the rules for freezing food, how long and under what conditions they can be stored. Some do not even think about how the structure of products changes during freezing, whether they lose their properties, whether they can deteriorate. You will learn about this and more in this article.

How does freezing work?

Complete freezing in refrigerators with low temperatures takes 2-3 hours. With normal freezing Food is frozen in three stages:

1. From +20 to zero. This stage is called preparatory. Due to the gradual cooling, the product is prepared for freezing.
2. From zero to -5 degrees. This is an intermediate stage. Here the temperature fluctuation is insignificant. The main thing at this stage is the process of liquid crystallization in the tissues of the product.
3. From 5 to 18 degrees with a minus sign. Final stage. At this stage, everything that did not have time before is frozen.

Food freezing rules

In order not to spoil the product and keep it for a long time, you must follow the simple rules of freezing:

1. Freezing Products must be fresh. If something has already gone bad, don't expect the freezer to do a miracle. It is better to decide immediately after the purchase what you will cook and what you will leave "until better times."
2. Then the product must wash and dry well cut into pieces or boiled.
3. Choose suitable dishes or special bags (most importantly, keep food away from air and moisture) and lay out the prepared product in small portions. Why small? If you need to cook ten cutlets, you will not defrost two kilograms of minced meat. Therefore, it is better to divide the products in small portions.
4. So that they lose less vitamins and do not get chapped, try prevent too much air from entering the package. But do not fill the containers to the top: when frozen, the products increase in volume and can lift the lid.

Useful properties and freezing

If we talk about frozen cucumber and bought in the winter in a supermarket, then in the first, of course, there are much more useful properties. After all, greenhouse products that are sold out of season are processed and lose most of their properties. But if we compare the product just plucked from the garden and defrosted, then the first, of course, is more useful.

Vitamin C is lost the most during freezing. But any other treatment also kills it. Thiamine (vitamin B1) is lost during freezing about 25%, riboflavin (B2) - 4-18%. Freezing does not affect vitamin A in any way, but long-term storage kills it. Therefore, do not keep frozen carrots for too long, cook them.

Shelf life of frozen foods

Nothing lasts forever, including frozen foods. Even with the most proper storage, products will still deteriorate sooner or later. Here is a sample list of frozen food expiration dates:

• minced meat - up to 2 months;
• sausages - up to 2 months;
• homemade meat and fish dishes - up to 3-4 months;
• small fish - a maximum of 3 months, large - twice as much;
• rabbit, duck, goose and hare meat - six months;
• turkey and chicken meat - 9 months;
• liver - 3 months;
• milk and dairy products - from six months to a year;
• vegetables - 10-12 months, in soup sets - 6-7 months;
• mushrooms - 5-6 months;
• fruits and berries - up to a year;
• greens - 3-4 months;
• flour products - up to 3 months.

In order for the product to stay fresh longer, it must be stored properly. There are such rules:

1. Before freezing, the product is prepared in such a way that it does not need to be washed after defrosting.
2. Freshly prepared dishes should be cooled to room temperature, and only then sent to the freezer.
3. Freeze only fresh foods, those that have begun to deteriorate are best cooked immediately.
4. For better preservation, food should be frozen quickly.
5. The packaging in which this or that product will be stored must be airtight.
6. Label each bag with the freeze date so you know when the expiration date is.
7. If food is defrosted (due to a power outage), it cannot be refrozen. It is better to cook their dishes right away.

Deep frozen products

This term is more common on an industrial scale. Deep frozen products include vegetable products and semi-finished products.

You can also find frozen berries, fruits, vegetables, mushrooms and a variety of mixtures in stores. A separate place today is occupied by semi-finished products: cutlets, dumplings, pizza crusts and much more.

Shock freezing: technology

Shock freezing is very different from the one that everyone is used to. There are no separate stages here, the product is cooled very rapidly by lowering the temperature to -30-35 degrees and increasing the air flow. With this technology the product is exposed to frosty air from all sides and freezes much faster.

Advantages and disadvantages

Freezers have many advantages:

• products lose 2-3 times less useful properties than with conventional freezing;
• the freezing time of products is reduced from 3 to 10 times;
• the production area is reduced by one and a half to two times;
• need less staff by 25-30%;
• pays off more by 15-20%.

Among the disadvantages of this technology is only that special equipment is required. And for the household, shock freezing is hardly suitable, it is more designed for industrial scale.

"Shock" equipment

For shock freezing, the following freezers are used:

1. Fluidizing - most often used for freezing chopped vegetable and fruit raw materials.
2. Conveyor - used for freezing ready meals.
3. Cradle - used for freezing packaged semi-finished products from fish, meat and poultry.
4. Spiral - designed for freezing portioned dishes.

Mistresses about freezing

Yana:

“When I bought a refrigerator with a freezer, I tried to freeze everything that came to hand. I folded everything in small portions, and thawed it every other day to try it. I liked the most frozen melons and watermelons. Even now, when I defrost them in winter, there is such a smell in the house ... "

Nika:

“I am sure that freezing retains more of the health benefits than any other canning method. Therefore, I put everything in my freezer in a row: greens, mushrooms, herbs, fruits, berries. It's incredibly convenient."

