This method of canning fruit and berry puree is most common in practice.
It lies in the fact that it introduces chemical agents (preservatives) that act bactericidal on the microorganisms of this medium at the dosage of them in small quantities. The main requirements for preservatives for fruit and berry puree are as follows: harmless to the human body in the doses used, chemical stability, i e. Unchanged chemical composition of the preservative throughout its duration, non-volatility and chemical indifference to the puree itself. It is necessary that the preservative had no effect on taste, color and jelly - forming ability of mashed potatoes and that it has good solubility in water.
There are a large number of chemical preservatives that are used in the food industry. Of these, applesauce is used in various countries: benzoic, sulfurous (formic, salicylic acid, isomers of the latter, salts of these acids and others.
In Ukraine, allowed to be used for fruit and berry puree, only two preservatives: benzoic acid and sulfurous acid.
Byenzoinaya kislota (C6Н5COOH) is a universal preservative for a number of foods (fruits, meat, eggs, etc.). Especially strong bactericidal action of benzoic acid and its compounds are in environments with a low content of nitrogenous substances and with a clearly pronounced acid reaction. The most suitable for preserving it are products that have a pH in the range of 2,5 — 3,5. Benzoic acid has a preservative effect, mainly directed against yeast. From this it follows that it is suitable as a preservative for applesauce, since the latter has a relatively high acidity and a low content of nitrogenous substances. The dosage of benzoic acid necessary for canning mashed potatoes can vary within 0,05 — 0,10% depending on the natural acidity (pH) of applesauce: when working with strongly acid mashed potatoes, you can take the maximum dosage of preservative and vice versa.
Benzoic acid and its compounds puree to give a light sugary tart flavor. When canning within dosages not exceeding 0,1%, this taste of benzoic acid is not felt.
Benzoic acid is poisonous, but, getting into a human body in small doses, it does not linger in it. Reacting with the glycol, it turns into hippuric acid in the body
This reaction develops in kidneys where a preservative as hippuric acid excreted.
The marginal rate for the content of benzoic acid in finished products of marmalade-pastille production according to the establishment of the Scientific Medical Council of the Ministry of Health of Ukraine is 0,07%. For applesauce, this rate is 0,10%.
Benzoic acid and its compounds are of low volatility, which makes it possible to use them for preserving mashed potatoes, both hot and cold, in non-hermetic equipment.
Due to the poor solubility of benzoic acid in water are usually used for preserving its mashed soluble sodium salt (sodium benzoate) or an ammonium salt (ammonium benzoate). The sour mash, which is available a sufficient number of free acid stronger than benzoic acid, the latter is released from the benzoate.
If applesauce is slightly acidic, then when canned with sodium benzoate, there is sometimes some darkening of the mashed potatoes. When this occurs, the neutralization of part of the acid and a noticeable shift in pH, which is undesirable for gelation, taste and durability of the puree. In these cases, the use of free benzoic acid or artificial acidification of mashed potatoes with edible acid is more useful.
To enhance the action of benzoic acid against mold, it is sometimes used in a mixture with food acids or with sulfuric acid. Benzoic acid is often used in the form of its esters or mixtures of benzoic acid and its derivatives, which have a high bactericidal effect. These drugs are known abroad under the name "microbin" (sodium chlorobenzoic acid salt C6Н4S1SOShe, “Nipacombin” (a mixture of 2 parts of ethyl ester of benzoic acid and 4 parts of propyl ester of the same acid), etc. There are preparations that represent combinations of benzoic and sulfuric acids.
Technology preservation sodium benzoate is as follows.
Prepare 10% or 20% solution of the benzoin sodium salt in hot (70 — 80 °) water. The solution is filtered or filtered and then added to the hot puree and stirred with it using a mechanical stirrer or manually. It is important that at the same time a uniform distribution of the preservative over the whole mass of mashed potatoes was achieved. The amount of preservative solution is taken from the appropriate calculation in order to ensure the concentration of benzoic acid in the puree within 0,07 — 0,10%.
When using free benzoic acid, it is necessary to convert the latter to sodium benzoate by treating with soda. To convert benzoic acid to sodium salt, use bicarbonate soda. It is necessary to take chemically pure preparations with a known content of C6Н5SOON i Nansi3 by the reaction equation:
Sulfurous acid H2S03 is a stronger preservative than benzoic acid. It exerts its bactericidal effect on both yeast and molds. Due to its regenerating effect, sulfurous acid contributes to the preservation of the color and anti-scorching properties of the conserved puree.
