RU1839185C - Strain of bacterium lactobacillus acidophilus used in bacterial starter culture composition for lactic acid products - Google Patents

Description

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

Strains of the species Lactobaclllus acidophilus are known that are used in starter cultures for fermented milk products 1. The strains have a number of production-valuable properties: they have good milk-clotting activity, inhibit the growth of intestinal microflora, and are resistant to antibiotics. However, all these strains are characterized by high energy acid formation, which leads to a deterioration in the organoleptic characteristics of fermented milk products.

The closest in technical essence and the achieved positive effect is the lactic acid bacteria strain Lactobaclllus acidophilus 5DS (CMPM 8-2846) used in the production of dairy products (2). The strain actively develops in milk at low cultivation temperatures with a low acid storage limit, has a stable ability to synthesize extracellular carbohydrate complexes, is able to activate the growth of mucous varieties of lactic streptococci and stabilize them according to their main properties. The disadvantages of the strain are high marginal acidity at a temperature of 40-45 ° C, low proteolytic activity and inability to activate the development of thermophilic lactic acid bacteria.

The purpose of the invention is to obtain a new strain of lactic acid bacteria of the species Lactobacilius acidophilus AP-4, characterized by high proteolytic activity, low acid accumulation over the entire temperature range of cell development and the ability to stimulate the development of thermophilic lactic acid bacteria.

The strain Lactobacillus acidophilus AP-4 is a mutant and was obtained by treating the cells of the Lactobacllius acidophilus strain CMMP B-2846 with acriflavine at a mutagen concentration of 4 mg / ml and exposure time of 12 hours.

The identification of the strain was carried out according to the Bergi identifier.

Strain Lb. acldophllus AR-4 is stored in the All-Union Collection of Industrial Microorganisms of the Institute VNIIgenetika under the collector number VKPM B-5254 and is characterized by the following features.

Morphological signs. Cells are rod-shaped, gram-positive, motionless, catalase-negative, do not form spores and capsules. P zmera

17-hour culture cells in milk are (1.0-1.2 x (8-15) microns.

Cultural signs. On the surface of milk agar, a 48-hour culture forms smooth white colonies e equal

edges with a diameter of 1.5-3.0 mm.

On agar with hydrolyzed milk, colonies of a 48-hour culture, surface colonies are smooth with even edges 2-3 mm in diameter, and deep ones are arachnid.

5 After 48 h of cultivation, on m-sopeptic agar, the strain forms smooth white colonies with even edges 3-4 mm in diameter on the surface of the medium and in the form of spiders in deep layers.

0, when the strain develops in milk, casein hydrolysis is observed, not accompanied by coagulation.

In m sopeptone broth, peptone-salt medium, hydrolyzed milk, the development of the strain causes a dense uniform turbidity of the medium.

The optimum cell development temperature is 30-37 ° C, maximum 50 ° C, minimum 10 ° C. Optimum acidity

0 medium 6.2-6.5 units pH

Physiological and biochemical characteristics. The strain assimilates glucose and mannose. The remaining carbohydrates are not disposed of.

Milk does not clot, litmus milk and milk with methylene blue does not restore. The maximum acidity of the strain in milk at a temperature of (30-37) ° C-26 ° T.

The strain liquefies gelatin, hydrolyzes casein, forms ammonia from arginine, and increases the content of amino nitrogen in milk by 60-63 mg%.

The strain develops in the presence of 0.5% phenol and 0.5 and. e. / ml penicillin.

5 The strain is phage resistant. A comparative assessment of the obtained mutant Lactobacillus acidophilus AP-4 and the original strain of Lactobacillus acidophilus 5DS is given in table. 1. The properties of the strains were determined in

0 identical conditions x. Cell morphology, acidity, proteolytic activity, cell number, cell growth of mesophilic and thermophilic lactic acid bacteria were determined after a 24-hour

5 cultivations in milk. Carbohydrate utilization was tested in peptone salt medium after 48 hours of cultivation at the optimum temperature.

The data given in the R table indicate that. what is the long strain

Lactobacillusacidophilus AP-4 differs from the known high proteolytic activity, the absence of acid accumulation from lactose, and a high stimulating effect on the development of mesophilic and thermophilic lactic acid bacteria.

The strain Lactobacillus acidophilus AP-4 is proposed for use in ecterial starter cultures for fermented milk products,

Example 1. The preparation of varenets using starter culture, which includes the proposed strain of Lb. acidophilus AP-4.

The following starter cultures are used: Streptococcus thermophilus 15, ..actobacillus buldaricus BP-28 and .actobacilius acidophilus AP-4.

The preparation of the starter culture is carried out in two stages.