Throughout its history, mankind has been looking for ways to preserve food products indefinitely without loss of nutritional and taste properties. Refrigeration and freezing have been used by humans for a long time, but it wasn't until the 1920s that North American naturalist Clarence Bearsday discovered the role of extreme cold while observing Newfoundland fishermen. They prepared fish in a special way, freezing it almost instantly at -40 ° C. After thawing, the product had the properties of a fresh catch. However, only 70 years later, shock freezing technology became widespread and began to play a key role in increasing the competitiveness of enterprises that prepare meat products, fruits, vegetables, confectionery and other nomenclature of the food industry.

Learn more:

shock freezing- freezing of foodstuffs in the temperature range of +90/-18 for no more than 240 minutes.

Benefits of shock freezing

Shock freezing of fish, meat, vegetables, fruits, according to the calculations of companies that have switched to a new technology, reduces the cost of production in several ways at once:

• Reducing the total time of preparation for long-term storage - on average, 6 - 7 times. This allows you to significantly increase productivity in old production areas. In addition, it becomes possible to reduce the production area by 2 times, while maintaining the volume of production of frozen products;
• Reduction of staff - on average, by 30%;
• Reducing direct losses (freezing). Instead of 10% of the mass, no more than 1% is lost.

In addition to a significant cost reduction, the manufacturer receives a direct competitive advantage due to:

• Significant improvement in product quality;
• Refusal to use harmful preservatives;
• A multiple increase in the allowable storage time;
• Building a cheaper optimized logistics process. After all, such a business is much less dependent on cyclicality and problems with suppliers.

A deep-freeze shop pays off 17% - 20% faster than a cold store with traditional equipment. In addition, the range of blanks is expanding significantly. Most of the specific competitive advantages that a deep-freeze line brings to the business of meat, meat products and fish are equally characteristic of working with crop products (mushrooms, berries, vegetables, fruits, herbs).

What is the secret of the blast chilling process?

Why did Clarence Bearsday's discovery take so long to hit the market? The thing is that he copied the method itself in his pilot productions, not knowing the theoretical background of the process. It was mistakenly believed that the special properties of the workpiece depend only on the extremely low temperature, which must be maintained throughout the storage period. The role of temperature dynamics was not clarified, so the introduction of technology often turned into a failure: more time was spent on processing the product than before, but it was not possible to obtain a clear gain in quality and shelf life.

Only at the end of the 20th century, studies of the low-temperature destruction of biological tissues dotted the "and". It turns out that the key to success lies in stopping the formation of ice crystals. The faster the phase change of the substance occurs, the greater the number of ice fractals (rudiments of crystallization) is formed, but the smaller their size.

For example, with traditional meat freezing, which lasts 2 - 2.5 hours, the density of fractals is less, but their size is orders of magnitude larger. Large crystals break tissue membranes and damage the cellular structure. As a result, muscle fibers are stratified, torn, crushed. Nutrient juices enter the interstitial space. Such meat after defrosting is very different in its properties from fresh meat: it is more rigid after cooking, its microtexture becomes unnatural, taste and aroma properties are largely lost. In addition, the qualitative composition of vitamins and enzyme groups deteriorates significantly. In addition to the loss of consumer properties, low-temperature degradation affects the loss of the product with the so-called freezing, which directly depends on the ingress of juices into the interstitial zones.

In addition to stopping the growth of ice crystals, there is another bonus that the shock freezing device gives to the manufacturer and the end user - this is a reduction in the time of the first stage of the process (temperature decrease from plus to zero). The high speed of passage through this zone protects against the development of colonies of microorganisms that originally exist in fresh meat products, vegetables, fruits and berries.

Deep Freezing Equipment

To increase the speed of the process, in addition to powerful heat exchangers, shock freezers (the so-called shock freezing units) include special fans that increase the heat exchange of the product with air. Another way to intensify freezing is in contact with special metal elements: they can be made in the form of rolls or plates that softly press parts of cut carcasses or fragments previously enclosed in a special package.

Deep freezing of products, the equipment for which has hundreds of models of dozens of brands, according to the combination of loading and heat exchange systems, is divided into:

1. Chambers (cases) of a shock freezing. Used in food industry, trade, public catering for rapid cooling or freezing of finished products and semi-finished products;
2. Conveyor freezers. As a rule, they are intended for preparation for long-term storage of fragments up to 25 mm thick with dimensions of about 100 x 100 mm. On such equipment, for example, the processing of cut chicken is carried out;
3. Cradle cameras. They carry out shock freezing of semi-finished products of most types: cutlets, meatballs, sausages, ready-made second courses. Products enter the apparatus, as a rule, in vacuum packaging, with a complete set weight of not more than 1 kg;
4. fluidization chambers. Suitable for small fragment products, regardless of their type. It can be fruits, berries, small fish, etc. Record-breaking fast air heat exchange is achieved;
5. Spiral freezers. Designed for extreme freezing portioned meat and vegetable dishes.