With these positive properties, sulfurous acid is more harmful to humans than benzoic acid, since it is a cumulative poison that accumulates in the body as it is consumed. In this regard, sanitary legislation strictly limits the limits of permissible residual content of this preservative in finished products. According to the sanitary regulations that we have, this standard is not limited to 20 mg (in terms of free S02) And not higher 100 mg total S02 on 1 kg jellies and pastes, t. e., respectively, in the range of up to 0,002 0,01% and% to the weight of the finished product.
Cooking ready-made confectionery products from semi-finished products is usually accompanied by the removal of sulfurous anhydride. Sulfonated puree, in particular in the production of marshmallow, is subjected to pre-desulfurization before churning it with sugar.
The disadvantages of sulfurous acid as a preservative are that it is fragile and volatile. During long-term storage of mashed potatoes, preserved with sulfuric acid, the latter part is oxidized to sulfuric acid, while in other parts it forms other sulfur compounds when interacting with sugars and other organic substances of mashed potatoes. Due to this, the preservative effect of sulfurous acid decreases over time. The weakening of the action of sulfurous acid is also possible due to the volatilization of part of it during storage through the leakage of the container. Due to its volatility and partial release in the processes of canning, secondary wiping and churning, sulfur dioxide significantly worsens working conditions.
A disadvantage of sulfurous acid as a preservative is the fact that it causes corrosion of metal parts of the apparatus.
Despite the indicated negative properties of sulfurous acid, it is allowed for the preservation of fruit and berry puree in the absence of other preservatives. In the presence of benzoic acid and its preparations, it is necessary to use them predominantly.
For canning fruit puree, sulfurous acid is used in the form of 6 — 7% aqueous solution or 100% bottled gas. The calculation of the required amount of preservative is based on the amount of puree, the concentration of the working solution of sulfurous acid and the dosage of 0,10 — 0,12% $ 0? by weight mashed. Usually take the solution in a slightly larger amount, taking into account the possible loss of B02 due to volatilization. Sulfurous anhydride is metered directly from the cylinders according to the change in the net weight of the balloon put on the scales.
Sulfur dioxide is one of the gases whose solubility decreases strongly with increasing temperature. In this regard, it is usually provided mandatory cooling fruit and berry puree before the introduction of sulfurous acid.
Special cooling devices provide the ability to quickly and rapidly cool the mashed potatoes to a temperature of 10 — 15 °, i.e., to a temperature that does not pose a danger to the development of yeast in it.
The VKNII study  was theoretically substantiated and the possibility of preserving apple saute in hot condition with sulfuric acid without pre-cooling the latter was practically tested.
These solubility S02 show that the saturation concentration S02 in water at 100 ° it is about 0,1%, i.e. it corresponds to the dosage of S02adopted for canning mashed potatoes. In connection with the adsorption capacity of pectin substances and other colloids that make up the mashed potatoes, it can be expected that the amount of 302 held in mashed potatoes at high temperatures will be higher than in pure water.
In accordance with Henry-Dalton's law, the solubility of sulfur dioxide in hot mash can be greatly increased by increasing the partial pressure of S02 in space above the surface of preserved mashed potatoes. In practice, this condition is carried out by dissolving and stirring hot mashed potatoes with S0.2 in hermetically sealed faucets. Good results in terms of minimal preservative losses are obtained if you mix hot mashed potatoes with preservatives at temperatures no higher than 70 — 75 °.
In order to better preserve the gelatinous ability of the puree in the process of sulfitation, it is advisable to cool it beforehand to 50 — 55 °.
The process of pre-cooling the apple puree and its subsequent sulphitation in a hermetic apparatus is carried out in a continuously operating system of the Krasnodar branch of the Central Research Institute of the Canning Industry (Fig. 8).
The device consists of a vacuum receiver 1, which serves to pre-cool the mashed potatoes. The latter is continuously sucked inside the vacuum receiver, in which 500 — 600 mm Hg vacuum is maintained. Art. At the same time, the puree is cooled to 55 60 ° and is somewhat thickened due to self-evaporation. —2. In the sulfitator, the puree is saturated with sulfuric anhydride and the mixture is further cooled to 7 - 4 °. Sulfur dioxide is supplied to the sulfitator as 5%. S02, T. E directly from the cylinder through the 6 3 reducing valve.
Fig. 8. Continuously operating plant for canning fruit and berry puree.
