SU1546482A1 - Strain of sour milk bacteria streptococcus cremoris used in ferments for making sour milk products - Google Patents

Abstract

This invention relates to biotechnology. The purpose of the invention is to obtain a new strain of lactic acid bacteria STREPTOCOCCUS CREMORIS VKPM B-3963, which has the ability to multiply at a temperature of 40-43 ° C and synthesize aromatic substances. Strain / sh / STREPTOCOCCUS CREMORIS VKPM B-3963 / BH-5 / was obtained by exposure to UV radiation on the strain S. CREMORIS H-1, followed by growing the irradiated cells at 43 ° C for 12 hours. 43 ° C and enrich the taste of fermented milk through the synthesis of aromatic substances. Strain S. CREMORIS BH-5 coagulates milk at a temperature of 25–30 ° C in 5.0–5.5 h. Synthesizes in milk 1.9–2.0% of extracellular mucous substances that increase the viscosity of the clot to 2.5 Pa ^. with. Extreme acidity in milk after 7 days at the optimum growth temperature - 115 ° T. Strain phage-resistant due to the presence of a mucous capsule. 3 tab.

Description

The invention relates to biotechnology, is a new strain of lactic acid bacteria, and may find application in the production of fermented milk products.

The purpose of the invention is to obtain a new strain of lactic acid bacteria Streptococcus cremoris VKPM B-3963 (BH-5), which has the ability to multiply at 0-43 ° C and synthesize aromatic substances.

The proposed S. cremoris BH-5 strain is a mutant of the S. cremoris H-1 strain and obtained by Y-irradiation of the initial strain with an energy exposure of 12.86 J / m2 with subsequent cultivation of irradiated cells at k $ C

for 12 hours. UV irradiation was carried out with a BUV-15 lamp, surface flux density of 0.22 W / m2.

Strain S. cremoris BH-5 is able to actively develop, synthesize up to 2% of extracellular mucous substances, which allows to improve the consistency of fermented milk products. Strain possesses aroma-forming ability. The cell yield after 12 hours of growth in skimmed milk at 25 ° C is 7-8 billion / ml, and at 0 ° C it is 5-6 billion / ml.

Identification of the strain was performed according to the determinant Bergi.

Morphological signs. Cells are fixed, gram-positive, races; l

35ъ 35

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are supposed to be chains of various lengths, the size of cells in diameter is 0,, S microns, the cells are surrounded by mucous capsules,

Cultural features. On agar with hydrolyzed milk, colonies of 48-hour cultures are round, white, mucous, with a diameter of 0.8-1.0 mm.

On agar with hydrolyzed milk, sucrose, and calcium citrate, the colonies are smooth, round, with even edges, 0, 1 mm in diameter, with bleed zones 1, 2 -1, mm,

On m-peptone agar, 8-hour colonies are smooth, round, 0, 8 mm in diameter.

In hydrolyzed milk and MRS medium, the strain after 12 hours of development forms a dense uniform turbidity.

Physiological and biochemical properties. The optimum growth temperature of the culture is (25-30) ° C, maximum 5 ° С, minimum 8 ° С.

Litmus milk and milk with 0.3% methylene blue restores and coagulates.

Attitude to carbohydrates. Actively ferments lactose, glucose, galactose, mannose, sucrose, maltose. Does not absorb arabinose, xylose, sorbitol, mannitol, dulcite, glycerin, starch. Gelatin does not dilute. From arginine ammonia does not form. Strain phage-resistant. Milk coagulates at the optimum growth temperature and the introduction of 3% of the culture for 5.0-5.5 hours

The maximum acidity in milk is 115 ° T.

A comparative assessment of the initial strain S. cremoris H-1 and the resulting BH-5 mutant was carried out under identical conditions in sterile skimmed milk at a growing temperature of 25 ° C.

Acidity, mucous substances, viscosity, organoleptic evaluation, proteolytic activity, aroma formation were determined immediately after the formation of a clot.

Comparative characteristics of the original strain S, crerioris H-1 and the obtained mutant S. cremoris BH-5 are given in Table. one.

Comparison of the data allows us to conclude that 1 strain of Streptococcus cremoris BH-5 is proposed.

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Compared with the known, it is characterized by the ability to actively propagate in a wider range of temperature limits and the ability to synthesize aromatic substances that improve the taste of the target product. The resulting strain has a higher proteolytic and mucus-forming activity, and forms more viscous clots during the fermentation of milk.

The proposed strain Streptococcus cremoris BH-5 can be used in the composition of baczakvaski for fermented milk products, produced by the reservoir method.

In tab. Figure 2 presents a comparative description of bacterial starters for women and yogurt prepared using Streptococcus cremoris BH-5 and Streptococcus cremoris H-1 strains.

A comparative characteristic of bacterial starters suggests that the use of the proposed strain in their composition allows improving the organoleptic properties of the starters, increasing their milk-clotting, proteolytic activity, the starters acquire the ability to accumulate mucous substances that increase the viscosity of the milk clot and to the biosynthesis of aromatic substances. - enriching the taste of fermented milk.