Features of freezing products

The quality of shock freezing is speed. In principle, any product can be frozen in any configuration and packaging. But how economically viable will it be? The main principle of processing meat products in shock freezing chambers is the optimization of heat exchange due to all components of the process: the temperature of the cooling medium, the flow rate of this medium, the speed of the product passing through the chamber, and, finally, the size of the packaging. It is this last element that is the subject of the main preliminary preparation - high-quality cutting.

Now in any supermarket you can find a huge amount of frozen convenience foods, vegetables and fruits. Many products are frozen: fish, meat, confectionery, bakery, even first and second courses.

What are the benefits of freezing?

Why did chilled semi-finished products come into fashion? First of all, it is very convenient for both buyers and manufacturers. People without much time can prepare a good and tasty dish. As for producers, frozen products are very profitable for them. There is no need to spend money on a large number of staff, and there is practically no unsold goods, which means that losses are reduced and income is growing. Shock freezing is currently used to cool food. What it is?

Shock freezing products

Why is this type of storage so good? The fact is that with ordinary cooling, water molecules turn into crystals. The faster the freezing process itself takes place, the smaller these very crystals will be. Why is it important? Yes, because only with microscopic water crystals, the molecules of the products are not destroyed at all.

Such freezing is carried out in special devices. They are called shock freezers. Cooling in them products occurs at a temperature of -40 degrees Celsius. This allows you to freeze the core of vegetables or fruits in just two hundred and forty minutes. Thanks to this, the product structure remains the same. After defrosting, there is no effect of liquid loss, neither the taste nor the consistency changes.

Benefits of shock freezing

The cabinet of shock freezing in comparison with traditional refrigerating chambers allows:

• Reduce the loss of products several times.
• Reduce the freezing period by up to ten times.
• Cut the production area in half.
• Reduce the number of staff by thirty percent.
• Reduce the payback period by twenty percent.

Products structure

Shock freezing is, first of all, a high cooling rate. The temperature in the cell reaches minus thirty-five degrees. This allows the product to quickly pass from the liquid phase to the solid. In this case, small crystals are formed, and cell tissues remain intact. As a result, the properties of the fresh product are preserved, unlike conventional freezing.

The technology of shock freezing allows not to use thermal and chemical processing of products. As a result, the type of proteins does not change at all, and therefore the biochemistry of substances remains unchanged. The low temperature of shock freezing and the speed of the process itself reduce the activity of environmental bacteria. With slow cooling on berries, fruits and vegetables, traces of vital activity of bacteria may remain. Shock freezing virtually eliminates the development of such an effect.

Weight of products

With a long freezing process, weight loss of products occurs. This happens due to the evaporation of the liquid. Usually lost up to ten percent. Shock freezing has a forced cooling rate that reduces moisture loss by up to one percent. The difference is palpable.

Do tastes change?

Since the product does not dry out during quick freezing, the nutritional and aromatic properties are practically not lost. So, both nutritional qualities and taste remain the same.

Shelf life

Products chilled using the shock method have a longer shelf life than those frozen in conventional freezers. In addition, they are able to retain all qualities for a longer time. It should be noted that quick freezing is the best way to prepare for the winter.

The popularity of frozen foods

Quick-frozen semi-finished products, products and ready meals have gained immense popularity all over the world. Their production is increasing every year. The range of products that are frozen all over the world is unusually wide. Moreover, each country is engaged in the production of those vegetables and fruits or semi-finished products that are typical for a given region, climate, and traditions.

Currently, the range of frozen products consists of:

• Vegetables, fruits, berries, gourds, herbs, as well as various mixes of them.
• Ready-made second and first courses, pies, confectionery and bakery products.
• Fish and meat semi-finished products: steaks, entrecote, cutlets, hamburgers, dumplings, sticks, dumplings, sausages.
• Juices, desserts, jellies, puddings, ice creams, etc.

The popularity of frozen foods is due to a number of reasons:

• Easy storage and quick readiness when needed.
• Cooking does not take much time.
• Good taste qualities.
• The product is packaged and dosed.
• No additional preparation is required (such as peeling or cutting).
• Almost all of the product is edible (except packaging).

Business

Shock freezing technology provides completely new possibilities for activity. We can say that the conditions for doing business are becoming more comfortable. When using this technology, the number of losses is significantly reduced. Moreover, the terms for the sale of the same agricultural products are significantly increased, and the place of processing may be located in a completely different region.

The product can be sold in different places and even countries. There is no restriction of seasonality of goods. In addition, the sale can be carried out with a delay in time in order to wait for a better price. At first, the frozen food market in Russia consisted of imported raw materials. And now the priorities have gradually shifted towards domestic producers.

Freezing equipment

Speaking of quick freezing, you need to understand that it is possible only with special equipment. The advantage of this technique is a quick payback. The cabinet of a shock freezing allows to cool semi-finished products, vegetables, fruit.

Freezing equipment is different. It is divided into the following types:

• Fluidization devices designed for freezing small raw materials from vegetables and fruits, berries, soup mixtures and stews. Possible is the cooling of small fish, shrimps, mushrooms. Equipment of this type has the highest freezing speed, which means it retains the best quality of products.
• Conveyor cabinets are used for freezing fish, meat, flour, dairy semi-finished products, as well as ready-made meals: puff pastry, pancakes, meatballs, steaks, dumplings and dumplings.

