Prevention of microbiological defects in sauerkraut and vegetable salting technology

Microbiological defects in sauerkraut fermentation

bacteria and promote the development of a fungus that releases melanins, colored brown or black. Sometimes the blackening of cabbage can be associated with a high iron content, which reacts with tannin present in the wood of the vat or the weighted lid, forming dark-colored sulfides.

Reddening — the staining of cabbage in a pink color is caused by yeast of genera that form carotenoids — substances that give the product a pink or coral, red color. High salt concentration and the presence of oxygen promote the development of yeast of this genus.

Creamy, white, and green films are formed by bacteria and species of fungi of the genus The latter cause green staining of the cabbage. However, films only form during gross violations of the technology.

Flabbiness (loss of crunch) — this defect is determined by a lack of salt and a high fermentation temperature, which disrupts the sequence of lactic acid bacteria development, as well as by oxygen access, which promotes the development of aerobic bacteria and fungi that release cellulose-destroying and pectolytic enzymes.

Sliminess of cabbage is observed when bacteria convert sucrose into dextran. Mucilaginous substances from carbohydrates can also be formed by species of the genus

Rancidity occurs during the delay of lactic acid fermentation. Due to strongly elevated or lowered temperatures, butyric acid bacteria can develop in the cabbage, giving the cabbage a sharp rancid taste and a pungent unpleasant odor. Along with this, gaseous products are formed. This defect develops during gross violations of technology.

Sometimes psychrophilic bacteria, which can develop at temperatures below 5°C, also give the cabbage a bitter taste. Bitterness can be caused by magnesium sulfate (Epsom salt), so it is necessary to use common salt of at least the first grade.

Technology of pickling cucumbers and tomatoes

Fresh and healthy cucumbers, harvested while still green, are used for pickling. For salting, we take cucumber cultivars grown in open soil with firm flesh, non-coarse skin, and a small seed cavity — preferably no more than 25% of the fruit volume.

Freshly harvested cucumbers are sorted by size:

• gherkins: 3–5 cm in length;
• cornichons 1st group: 5.1–7 cm;
• cornichons 2nd group: 7.1–9 cm (used for marinating);
• green pickling cucumbers: from 9 to 14 cm (small 9–11 cm, medium 11–12 cm, and large 12–14 cm) — they are used for barrel salting together with spices.

During salting, the cucumber flesh is saturated with brine, with the simultaneous release of sugar and other substances from the cells into the brine. Therefore, it is very important to use sugary cucumbers with firm, fleshy pulp and tender warty skin for salting.

Collected cucumbers must be subjected to salting as quickly as possible, because during storage, especially at high temperatures, they become limp, lose sugar, and overripen, which ultimately makes them unsuitable for salting.

Cucumber salting technology: Cucumber salting is carried out in barrels with a capacity of no more than 100-150 kg. In containers of larger capacity (vats), the salted cucumbers lose quality, over-acidify, become hollow, and get crushed. Barrels for salting cucumbers are washed in advance and treated with steam and sulfur dioxide.

For salting, batches of cucumbers of the same botanical cultivar are taken and calibrated. Sorting and calibration are carried out manually.

Preparation of cucumbers for salting consists of sorting and washing them. During sorting, all diseased, limp, mechanically damaged, and overripe cucumbers are removed, and the suitable ones are calibrated, i.e., sorted by size so that cucumbers of the same size are packed into a separate barrel.

Simultaneously with the preparation of containers (barrels) and cucumbers, spices are prepared. The following are used as spices when salting cucumbers: dill, horseradish, garlic, pepper, tarragon, parsley, celery, and black currant or cherry leaves. The spices must be fresh and prepared immediately before placing them into the barrel. They improve the taste of the cucumbers, and some of them prevent the development of harmful microorganisms.

When salting cucumbers, the following spices are mandatory: garlic, horseradish (root or leaves), and hot chili (red) pepper. When salting in barrels made of soft wood, oak or black currant leaves must be added.

When salting cucumbers, spices are added based on the mass of the cucumbers: 3-4% - dill, 0.5-0.8% - horseradish root, 0.3-0.4% - garlic, 0.1-0.15% - fresh hot pepper, etc.