Comparative characteristics of fermented milk products prepared using starter cultures, including strains of Streptococcus cremoris BH-5 and Streptococcus cremoris H-1, are given in Table. 3

Example 1. Production of a female by the reservoir method using a starter, which includes the proposed Streptococcus cremoris HH-5 strain.

A starter of the following composition is prepared: Streptococcus thermophilus and Streptococcus cremoris BH-5.

For the preparation of a laboratory ferment in 300 ml of sterile skimmed milk, 3% of the combination of the above composition is added.

After fermentation, the milk is thoroughly mixed and kept at kQ ° C for 5 hours until a clot forms. For the preparation of a production ferment in 300 ml of sterile skimmed milk 300 ml of laboratory ferment are added. The mixture is stirred and maintained at 40 ° C for 30 hours until a clot forms.

Characteristics of the leaven are given in table. 2

To obtain a solution, 3 tons of milk, normalized to fat, are heated

go of milk makes an L portion of leaven. The fermented milk is kept in a thermostat at 40 ° C until a clot forms.

For the preparation of the production ferment, 3% laboratory ferment is added to sterile skimmed milk. Fermented milk after re-washing is 95 ° C and maintained at this temperature of incubation is maintained at 40 ° C for 2 hours, then cooled for 3.5 hours until a clot forms, to 40 ° C and 30 kg of production is introduced. leaven is given

no leaven. The process of souring in the table. 2

carried out at 40 ° D until the formation of D for the production of yogurt 2 tons

clot. The resulting product is mixed; 15 normalized milk is pasteurized while being cooled simultaneously at 92 ° C for 2 minutes and cooled.

up to kO ° C and 60 kg of production ferment are introduced. The fermented milk is stirred and kept at the indicated temperature until a clot forms for 3.5 hours. The resulting mixture is dispensed.

Characteristics of the product are given in table. 3

EXAMPLE 2 Preparation of the solution by the reservoir method with the use of milk introduces an L portion of the starter. The fermented milk is kept in a thermostat at 40 ° C until a clot forms.

For the preparation of the production ferment, 3% laboratory ferment is added to sterile skimmed milk. Fermented milk after the change

ferment, which includes the well-known strain Streptococcus cremoris H-1.

The method is carried out according to Example 1, replacing the proposed Streptococcus cremoris BH-5 strain with the known Streptococcus cremoris H-1.

After stirring, the finished product becomes not sufficiently homogeneous - 30 ris H-1. The consistency during storage is carried out according to the application of serum.

Example Preparation of pastoral by the reservoir method using the starter, which includes the proposed Streptococcus cremoris BH-5 strain.

Prepared starter following composition: S. thermophilus, L. bulgaricus, S. cremoris BH-5.

For the preparation of laboratory measurement 3 with the replacement of the proposed strain known.

The resulting product has a lumpy, non-uniform consistency; serum is separated during storage.

kvask. in 2 l of sterile skim the formula of the invention

The strain of lactic acid bacteria Stre tococcus cremoris VKPM B-3963 used in ferments for fermented milk products.

Milk-clotting activity, h5.0-5.5 Titrable acid, T Amount of synthesized mucous substances,% 1.9-2.0 Clot viscosity, Pa.s c, 5, Proteolytic activity (mg% amine nitrogen under milk control 8 , 0 mg) 11.7-12,

The product is stirred while cooling and served for bottling.

Characteristics of the product are presented in Table. 3

PRI me R 4. Preparation of yogurt tank method using sourdough, which includes the well-known strain S. cremomer 3 with the replacement of the proposed strain known.

The resulting product has a lumpy, non-uniform consistency; during storage, the whey separates.

Claims (1)

Formula isob Strain of lactic acid tococcus cremoris VKPM used in ferments of dairy products. T a b l and c a 5.0-5.5 85-90 1.6-1.7 1.8-2.0 10.8-11.0 The number of cells after 12 h of growth in skimmed milk, cells / ml, Taste and smell Pure, sour-Pure, sour-Pure, sour- Pure, milk-sour milk, with a pronounced aroma-aroma Milk-clotting activity, h Titrated acidity, ° T Nitrogen content of free amino groups, mg% Aromat-forming ability, min Viscosity of the clot, Pa-s Synthesis of extracellular mucous membranes,% Table 2 5.0 0 9.9 3.5 85 12.8 7 2.0-2.2 2.8-3.0 2.1-2.6 5.5 85 10.7 2.0-2.2 Taste is clean, Taste is clean. Taste is clean, sour-milk, sour-milk, with t-milk, with a pleasant aroma, consistency, consistency is non-homogeneous, sufficiently non-homogeneous Titrated acidity, ° С Content of aromatic substances (dyeing time in alkaline medium), min Clot viscosity, PG, s The nitrogen content of free amino groups, mg%  Table 3 The taste is clear sour milk, consistency lumpy prone to syneresis 98 8 2.46 12.0 95 0.98 7.3