• Cradle freezers freeze packaged semi-finished products from fish and poultry meat, cutlets, steaks, confectionery, second and first courses.
• Spiral freezers are designed for cooling portioned products from vegetables, fruits, meat and fish, breaded semi-finished products.

Freezing of semi-finished products

Since semi-finished products are especially popular with consumers, the shock freezing of dumplings, dumplings, chebureks, pancakes make up a significant share of production.

However, a new activity has also emerged. The market of frozen foods has replenished with semi-finished bakery products. Frozen pastries are very popular and in demand. There are more than a hundred items in the range. These are buns with additives, and baguettes, and bread. Such products before eating only need to be warmed up a little. The taste qualities of frozen bakery products do not differ from freshly baked ones.

Experts in this field claim that such bread is made from natural products, there are no special additives in them. The correct technology for the production of bakery products from blanks makes it possible to obtain a crispy and tasty product. Naturally, obtaining good frozen semi-finished products is only possible with high-quality and correct equipment.

In any food cooked and left to cool slowly, at a temperature of +65 to +10 ° C, the microflora rapidly multiplies (approximately, bacteria doubling every 20 minutes). With a rapid decrease in temperature in the body of the product, a rapid reduction in the reproduction of microflora occurs. Microorganisms of different species have different temperature limits of vital activity. With a slow decrease in temperature, traces of vital activity of very many microorganisms appear in the product, while with a fast decrease, many of them simply do not have time to develop. Thanks to this, the shelf life of quick-chilled and quick-frozen products is longer.

When frozen, all water molecules turn into ice crystals, and the faster the process, the smaller the crystals. Thus, only during micro-crystallization, the product molecules are not damaged. As a result, after defrosting, there will be less loss of liquid, the consistency and taste of the product will not change.

Shock freezing systems allow reaching a temperature of -18°C in the body of the product in less than 240 minutes - the maximum time during which it is necessary to carry out the freezing process for micro-crystallization, while maintaining the organoleptic properties of the product unchanged.

Blast chilling differs from shock freezing in the temperature of the product at the outlet. During blast freezing (shock freezing) the product comes out with a negative temperature of -10...-20°C, and during blast chilling it is usually +3°C (i.e., the process just ends earlier). In both technologies, the process of lowering the temperature of the product occurs quickly.

Shock chilling can be "soft" (soft) and "hard" (hard). The first option is suitable for delicate and thin products, the second for dense, fatty and large.

In the West, devices for shock freezing are called shock freezers (shock freezer), and for shock cooling blast chillers (blast chiller). For small product capacities (for example, in mini-bakeries), miniature serial samples of batch equipment in the form of shock freezers are used. For industrial production, as a rule, fully automatic equipment of continuous action is used - a shock freezing chamber. Such systems are designed and manufactured for a specific manufacturer.

Advantages of using shock technologies:

1. Due to the longer shelf life, it becomes possible to better plan production, prepare inventory less often repeating the production process. This results in time savings of up to 30%.

2. Due to the long shelf life of products, it makes it possible to save on the purchase of seasonal ingredients (at lower prices and of higher quality (fresh)).

3. Allows you to increase revenue from the sale of weight products (up to 6% increase) due to less weight loss.

4. The use of technology helps to obtain a product that truly meets the standards of the HACCP food safety management system.

5. Allows you to expand the range of products offered.

SHOCK FREEZING OF BAKERY AND CONFECTIONERY PRODUCTS

In the West, frozen bread today occupies about 70-80% of the entire bread market, in Russia - so far only 10-15%. According to experts, the transition of large producers (bakeries) to new technologies and the production of frozen bread for the mass segment can provide an increase in profitability and quality compared to the traditional process. The difference in the production of ordinary and frozen bread is an increase in the cost of freezing and storing products (from 15 to 30%), but a decrease in the cost of returning unsold products from contractors, logistics, damping surges and dips in demand due to long-term storage inventory.

The global market for frozen products is developing much more rapidly than the Russian market, where frozen pastries appeared in the early 90s. For example, in Europe, the production of partially frozen bakery products has become widespread since the 1970s.

The consumers of frozen bakery and confectionery products are the HoReCA sector - cafes, restaurants, the "street food" or street food segment, catering enterprises and individual consumers. The largest part of the sale of frozen bakery products in Russia through retail channels falls on grocery stores, markets and supermarkets.

As experts predict, the demand for such semi-finished products will grow not only in the capital, but also in the regions, and companies offering a wide range of products new to the market will become in demand.

In addition to bread and rolls traditional for the Russian consumer, small-piece products are subjected to shock freezing - rye and wheat buns with various additives, mini-baguettes, classic baguettes of various sizes, almost ready-made dishes from frozen bread (for example, sliced ​​baguette with butter and herbs, baguette with garlic oil), which need only be warmed up before use. Shock freezing is also widely used for products such as bagels, pretzels, pizza, lasagne, sausages in dough, tartlets, flatbread, khachapuri, panini, ciabatta, focaccho, Finnish rye bread, Irish soda, strudel, cheese sticks, pretzels and envelopes with various fillings, cakes, pastries, pies, pancakes, pies, puff pastry (yeast-free and yeast-free), croissants, cheesecakes, muffins (muffins), donuts (donuts), puffs, denishi, cheesecakes, cookies (cookies), etc. d. In total, there are about 300 types of frozen bakery and confectionery products in the world. More than 100 are represented on the Russian market. Only about 10 of them are the most universal and popular, the rest are narrowly focused - for a certain cuisine, for a certain dish, etc.