The spices are washed and laid evenly into the barrels, layering them with the cucumbers. After this, the contents of the barrels are poured over with a salt solution. It is better to use coarse-grained rock (common) salt for salting. Impurities of calcium salts increase water hardness. To prepare the common salt solution, clean drinking water with a high content of calcium salts is used, which ensures the crunchy consistency of the cucumbers. The water should have between 20 and 35 mg eq/l. The concentration of the salt solution for large cucumbers is 7%, for small and medium ones — 6%.

After pouring the salt solution over the cucumbers, they are kept for 1-2 days in fermentation areas, then the salt solution is topped up, the bunghole of the barrel is sealed, and they are sent for storage in icehouses, refrigerators, or cellars.

Salted cucumbers should have a pleasant aroma and taste, a crunchy consistency, and firm flesh.

The brine should also be aromatic, free from mold and musty odors, and not viscous. The salt content in the cucumbers should be 2.5-3%, and acids 0.6-1.2%.

Softening of cucumbers (loss of crunch) — the most likely cause of this defect is considered to be the enzymatic breakdown of pectin and cellulose-containing compounds in the cucumbers. Enzymes can be of microbial origin (bacterial, yeast, or fungal genera) or plant origin.

Hollow cucumbers ("bloaters") — swelling of the cucumbers and the formation of cavities are caused by yeasts, representatives of Enterobacteriaceae, and heterofermentative lactic acid bacteria. This defect appears when using overripe and long-stored cucumbers with tough skins that prevent gas escape. It can be prevented by pricking the cucumbers before salting.

Formation of a film on the brine surface — film appears under aerobic conditions at various times after the main fermentation stage has passed. It consists primarily of film-forming yeasts of the genera. Molds and species of other genera can also develop in the film. The film-forming microorganisms consume lactic acid and sugar, which enter the brine from the cucumbers. The development of the film is suppressed by anaerobic conditions, low temperatures, and the addition of mustard oil, cinnamon, or garlic. The use of sorbic acid is effective. If the film is not removed, the cucumbers may develop an unpleasant odor and taste.

Technology of salting tomatoes: Preserving tomatoes using this method allows them to be kept throughout the winter until the new harvest. Salted tomatoes retain ascorbic acids and carotene well.

For salting, it is best to use medium-sized brown, pink, and red tomatoes; these fruits are sufficiently delicate yet firm. The best choices are meaty, firm-fleshed, and sugary cultivars. Before salting, the fruits are sorted, removing mechanically damaged or diseased fruits, and separating them into batches uniform in maturity and size.

Preparation of containers, spices, and brine, and packing are carried out just as for salting cucumbers. The washing and sorting of fruits by quality and size are also performed just as thoroughly. For salting, barrels or 3-10 liter glass jars are used. When salting tomatoes, they must be placed carefully into the container.

When salting green tomatoes, they are subjected to blanching in boiling water for 1 minute; the washed tomatoes, placed in baskets, are submerged in vats of boiling water.

During blanching, the skin of the tomatoes is scalded, which subsequently facilitates better penetration of the brine into the tissues. To avoid the tomatoes becoming overcooked during blanching, they are immediately placed in cold water after spending one minute in boiling water.

The brine concentration depends on the degree of fruit maturity and storage conditions. When stored on ice, the brine concentration should be 6-7% for red tomatoes, 7-8% for brown, and 8% for green. When stored in non-refrigerated warehouses, the brine concentration increases to 10%.

Provide a description of cabbage fermentation technology?

Provide a description of cucumber salting technology?

Provide a description of tomato salting technology?

Determine the loss of grain mass during the drying of 1000 tons of food wheat with a decrease in moisture content from 26% to 14%. Calculate the volume of work in standard drying units and the drying time using the SZSh-16 shaft dryer?

The loss of grain mass during drying X, %, is calculated using formula (1):

where a is the grain moisture before drying, %;

Table 4 - Volume of work in standard drying units (Trisvyatsky L.

Throughput Moisture Mass of grain, t Conversion Quantity Drying removal, % factor of time, before after units h

1 26-20 1000 925 0.88 880 55

2 20-14 925 861 1.00 925 58 Total 12 1000 861 — 1805 113

Determine the loss of wheat grain in a typical storage facility given the volume and duration of storage in the example?