With the help of the latter, the gas supply to the sulfitator is regulated in such a way that it comes with a pressure of approximately 0,4 — 0,5 ati and so that when mixing gas with puree for about two minutes, the content of S02 in the mixture was 0,12 — 0,15%. The canned mash is continuously exited from the machine through the 10 pipe through the purse that feeds it to storage tanks or barrels for transportation.
All parts of the plant in contact with mashed potatoes and S02They are made of anti-corrosion materials.
Plant capacity of about 2 t / h on applesauce.
In small enterprises, for this purpose they use hermetic periodic-effect sulphidizers constructed according to the same principle, in which they preserve in the form of bottled gas or in the form of 6 — 7% aqueous solution.
In the latter case, there is some dilution of the mash water, which is undesirable, and therefore it is preferred to use sulfur dioxide dosed directly from cylinders.
Work with S02 should be carried out as far as possible under sheds, i.e., in the open air, or in rooms equipped with special ventilation.
Workers who come into contact directly with a preservative (who make the working solution S02, care for gas cylinders, etc.) should use gas masks.
Canned mashed potatoes, poured into storage tanks, should be immediately, as they are filled, hermetically sealed, filled barrels - immediately sealed.
Recently, for preserving fruit and berry puree, some new preservatives have been proposed, from which propionic, sorbic acids and their compounds should be mentioned.
Of great interest in this regard is the unsaturated fatty acid series - sorbic acid CH3—CH = CH — CH = CH — COOH. There are a number of reports that it reliably protects many food environments, including fruit and berry puree from fermentation and molding. It is more effective as a preservative than benzoic acid and does not impart an off-flavor product. The required dosage for fruit puree is about 0,05%. According to reports, it is completely harmless; its disadvantage is poor solubility in water. Therefore, it is practiced to use it in a solution of propylene glycol at a concentration of about 5%.
Storage applesauce in transport and stationary containers
Enterprises producing marmalade-pastila should have in store for long-term storage of prepared fruit and berry semi-finished products (applesauce, sulphite fruit, etc.).
Storage of fruit and berry semi-finished products is an important stage of the technological process in this production.
Canned apple puree, intended for storage or for shipment, is poured into barrels with a capacity from 100 to 200 l. The quality of the barrels is of paramount importance. They must fully comply with current specifications.
Before filling, the barrels must be carefully prepared. For this purpose, they are pre-soaked in water so that the dirt that has dried on them gets wet, and also that the rivets swell and become compacted in the seams. After soaking it is necessary to wash the barrels with the help of special machines that wash them outside and inside.
Then proshparivayut steam drums.
New, previously used barrels, especially oak barrels, must be pretreated with 3 — 5% soda solution to extract tannins from the wood that could cause the mash to darken. After treatment with soda, the barrel is washed several times with clean cold water until all traces of alkali are completely removed.
Old barrels not been processed with alkali, sulfur should be fumigated after scalding.
Proper preparation of the barrels to receive mashed potatoes ensures the destruction of foci of infection in them that can lead to contamination and deterioration of mashed potatoes.
Barrels are filled approximately on their height 0,9, around 1 / 10 the capacity of the barrel usually remains empty, which creates reserve space in the barrel in case of mash expansion due to obstruction, warming or freezing.
Barrels of applesauce, canned sulphurous anhydride, immediately clog at a temperature of mashed potatoes not higher than 55 — 60 °.
If the mash is conserved by benzoic acid, then its temperature at the time of capping the barrels should be no higher than 45 — 50 °, since at a higher temperature some darkening of the mash is possible.
After capping the drums with mashed potatoes, they are held until shipped within 3 — 4 days under special supervision in the coldest place possible. The purpose of this excerpt is to identify simultaneously with the course of cooling mashed potatoes with defects or with unstable mashed potatoes.
The product of fermentation with signs or dokonservirovat necessary to resort to recycling.
After this test, the barrels are finally sealed and the hoops are fixed on them. On the upper bottom of the barrel is labeled in accordance with the requirements of the standard.
Apple puree is stored in warehouses, isolated from the influence of external atmospheric conditions. The optimal storage temperature is 1 — 2 °.
The freezing of apple puree is undesirable, since it necessitates a special thawing of the puree before it is put into production. The most favorable relative humidity of air 70 — 80%.