In recent years, the demand for products made from frozen semi-finished products has increased significantly. As for the taste characteristics, according to experts, there is no pronounced difference between bread baked in a bakery or from frozen semi-finished products. As a rule, frozen products are made from natural ingredients without special additives and improvers. With proper observance of the technology for the production of bread from frozen blanks, the products turn out to be more crispy (in comparison with bread produced in the classical way), which makes them especially appetizing. The stereotype that frozen products are obviously of lower quality than fresh ones is no longer so strong. Restaurateurs and their clients are convinced that the "freeze" not only does not betray itself in appearance, but is absolutely identical to fresh counterparts in terms of taste.

What is the attraction of quick-frozen foods? First of all, it's convenient. Convenient for both the consumer and the manufacturer. For the consumer, because such a product requires a minimum of time and labor for its preparation. Is everything ready. And for the manufacturer, such products have a number of advantages. So, the use of frozen semi-finished bakery products in shopping centers does not need to expand the staff at the expense of specialists who carry out the dough process. Also, when using, for example, frozen semi-finished bread products, there is practically no unsold goods, since new batches are baked as the previous ones are sold. As a result, hot and fragrant bread is always present in the assortment.

Today, there are three main ways to freeze bakery and confectionery products:

1. Freezing dough pieces.

2. Freezing of partially baked products (part baked). This type is also called the “incomplete baking” production technology.

3. Take bake technology - freezing finished products.

The first method may have options. Here are two of them.

First option. The test piece is allowed to rest a little. Then frozen and stored. Preparation: defrosting (defrosting) for 30 minutes, proofing for 2...4 hours at +20...+25°C and humidity 70...75%, baking for 10...25 minutes.

Second option. After molding, the dough pieces go through the final proofing stage. Then the dough pieces are frozen in a shock freezing chamber at a temperature of -30...-40°C, packed in the so-called "zero chamber" (0°C) and stored at a temperature of -18°C. Further actions with blanks - defrosting for 15-30 minutes. at room temperature, then baking in an oven or combi steamer.

In the second method, the product is baked until 50-90% cooked. The bread is then deep-frozen. Frozen bread is stored at -18°C. Today, many manufacturers use this technology. To make bread, it is taken out of the freezer, thawed and baked in ovens until cooked. Fresh hot bread is ready.

The latest know-how in the production of frozen bakery and confectionery products is the baking of semi-finished products without prior defrosting, which further simplifies the process of preparing products.

In the third method of freezing, products are brought to readiness by heating in a microwave oven.

The detailed technology for creating a semi-finished product, shock freezing, cooking after storage for each specific type of product is always individual. As a rule, this technology is know-how and organizations using it are very reluctant to share it. The technology for different types of products can differ significantly due to their features.

Depending on the additives used, the shelf life of some products can be up to 1.5 years. With strict observance of technological parameters and careful quality control of raw materials, the resulting semi-finished puff pastry products can be stored frozen for up to 6 months without the slightest loss of their properties.

Deep freezing is suitable for products prepared according to a wide variety of recipes. Exceptions are butter cakes and products decorated with vegetable cream cream. The fact is that when defrosting, cracks appear on the surface of the cake, and it loses its presentation.

When working with deep-frozen confectionery, it is important to strictly follow the rules of storage and defrosting. It is recommended to defrost products gradually at a temperature of +2...+5°C (in a conventional refrigerator) for 2 hours. The implementation period in the future is 72 hours, provided that the product is stored in the refrigerator. If the storage and defrosting conditions are violated, the product shrinks, the taste quality deteriorates, and in addition, some of its deformation is possible. Note that manufacturers of frozen cakes and pastries also allow other methods of defrosting: at room temperature or in a microwave oven in defrosting mode.

A few words should be said about the features of shock freezing of yeast dough. Keep in mind that too high or too low a quick freeze rate can cause damage to yeast cells, even when specialized yeasts are used. The acceptable freezing technology for yeast dough is determined by professional technologists of the enterprise that manufactures such products. They determine the conditions under which the maximum survival of yeast is maintained.

EQUIPMENT FOR SHOCK FREEZING OF BAKERY AND CONFECTIONERY PRODUCTS

Bakery and confectionery products are frozen at -20 to -70 °C, depending on technological requirements. The duration of the freezing process depends on the size and thermophysical properties of the product and can vary from 15...20 minutes (puff pastry) to 3...4 hours (cake).