For individual months, wheat grain was received and expended in the warehouse in the following quantities:

Table 5 - Receipt and expenditure of wheat grain (Trisvyatsky L.

Receipt Expenditure Grain on first Months mass, kg weed mass, kg weed day impurity, impurity, % %

1 2 3 4 5 6 7 8 August 100500 15 1 - 100500 September 200350 16 0.5 - 300850 October - - - - 300850 November 199150 15 1 - 500000 December - - - - 500000 January - - - 105000 14 1 395000 February - - - 4500 15 1 390500 March - - - - 390500 April - - - - 390500 May - - - - 390500 June - - - - 390500 July - - - 300000 15 0.5 90500 August - - - 85000 14 0.7 - Total 500000 494500 4140200

Upon re-weighing the grain, a shortage of 5500 kg was discovered.

Decrease in moisture content and the amount of weed impurity.

a) Determination of weighted average humidity by intake, (%)

100500 kg X 15% =1507500 kg %

200350 kg X 16% =3205600 kg %

199150 kg X 15% =2987250 kg %

7700350 kg % / 500000 kg = 15.4 % b) Determination of weighted average humidity by expenditure, (%)

105000 kg X 14 % = 1470000 kg %

4500 kg X 15 % = 67500 kg %

300000 kg X 15 % = 4500000 kg %

85000 kg X 14% = 1190000 kg %

7227500 kg %/ 494500 kg = 14.6 % c) Determination of weighted average weed impurities by intake, (%)

100500 kg X 1 % = 100500 kg %

200350 kg X0.5 %= 100175 kg %

199150 kg X 1 % = 199150 kg%

399825 kg %/ 500000 kg = 0.80% d) Determination of weighted average weed impurities by expenditure, (%)

105000 kg X 1 % = 105000 kg %

4500 kg X 1 % = 4500 kg %

300000 kg X0.5 % = 150000 kg %

85000 kg X0.7% = 5900 kg %

319000 kg %/ 494500 kg = 0.65%

Table 6 - Weighted average humidity and weed impurities, kg/% (2x3) 1. 1507500 1470000 100500 105000 2. 3205600 67500 100175 4500 3. 2987250 4500000 199150 150000 4. - 1190000 - 59500 Total 7700350 7227500 399825 319000 Weighted average 15.4 14.6 0.80 0.65

2. Mass loss due to reduction in humidity and weed impurities

Determination of mass loss Xi due to reduction in humidity is calculated using formula (1):

where a - weighted average humidity by intake, %;

Xi =100х(15.4%- 14.6 %) /10014.6 % = 77% / 85.37 % = 0.90 %

500000 kg X0.90 %/100% = 4500 kg

Determination of grain mass loss Xg from the reduction of weed impurities. Beyond the grain written off according to processing certificates, it is determined by formula (2) where b - weighted average weed impurities by intake, % c - weighted average weed impurities by expenditure, %

Xi - mass loss due to reduction in humidity, %

Xg= (0.8% - 0.65 %) х(1000.90 %) / 100-0.65 % = 0.15%

500000 kg X0.15 %/ 100% = 750 kg

4500 kg + 750 kg = 5250 kg

Grain mass loss due to change in humidity 0.90% (4500 kg) Grain mass loss due to change in weed impurities 0.15% (750 kg)

A shortage of 250 kg remains, which is not caused by the change in grain quality.

Determination of the average storage period of a grain batch

The average storage period (C) is determined by dividing the sum of monthly balances by the grain mass by intake using formula (3) where C - average storage period, month

I - total grain balance on the first day of each month, kg

C = 4140200 kg / 500 000 kg = 8.29 = 8.3 months

Average storage period of the grain batch is 8.3 months.

4. Determination of the natural loss rate for the average storage period.

If the average storage period falls within the limit of up to 3 months, it is determined by formula (4) a - loss rate for up to 3 months, %

The average grain storage period in the considered example - 8.3 months is determined by formula (5)

X —a -\- (5) where X - natural loss rate, % a - natural loss rate for the previous storage period, b - difference between the highest rate for the given intermediate c - difference between the average storage period of this batch and the period, d - number of months, storage to which the difference refers between

X = 0.09% + ((0.03%х 2.3)/ 6) = 0.101 %

X = 494500 kg X0.101 %/100 % = 499.44 kg

Natural loss rate for the average storage period is 499.44 kg.