In order to obtain a laboratory starter culture, 1 portion of the starter culture of the above composition is consumed with 2 l of sterile skim milk. Fermented milk is stirred and kept at a temperature of 0 ° C for 4 hours.

To prepare industrial aquasque, 100 g of sterile skim milk are added in 2 l of laboratory ferment. The mixture was thoroughly mixed and left at a temperature of 40 ° C for 3 hours until the clot formed.

The characteristics of the starter culture are given in table.2.

To obtain jam, butts of milk with an N fatty acid fraction of 3.5% are sterilized at a temperature of 118 ° C for 5 minutes, then cooled to a temperature of 40 ° C. 100 kg of commercial sourdough are added to the caught milk. The mixture was incubated at 40 ° C for 3 hours until a clot formed. The finished product is mixed; mixed and served on bottling. .

Product characteristics are given in table. 3

Example 2. The preparation of varenets using sourdough, which includes

A known strain of Lb. acidophilus.5

ds.

M

The product is prepared according to example 1 with the exchange of strain Lb. acidophilus AP-4 strain A L acidophlJus 5 DS. .

The product has an excessively sour taste and insufficiently dense texture.

Example 3. Preparation of acidophilic milk using a starter culture, which includes the proposed W amm Lb. acidophilus AP-4.

The starter culture consists of the following strains: Lb. acidophlius 38 and Lb. / -. Mophilus AP-4.

5

10

fifteen

twenty

5

0

5

5

0

0

5

Laboratory and industrial starter culture was prepared analogously to example 1.

To prepare acidophilus milk, 2 tons of milk with a fat mass fraction of 3.2% are pasteurized at a temperature of 87 ° C for 10 minutes and cooled to a temperature of 40 ° C. 60 kg of production sourdough is added to the prepared milk, the mixture is stirred and left at a temperature of 40 ° C for 3 hours until a sinter is formed. The product is stirred while cooling and fed to a bottling.

Product specifications are given in the table. Z.

Example 4. Preparation of acidophilic milk with the use of yeast, which includes strain Lb. acidophilus 5 DS.

The product is ready. : t according to example 3 with the replacement of the proposed strain of Lactobacliius acidophilus AP-4 with a known strain of Lb. acidophilus 5 DS.

The resulting product has a high acidity. The fermentation process lasts bh

Example 5. Preparation of a fermented milk product Sour cream with a mass fraction of fat of 10% using the proposed strain Lb. acidophifus tiP-4.

Use a starter culture containing the following strains: Leuconostoc iactts RD-5, Leuconostoe dextranicum RD-2. Larvococciis lactis subsp; cremcris H-1. L-ctcbacfrus casei 18, Acetobacter acet RD-10 h Lactobecilius acidophilus AP-4.

In order to prepare laboratory eekvaski in 1 liter of sterile skim milk, 1 portion of the Sourdough of the above composition is added. Fermented milk-3 after stirring is kept at a temperature of 30 ° C for 7.5 hours.

To obtain industrial starter culture in 70 kg of sterile skim milk, 2 L of laboratory starter culture was added, the mixture was stirred and kept at a temperature of 30 ° C for 3.5 hours.

To prepare a fermented milk product, 3 tons of fat-normalized cream are pasteurized at a temperature of 95 ° C for 5 minutes and cooled to a temperature of 30 ° C. To the prepared cream, 70 kg of industrial sourdough is added. The mixture was stirred and held at 30 ° C for 3.5 hours until a clot formed. Fermented product is mixed and served on roses / seam.

Product characteristics are given in B table. 3.

Example 6. Preparation of fermented milk product Smegznka with a mass fraction of fat of 10% using a starter culture, which includes the known strain of Lb, acldophilus 5 DS.

The product is prepared according to example 5 with the replacement of the proposed strain of Lb, acldophllus AP-4 with a known strain of Lb. acldophllus 5 DS.

The product has excessive acidity; the fermentation process lasts 7 hours.

In the table. 2 shows a comparative characteristic of bacterial starter cultures for fermented milk products prepared using the proposed and known strains. The data given indicate. that the use of the proposed strain improves milk coagulation and proteolytic

0

leaven activity, content of viable bacterial cells in it.

In the table. 3 shows a comparative characteristic of fermented milk products prepared using the proposed and known strains. The presented data show that the use of starter cultures, including the proposed strain, allows to obtain products with improved taste, texture and high content of low molecular weight nitrogenous components.

(56) Copyright certificate of the USSR 15 No. 1004471, cl. C 12 N 1/20, 1981.

USSR copyright certificate. No. 1266858, cl. C 12 N 1/20. 1984.

Table

Continuation of the table. 2

Table3

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Claims (1)

The claims The bacterial strain Lactobaclllus is composed of bacterial starter cultures for acid-cidophllus VKPM B-5254 used in Dairy Products.