The barrels are stacked in piles flat on 2, 3, 4, 5 rows horizontally or upright in the 2 — 3 tier vertically. Laying the barrels in tiers and dismantling the tiers is facilitated when using special mechanical devices for lifting the barrels and reassembling the tiers of the barrels with wooden planks. In these cases, the barrel with mashed potatoes can be stacked higher than in the 2 — 3 tier.
Between piles or rows in which individual batches of mashed potatoes are stacked, as well as along walls, passages with a width of about 0,75 m are left.
The required area under the given conditions (laying in the 2 — 3 tier) on the 1 and mash is 1,3 — 1,6 and m2.
Before laying in piles, each barrel of mash should be subjected to a thorough visual inspection.
Special monitoring of the hermetic sealing of the drums and the removal of any mashed potatoes from the warehouse is necessary. It is important in order to control pest puree. Of these, the most common is the so-called acetic fly, or the red fly (Drosophilla cellaris). It lays its larvae in mashed potatoes and, in addition, is a carrier of yeast and acetic acid bacteria.
In winter, apples are allowed to be stored in the courtyard. However, the apple puree frozen during the winter after thawing should not be left for storage in warm conditions, since the multiplication of microorganisms in thawed products is more intense than in products that have not been subjected to freezing.
In the warm season, open storage of applesauce is unacceptable.
In the absence of storage, storage of applesauce in barrels in the open air is possible in piles, provided that stacks are laid in winter in the snow or in ice and the entire collar is covered with an insulating layer to prevent the collar from warming up for the entire storage period. This method of storage guarantees almost completely from losses / valuable product due to the  perebrod and can be recommended for confectionery factories, and especially for jelly pastry shops in the regions of the northern and temperate regions of Ukraine.
To ensure the preservation of purée from perebrod, it should be stored for a long time, it should contain at least 0,12 — 0,15% sulfur dioxide and sodium benzoate acid at least 0,1% by weight mash.
With proper storage of canned applesauce in strong barrels, losses from leakage, drying or perebroda do not occur. However, in all circumstances there are known losses from the absorption of extractive substances mashed wood barrels. According to VKNII , these losses from soaking in small barrels with a capacity of 100, l make up 0,4% by weight of mashed potatoes or about 4% by weight of dry substances of mashed potatoes.
In this regard, the application of insulating coatings (paraffin, bakelite, enamel, varnishes) on the inner surface of the barrels is of great importance. Usually used for this purpose waxing them. In this case, molten paraffin is applied on the inner surface with a thin layer that covers the pores of the wood.
Preparation, filling, capping and dismantling of small barrels (capacity 100 — 200 kg) require a considerable expenditure of labor. In view of this, with large production and consumption of applesauce, it is advisable to organize its storage in large tanks. On the inner surface of them must be coated, indifferent chemically to the puree. Such tanks are widely used in fruit-processing enterprises of the canning industry. Storage of mashed potatoes in large volumes is combined with mechanical pumping and non-working (bulk) transportation of it. This drastically reduces the cost of packaging and its depreciation, reduces the loss of mashed potatoes during storage, reduces the storage area, reduces the cost of servicing mashed storage.
When storing the apple (puree, it is necessary to make observations on the change in the content of dry substances in it. These observations should be accompanied by the control of the content of microorganisms and preservative in the puree.
Driving line production of fresh apple puree
Production of apple puree in large confectionery factories implemented in the form of production lines.
Below is a brief description of the production line for apple puree production at the Nalchik Confectionery Factory (Fig. 9). It provides for apple scrambled in Dmitriev's vaporizer and canning mashed potatoes S02 by setting the Krasnodar branch of the Central Research Institute of the canning industry.
Apples are unloaded from 1 drawers, weighed with 2 scales. They are then transferred to the inspection conveyor 3, on which the marriage is separated. Sorted apples are pre-washed in an 4 elevator car wash and then in a 5 ventilator car wash. The washed apples are lifted by the 6 Elevator to the 7 evaporator. The apples are discharged from the bottom of the vaporizer to the 10 cleaning machine, and the condensate and drain from the vaporizer are collected in an 8 collector for use. Shredded apples pass before rubbing through the 9 roller crusher for pre-grinding (the crusher rolls are arranged so as to avoid crushing the seeds). Wiping mash flows into an open 11 collector, from where it is sucked into the 12 vacuum receiver. From it, the puree is pumped out by the 13 plunger pump into the 14 sulfitator, from which it continuously enters the storage tanks or is packaged in barrels.
Fig. 9. Driving line production puree from fresh apples.