Thus, due to the reduction in humidity and weed impurities, one can write off 4500 kg + 750 kg = 5250, due to natural loss 499.4 kg, that is, a total of 5250 kg + 499.4 kg = 5750 kg is subject to write-off.

Shortage according to the table is 5500 kg, although losses of 5750 kg are acceptable according to calculations, THEREFORE, THERE ARE NO UNJUSTIFIED LOSSES

Determine the estimated and actual product yield for baking two-grade 75% wheat milling with base yields: 40% top grade, 35% 1st grade, 22.1% bran.

Quality indicators of processed grain, % (before cleaning):

of 1st grade flour - 660 000;

Weighted average humidity of top-grade flour - 14.5%, 1st grade -

From the initial quality indicators, humidity, vitreousness, test weight, weed and grain impurities will affect the finished product yield.

When calculating the yields of high-grade wheat flour depending on humidity, the calculated moistening (shrinkage) is determined based on the initial humidity of the processed grain and the adopted weighted average humidity of the product.

2)x 100/(100-Vg),

Vg - adopted calculated humidity of the product, (14.5%).

X =(13.28-14.5) X 100/(10014.5) = - 1.43%

The allowance (with a plus sign) to the total yield of flour and bran is made at a rate of 0.5% for each percent of calculated moistening (appendix 11), which is: 0.5 х 1.43 = 0.71%. The shrinkage value is reduced by the same amount (0.71%).

If the humidity of the initial grain is lower than 12%, then when determining the calculated product yield, it is equated to 12%.

The allowance value (0.71%) accounts for 97.1% of the flour and bran yield, including:

for top grade 0.71%х40%/97.1% = 0.29 %;

for first grade 0.71%х35%/97.1% = 0.26 %;

for bran 0.71%х22.1%/97.1% = 0.16 %;

Vitreousness is 45%, which is lower than the base (50%) by 5%.

For each percent of total soft wheat vitreousness below the base, the flour yield rate decreases by 0.05% (appendix 11), the bran yield increases by the same amount, the discount size (minus) on flour yield:

(50-45)х0.05 = 0.25% for top grade 0.25%х40%/ 75% = 0.13 %, for first grade 0.25% х 35%/ 75% = 0.12% allowance size (plus) to bran yield - 0.25%.

For each gram of test weight less than 775 g/l for wheat, the discount on the flour yield rate is 0.05% with a corresponding allowance on bran yield.

Discount size (minus) on flour yield (775g/l - 760g/l) X 0.05% = 0.75%, for top grade 0.75% х40%/ 75% = 0.40 %, for first grade 0.75% х35% / 75 % = 0.35%.

Allowance (plus) for bran yield 0.75%.

For every percent of weed impurity above the base (1%), the standard yield of flour and bran is reduced by 1% due to an increase in the yield of feed grain product.

The content of weed impurity is 1.38%, i.e., higher than the base by 1.38% - 1.00% = 0.38%.

Discount amount (minus) from the yield of flour and bran

0.38% X 1.00% = 0.38%.

for the superior grade 0.38% x 40% / 97.1% = 0.16%, for the first grade 0.38% x 35% / 97.1% = 0.13%.

for bran 0.38% X 22.1% / 97.1% = 0.09%.

Allowance (plus) for the yield of feed grain product 0.38%.

Based on the content of grain impurity and small grain

For every percent of total grain impurity above the base (1%) and small grain, there is a discount from the yield of flour and bran of 0.35% with a corresponding increase in the feed grain product.

2. For every percent of total grain impurity above the base (1%) and small grain, there is a discount from the flour yield of 0.18% with a corresponding increase in the bran yield.

According to the task, the grain impurity is 3.0%, i.e., 2.0% above the base, and the content of small grain according to the task is 1.1%.

Discount amount (minus) from the yield of flour and bran (3.0% - 1.0% + 1.1%) X 0.35 = 1.09% for the superior grade 1.09% x 40% / 97.1% = 0.45%, for the first grade 1.09% x 35% / 97.1% = 0.39%.

for bran 1.09% x 22.1% / 97.1% = 0.25%.