Fully automatic blast freezing line consists of the following components

(types of equipment classified by functional purpose):

1. Receiving conveyor system with the function of forming the required layout of products on the tape *
2. Product rejection system based on vision system
3. Thermal insulation chamber made of sandwich panels
4. Spiral or multi-tier cold conveyor with possible additional options (e.g. belt cleaning and washing system)
5. Refrigeration equipment (air cooler (special heat exchange unit with shock-froster fans), compressor and receiver unit, condenser, oil cooler, etc.)
6. Intermediate conveyor system* that takes products from the chamber and transports them to the loading device in the packaging machine (feeder)
7. Multifunctional control panels with alarm system
8. Feeder
9. Packaging machine with labeling capabilities
10. Intra-factory logistics system (includes a conveyor system for containers (group packaging) and elements of its automation (product counters, robotic arms, palletizers, etc.)

* As additional options, equipment for confectionery production can be supplied with belt cleaning systems, removable crumb trays, protective covers against dust on the product (see more details) can be installed on conveyors, and more powerful refrigeration units can also be used. installations (industrial).

In conveyor systems for lowering products between levels, inclined, steeply inclined, spiral, vertical conveyors, as well as straight (hills), curved and screw gravity descents made of stainless steel are used.

The heat-insulating chamber is made of "sandwich panels". The thermal insulation material can be different: polyurethane foam (PUR), non-flammable polyisocyanurate (PIR), etc. The most commonly used polyurethane foam (PPU). The outer layers of the sandwich panel can be made of galvanized cold rolled steel with various coatings or stainless steel. The design of the joints (thorn-groove connection) of the chamber can be of lock type (with built-in eccentric locks and a deep profile at the ends), profile (with PVC profiles) and lockless types. With any type of chamber, a tight fit of the panels, rigidity of the structure and the absence of cold bridges are ensured. With a lock design, it is easier and faster to assemble the camera. the use of sealants, sealants, "additional" elements and hardware is not required. This reduces installation costs, but the cost of such a camera is higher than without locks. The chambers have reinforced floor panels. As a rule, the floor panel is reinforced with special plywood and corrugated aluminum sheet. In the room, the low-temperature chamber is installed on the air. The chamber must be provided with drainage and a lighting system. The chamber has special windows for the entry and exit of the product. As a rule, the exact location of these windows is determined during installation. In addition to these windows, the chamber must have at least one refrigerating door for service personnel. When designing a shock freezing system, it is necessary to take into account the ease of maintenance of the conveyor and the heat exchange unit, the required installation distances of the heat exchange unit.

A spiral conveyor is most often used as a technological conveyor for a shock freezing chamber for bakery and confectionery products. CJSC "LIPSIA" has vast experience in the production of spiral conveyors (more than a hundred spiral conveyors of various applications have been installed).

As chamber equipment, heat exchange blocks with an increased spacing of fins of the heat exchange surface are used, which makes it possible to increase the operating time of refrigeration units of industrial equipment between defrost cycles (6...8 hours). At the beginning of a shift in a production facility with an automatic system of shock freezing, the chamber is brought to the mode, then a long-term supply of the product flow to the conveyor belt begins, transporting it to the chamber. Thus, between defrost cycles, the mode of the freezing process does not change (remains consistently fast). This explains the higher quality of the frozen product compared to other methods.

Different heat exchange units are used for different products. Sometimes it is necessary to order non-standard heat exchange units (for example, with slowly blowing fans for freezing cream cakes).

An important role in shock freezing is played by the organization of air flows in the refrigerating chamber. To direct the air flow, a special lining made of stainless steel sheet is installed. An improperly designed blast chiller system may not work or may not work efficiently enough.

CJSC "LIPSIA" has a subdivision that is engaged in the design of climate equipment. When creating refrigeration systems, components of various companies are used, depending on the preferences of the Customer. However, to achieve the best result, the company strongly recommends using brands that have been proven over the years - such as: Bitzer (Germany), Güntner (Germany), GEA Goedhart (Netherlands), Thermofin (Germany), Alfa Laval (Sweden), Danfoss (Denmark).

Frozen products can be wrapped in film using flow-pack packaging machines. It is also possible to pack products in various trays with subsequent sealing. With such packaging methods, it is possible to carry out the freezing process of already packaged products. However, this is often not possible due to a number of factors: difficult heat transfer prevents quick freezing, the stickiness of an unfrozen semi-finished product prevents packaging, the quality of the packaging material and printing does not allow maintaining the presentation after the shock freezing process, etc.

Often frozen products are packed in corrugated containers. For example, a given number of frozen pies needs to be packed into a corrugated cardboard box in automatic mode. In this case, a case packer can act as a packaging machine for frozen semi-finished products. This equipment is for group packaging in corrugated boxes. The following operations are performed in automatic mode: forming a box from a blank, grouping and stacking products in a box, closing valves, sealing the box valves with adhesive tape.

In the system of intra-plant logistics, packaged products are automatically considered, fall into containers, which are then fed into storage (cold storage of finished products) or into refrigerated transport for further shipment to points of sale.

The line described above is fully automatic. However, such lines, due to their high cost, are not widely used in Russia. At most domestic enterprises, shock freezing lines are installed, partially automated (some of the line components are missing) or not automated at all.

