RU2555546C2 - Pasteurised drinking milk preservation method - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: invention relates to dairy industry. The method involves introduction of a preserving agent (represented by cupric sulphate in a dose of 2.0-2.5 mg/dm³ and 0.6-0.8 mg/dm³ of potassium iodide or 1%-solution of Trilon B) into pasteurised drinking milk under slight stirring conditions and preservation at a temperature of 4±2°C.

EFFECT: invention allows to increase milk preservation term ensuring optimal acidity.

1 tbl, 1 ex

Description

The invention relates to the dairy industry and can be used for the preservation of milk.

When purchasing, cow's milk must satisfy a number of requirements, including titratable acidity, purity and bacterial contamination.

High-quality milk (premium, first grade, second grade) should have an acidity of 16 ... 21 ° T, a uniform consistency, without sediment and flakes, white or light cream in color, without odors and flavors not characteristic of fresh natural milk. Fresh milk is protected by mammalian biology against rapid souring (several hours depending on air temperature and degree of contamination). Over time, due to the work of lactic acid bacteria, it is acidified (acidity), milk can clot. To extend the shelf life, it is usually cooled and pasteurized [1, 2, 3].

Drinking milk is packaged in consumer packaging after heat treatment and can be intended for use in food, has an acidity of 20 ... 21 ° T. Storage conditions and expiration dates are set by the manufacturer [4].

Raw milk has a shelf life of up to 36 hours. To extend the shelf life, there are various methods of preserving milk.

A known method of preserving milk, including the introduction of a preservative - sulfur dioxide - gas [5]. Gas sparging is carried out until the pH of the milk reaches 6.0. The disadvantage of this method is the use of environmentally hazardous substances SO ₂ .

A method of preserving milk is described by adding 105 mg of silver complex compound per 1000 kg of milk before pasteurization in order to increase the shelf life [6]. The method involves the use of an expensive chemical preservative.

A known method in which milk is processed in a diaphragmless electrolyzer with graphite electrodes with a milk flow rate of 300 l / h at a current strength of 15 A, a temperature of 26 ° C. The acidity of milk decreased by one degree Turner (from 17.5 to 16.5 ° T) while maintaining other quality indicators.

A method is described for preserving milk by introducing into it a preparation containing complex compounds of silver and copper with aminoacetic acid (silver glycinate and copper glycinate) in the form of a solution with a concentration of silver and copper ions below their maximum permissible concentrations (MPC). The solution was administered in an amount of 1 ml per 1000 ml of milk. The ratio of ion concentration was 0.017-0.034 mg of Ag ⁺ / dm ³ and 0.67-0.32 mg of Cu ²⁺ / dm ³ . After the introduction of these substances, pasteurization was carried out at a temperature of 76 ± 2 ° C with an exposure of 20 s. The acidity of milk did not exceed 18.5 ° T; milk was stored at a temperature of + 2 ... + 4 ° C for 5-6 days. No other quality indicators are reported.

The disadvantage of this method is the complexity of the technology of preparation of a preservative using a noble metal (silver) [7].

A known method of preserving milk, mainly for the preservation of skim milk (prototype).

The method was carried out as follows. In 1 ton of freshly obtained cooled skim milk with an acidity of 18 ... 20 ° T, solutions of hydrogen peroxide in the amount of 0.05 ... 0.1% and potassium iodide in the amount of 0.00025 ... 0.001% were introduced successively with constant stirring. Hydrogen peroxide was used in the form of a 30% aqueous solution, and potassium iodide in the form of a 0.5-10.0% solution.

The method is based on the interaction of two substances, as a result of which the effect of maintaining the optimum acidity (18-20 ° T) of the target product is enhanced up to 3 days [8, prototype]. A possible mechanism for maintaining optimal milk acidity is the chemical reaction of hydrogen peroxide with potassium iodide, followed by the release of iodine. As a result of the introduction of a preservative (hydrogen peroxide 0.05%, potassium iodide 0.0025%), the acidity of skim milk changed from the original 17.6 ° T to 19.4 ° T after 1 day, 21.6 ° T after 2 days. No other milk quality indicators are given.

The disadvantages of the method are the limited number of indicators of milk quality, relatively low shelf life.

The technical result is an increase in the shelf life of milk while maintaining optimal acidity, expanding the scope of indicators of milk quality.

This is achieved by the fact that a preservative of 2.0-2.5 mg / dm ^{3 of} copper sulfate is introduced into drinking pasteurized milk in the form of a 0.1% solution of CuSO ₄ and 0.6-0.8 mg / dm ³ of potassium iodide in in the form of a 0.01% solution of KJ, or 9.0-10.0 mg / dm ^{3 of} disodium salt of ethylenediaminetetraacetic acid (trilon B) in the form of a 1% solution of trilon B with gentle stirring and stored at 4 ± 2 ° С determination of a number of quality indicators and shelf life.

In the proposed method, as well as in the prototype, the mechanism of action of the preservative (in particular, according to the first embodiment) is associated with the reaction of components (CuSO ₄ and KJ) with the release of free iodine, which inhibits the development of undesirable microflora. Moreover, the oxidizing agent (CuSO ₄ ) is stable in time, in contrast to hydrogen peroxide (in the prototype), which gradually decomposes.

The use of these preservatives allows you to extend the shelf life of milk in comparison with the control sample up to 4 days with a decrease in acidity by 3 and 2 ° T, respectively (the first and second processing option).

Example

For testing, we took pasteurized drinking milk in consumer packaging three days before the experiment, samples with a volume of 250 cm ³ , in the control - without treatment, 0.1% CuSO ₄ solution and 0.01% solution were added to sample 01 in 250 cm ³ KJ solution at the rate of 0.9 mg / dm ³ Cu ²⁺ and 0.54 mg / dm ³ KJ, in sample 02 - 1% Trilon B solution at the rate of 10 mg / dm ³ , mixed slightly and stored in the refrigerator at temperature 4 ± 2 ° C. Acidity was determined every day and organoleptic indicators at the end of the experiment.

The results of the experiments are presented in the table.

Table The acidity of milk, ° T Group Start of experience After 1 day After 2 days After 3 days After 4 days The control 16 17 eighteen twenty 22 01 16 17 eighteen eighteen 19 02 16 17 eighteen 19 twenty

Organoleptic indicators, the content of fat (3.8%) and protein (2.8%) did not change compared to the initial indicators. The data in the table show that in the experimental samples (01 and 02) the acidity is lower than in the control by 3 and 2 ° T, respectively.

Thus, in the proposed method, the shelf life of drinking milk was increased to ensure optimal acidity, the scope of milk quality indicators was expanded.

Information sources

1. Krus G.N. Technology of milk and dairy products / G.N. Krus and others // Kolos. - M. - 2008. - P.32-33.

2. GOST 13264-88 Cow's milk. Requirements for the purchase.

3. RU 2308209, 10.20.2007.

4. GOST 52090-2003 Drinking milk.

5. RU 2062582, 06/27/1996.

6. RU 2136165, 09/10/1999.

7. RU 2285419, 10.20.2006.

8. SU 1600666, 10.23.1990.

Claims (1)

A method of preserving pasteurized drinking milk, comprising adding a preservative to the pasteurized drinking milk, characterized in that copper sulfate in a dose of 2.0-2.5 mg / dm ³ and 0.6-0.8 mg / dm ³ iodine is used as a preservative potassium, or a 1% solution of Trilon B with gentle stirring and stored at 4 ± 2 ° C.