The yield of feed grain product increases by 1.09%.

Discount amount (minus) from the flour yield (3.0% - 1.0% + 1.1%) X 0.18 = 0.56% for the superior grade 0.56% x 40% / 97.1% = 0.30%, for the first grade 0.56% x 35% / 97.1% = 0.26%.

The bran yield increases by 0.56%.

The obtained discount and allowance values are entered into the clearing report (act) form No. ZPP-117 and summed up for each product type: first all deviations with a plus sign (allowance), then with a minus sign (discount). Then, the smaller sum is subtracted from the larger sum, and the sign of the larger value is assigned.

From the table of form No. ZPP-117, it is evident:

How the calculated yield of superior grade flour is determined, ((-0.13%) + (-0.40%) + (-0.16%) + (-0.45%) + (-0.30%)) = -1.44%;

the total discount value exceeds the allowance value

-1.44% + 0.29% = -1.15%.

The standard of calculated yield for superior grade flour is

Also, the calculated yield for the first grade flour is determined:

((-0.12%) + (-0.35%) + (-0.13%) + (-0.39%) + (-0.26%)) = -1.25%;

the total discount value exceeds the allowance value

-1.25% + 0.26% = -0.99%.

The standard of calculated yield for first grade flour is

35.0% - 0.99% = 34.01%.

allowance ((+0.16%) + (+0.25%) + (0.75%) + (+0.56)) = +1.72%;

discount ((-0.09%) + (-0.25%)) = -0.34%;

the total allowance value exceeds the discount value

+1.72% - 0.34% = +1.38%.

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Standard of calculated bran yield: 22.1% + 1.38% = 23.48%.

allowance ((+0.38%) + (+1.09%)) = +1.47%.

2.20% + 1.47% = 3.67%.

For waste: 0.70%. For shrinkage: -0.71%.

The accuracy of the calculation is verified as follows: the sum of deviations for one quality indicator, taken across all products, must be equal to zero.

Thus, when calculating by the humidity indicator, the total flour yield increases by +0.55% (+0.29% superior grade and +0.26% 1st grade), bran yield by +0.16%, and shrinkage is equal to (-0.71%). Consequently, +0.55% + 0.16% - 0.71% = 0%, i.e., the sum of allowances is always equal to the sum of discounts.

To verify the accuracy of the full calculation, it is necessary to add up the obtained yield values of various product types.

The calculation is correct if the algebraic sum is 100%, as in the provided example:

38.85% (superior grade) + 34.01% (1st grade) + 23.48% (bran) + 3.67% (feed grain product) + 0.70% (waste and mechanical losses) + (- 0.71%) shrinkage = 100%.

In form No. ZPP-117, the calculated yield of products is expressed in % and kg.

In this example, when processing 2,000,000 kg of grain, the calculated yield should be (in kg):

waste and mechanical losses 14,000.

In order to calculate the actual yield of products (%), as well as the actual shrinkage (or humidification) and mechanical losses (for a certain period of time), it is necessary to have the following data: the quantity of processed grain; the quantity of produced flour (by grades), semolina, bran, feed grain product, waste; the weighted average humidity of the products and the grain that entered the grain cleaning department.

In the example, when processing 2,000,000 kg of grain, the following was obtained (kg):

superior grade flour 820,000 x 100 / 2,000,000 = 41.0%;

first grade flour 660,000 x 100 / 2,000,000 = 33.0%;

bran 470,000 x 100 / 2,000,000 = 23.5% feed grain product 59,800 x 100 / 2,000,000 = 2.99%.

After this, the size of the actual shrinkage or humidification is determined.

When calculating the actual shrinkage (humidification), the actual humidity values of the initial grain and finished products are used. To determine the actual weighted average humidity of the products (semolina, flour, and bran), it is necessary to divide the sum of ton-percentages by the total weight of the produced products.

Havg = 11.5% x 820 t + 14.4% x 660 t + 13.8% x 470 t / 1950 t = 14.3%.

Since the weighted average soil moisture of grain before cleaning Bi = 13.28%, and the weighted average humidity of the product Вг = 14.3%, therefore the actual moisture content (X):