Fully non-automated shock freezing line is as follows. Workers transfer ready-to-freeze semi-finished products to trays in tiers of special mobile carts. Then these trolleys are rolled into a shock freezing chamber, where the products are frozen. Appropriate heat-exchange units of the “shock-froster” type are also installed in the chamber. Then the trolleys are again manually removed from the chamber, the products are removed from the trolleys and packaged. Such chambers are intermittent equipment. In contrast to the automatic system, due to the large heat gains during loading and unloading, the chamber takes a long time to enter the mode. Such lines are characterized by low product quality (damage to product tissues by large ice crystals) and a large share of manual labor and, as a result, low profitability of production as a whole. At enterprises with such lines, there is an irrational use of production space, a large payroll, frequent confusion in the organization of intra-factory logistics and shortages of products, a high percentage of defects, downtime due to the "human factor", dissatisfaction with working conditions. A fully non-automated line is relatively cheap, and therefore, with low productivity (up to 300 kg / h), such equipment is still used.

Advantages of the system of shock freezing of products based on a spiral conveyor:

• Reducing the payroll
• Significant reduction in labor intensity
• Saving production space
• Reducing the number of defective products (excluding the "human factor", rough impact)
• Improving the consumer qualities of the finished product
• Increasing the implementation time (minimizing the development of microflora, eliminating or minimizing the contact of products with people)
• Organization of a continuous technological process
• Reducing freezing time

The transition to full automation of production from the test process to the receipt of products at the warehouse allows enterprises to take one of the leading positions in such important indicators as quality and price.

In progress shock freezing products three temperature ranges can be distinguished in the center of the product from +20 to 0 °С, from 0 to -5 °С and from -5 to -18 °С.

At the first stage the product is cooled from +20 to 0 °С. The decrease in the temperature of the product here is proportional to the amount of heat extraction work.

At the second stage of shock freezing there is a transition from the liquid phase to the solid at temperatures from 0 to -5 ° C. The work on the removal of heat from the product is very significant, however, the temperature of the product practically does not decrease, and about 70% of the liquid fractions of the product crystallize, which we call freezing.

At the third stage freezing occurs at product temperatures from -5 to -18 ° C. The decrease in temperature again goes in proportion to the work performed by the refrigeration machine.

Traditional freezing technology, implemented in the form of so-called low-temperature refrigerating chambers, assumes a temperature in the chamber of (-18) - (-24) °C. Freezing time in refrigerators is 2.5 hours or more. During freezing, the speed of the process acquires a decisive role. A close connection between the quality of the product and the rate of freezing has been established. Numerous experimental data testify to the influence of the freezing rate on the size of ice crystals, on structural and enzymatic changes in products.

technology idea shock freezing of products (meat, vegetables, fruits, berries) consists in forcing the modes of cooling, freezing and freezing of products. This forcing is provided by two means of increasing the rate of heat removal from the product: lowering the temperature of the medium to (-30) - (-35) ° С; accelerated movement of the coolant (in the role of which air acts in the chamber), which is ensured by the ventilation of the evaporator and, accordingly, by intensive blowing of the product. It should be noted that a further decrease in temperature leads to unjustified power consumption and increased deformation of the product, the unevenness of the process becomes too great.

Benefits of shock freezing

Compared with the traditional way of freezing on racks in cold rooms, the advantages of using shock freezing products are:

• Product losses are reduced by 2-3 times;
• Freezing time is reduced by 3-10 times;
• Production areas are reduced by 1.5-2 r
• The production staff is reduced by 25-30%;
• The payback period is reduced by 15-20%;

Consider the practical results of the application of the technology of shock freezing of products.

total freezing time

If with traditional technology the total freezing time for dumplings and cutlets is 2.5 hours, then with quick freezing it is 20-35 minutes, which gives a significant economic effect. The time for passing the second stage is reduced from 1 hour to 15 minutes.

Fabric structure

The high cooling rate provided by the shock temperature in the chamber (-30)-(-35)°С and intensive blowing of the product allows for a forced transition from the liquid to the solid phase. In this case, ice crystals are formed in much smaller sizes and almost simultaneously in the cell and intercellular partitions (cells remain intact). As a result, the tissue structure of a fresh product is preserved almost unchanged and better than with other methods of preservation.

Ecology and biochemistry

The absence of any thermal and chemical treatment (with the exception of blanching and ascorbic acid treatment, which are required by technology for some types of vegetables and fruits) and, as a result, the invariance of protein types make shock freezing of vegetables and fruits a method that absolutely does not impair environmental cleanliness and biochemistry product.

Bacteriological purity

Due to the speed of shock freezing, the periods of activity of the bacteriological environment are also reduced. Bacteria of different types have different (including below 0 °C) temperature zones of vital activity. During slow freezing, traces of the vital activity of each of these types of bacteria appear and remain in the product. During shock freezing, a number of types do not have time to develop.

Weight

Weight loss of the product resulting from the evaporation of the liquid (shrinkage) during freezing, in the usual mode, is up to 5 - 10% (depending on the temperature in the chamber and the product being frozen). Shock freezing mode reduces product weight loss up to 0.8%, which also gives a significant economic effect.

Taste and nutritional value

Due to the prevention of drying during quick freezing, aromatics and nutrients do not have time to leave the product, which preserves its quality. Nutritional value and taste remain unchanged.

Shelf life

The shelf life of products subjected to shock freezing (for example, meat) is longer than products frozen in conventional chambers. Quick-frozen foods retain their qualities better during long-term storage than fresh ones. Thus, the technology of shock freezing ensures the preservation of the qualities of a fresh product and makes it better than other methods of harvesting and storage.

Quick frozen foods

Frozen products, semi-finished products and ready meals are popular all over the world. Their consumption in countries such as the UK, Denmark, Finland, France, Germany, Sweden, Switzerland, the USA and Japan ranges from 40 to 100 kg per person per year. Moreover, their production in these countries increases by 5-7% annually.

In world practice, the range of products preserved by shock freezing is extremely wide. Moreover, each country produces, first of all, products specific to the region, climate, and traditions. In recent years, quick-frozen products have been especially intensively produced:

• Fruits, berries, vegetables, gourds, herbs and combinations of them;
• Ready-made first and second courses, pies, bakery and confectionery products;
• Semi-finished products (meat, fish, etc.) such as entrecote, steaks, hamburgers, meatballs, sticks, sausages, dumplings and dumplings;
• Desserts, juices, puddings, jelly, ice cream, etc.

What is the attraction of quick frozen products: The product is almost completely free from inedible inclusions. It is essentially "waste-free" (other than packaging); practically does not differ from fresh, retains all the original, natural properties; inherently dietary, conditioned; packaged, dosed, portioned. It is convenient for any consumer; For trade, public catering, for the end consumer, a quick-frozen product is strategic. It does not require attention during storage and is always ready for use;

Such a product requires minimal time (minutes) and labor for its preparation; The technology of shock freezing of products opens up completely new possibilities. It brings the business to a higher level of its development. Quick freezing allows you to delay the sale of agricultural products in time and move the place of sale in space. This is a kind of transport that expands the scope of sales of products not only by the region where it is grown and the harvest season, but also by other regions and seasons. This is a transport from summer to winter, from the field to the table.

For example, for farms, this is an opportunity to freeze part of their products and sell it directly to the consumer at a higher price than fresh, anywhere in Russia, the market for quick-frozen products was initially focused mainly on imported products. Now the priorities are shifting towards domestic production. Although the share of imports of fresh frozen fruits and vegetables is still large. The share of imported products in the total consumption of frozen vegetables and fruits in Russia in 1998 was 99.4%, and in 1999 it was 99.7%. From the foregoing, it follows that the undeniable advantages of shock freezing technology make it possible to recoup the reasonable costs of quick freezing equipment in a fairly short time. In addition, shock freezing technology is becoming a kind of standard for producers and consumers of frozen products, without which it is difficult to sell them.

Shock freezing equipment

The following types of equipment are used for shock freezing of meat, berries, vegetables, fruits and other products, semi-finished products and ready meals:

Fluidized quick freezers are mainly designed for freezing small-piece or chopped fruit and vegetable raw materials: fruits (plum, peach, apricot), berries (strawberries, currants, cranberries, blueberries), vegetable stews and soup mixtures (beets, carrots, zucchini, sweet peppers, cabbage ), french fries. Possible shock freezing of mushrooms(whole or in pieces), as well as small fish and shrimp. This class of equipment provides the highest (among air) speed of shock freezing, minimum shrinkage and maintains high quality of products. After freezing, the product retains its original crumbly structure and is perfectly packaged.

Conveyor quick freezers are designed for shock freezing of meat, fish, dairy, flour semi-finished products and ready meals: pancakes, puff pastry, pastries, meatballs, steaks, hamburgers, sausages, dumplings and dumplings, ravioli, etc. The thickness of the frozen products can be up to 25 mm, and the length and width up to 100 x 100 mm. These devices allow freezing up to 80% of the range of products traditionally frozen on imported spiral quick freezers.

Shock freezing with cradle equipment

Shock freezing of vegetable group products is also possible: mushrooms, strawberries, peaches, apricots. Cradle quick freezing equipment is designed for shock freezing packaged semi-finished products from poultry, meat and fish: meatballs, meatballs, steaks, hamburgers, sausages (including vacuum-packed), confectionery, as well as various side dishes and ready-made second courses. The thickness of the frozen products can be up to 80 mm, and the length and width up to 200 x 150 mm. The mass of one product (serving) can reach 1 kg, and the freezing time is 2.5 hours.

Shock freezing with spiral equipment

Spiral quick freezing equipment designed for shock freezing portioned dishes from meat, fish, fruits, vegetables, as well as breaded semi-finished products. When designing quick freezers, shockfrosters (air coolers with a large heat exchange surface, an increased distance between the lamellas to prevent ice rusting and a high air exchange rate) by GUENTNER (Germany) of the GFN series are used. As a compressor and condenser unit, they are usually used. More powerful shock freezing units are equipped with central units (refrigeration units consisting of two or more reciprocating or screw refrigeration compressors) with air condensers from GUENTNER (Germany) series GVV (vertical), GVH (horizontal), GVW (V-shaped).