RU2159806C1 - Strain saccharomyces cerevisae for preparation of biomass of baker's yeast - Google Patents

Abstract

FIELD: applied microbiology. SUBSTANCE: baker's yeast strain incapable of assimilating fructose is constructed and registered in All-Russian collection of industrial microorganisms as Y2477. EFFECT: reduced amount of sugar in sweet bakery product receipts and increased level of fructose in products. 2 tbl, 2 ex

Description

 The invention relates to the microbiological, baking and yeast industries.

 Currently, strains capable of utilization of most monosugars, including fructose, are used to produce baker's yeast. The use of such yeast in baking products whose formulations contain sugar (sucrose) is associated with the breakdown of sucrose to glucose and fructose, which are assimilated by the yeast during testing. Since the main sweetness of the products is associated with the presence of sucrose or fructose, it decreases during the test preparation.

 Thus, the drawback of all baker's yeast available today is their ability to utilize fructose, leading to increased sugar consumption.

 The aim of this invention is to create a strain of baker's yeast that does not absorb fructose. The use of such yeast will allow the production of sweet baked goods with a lower sugar content due to the accumulation of fructose in the dough, which is the preferred food product and has a sweetness ratio of 1.7 compared to sucrose.

The strain Saccharomyces cerevisiae 8280-30A was obtained as a result of mutagenesis of haploid yeast segregants according to the Fru ^- trait and subsequent selection and hybridological analysis of the isolated mutants.

 The strain is deposited in the All-Russian collection of industrial microorganisms (VKPM) under the number Y2477.

 The strain is characterized by the following cultural-morphological and physiological-biochemical characteristics.

 Vegetative cells of a two-day culture grown on solid nutrient medium with 2% glucose as the sole carbon source have an elongated, less often rounded shape, cell size 3.0 x 6.5 μm, protoplasm homogeneous, reproduction by budding.

When grown on solid medium containing yeast extract and peptone (YEP) at 30 ^° C. after 72 hours of growth, the colonies are as follows:
1) on a YEP medium with glucose of a white colony with a smooth edge, a shiny surface, a cone-shaped profile, a creamy consistency;
2) on YEP medium with sucrose colony of white color with a smooth edge, matte surface, lenticular profile and grainy consistency;
3) on YEP medium with galactose colony of white color with a matte surface, a smooth edge, a convex profile and a coarse consistency.

Liquid Growth
In the malt wort at 35 ^o C during the first 24 hours of cultivation, the liquid is cloudy, the precipitate is white, does not clump, does not form a parietal film, and the smell of ethanol.

 On YEP medium containing 3% starch for 20 hours of cultivation, the liquid is cloudy, the characteristic smell of yeast.

Optional aerob. The growth temperature is 23-34-50 ^o C (optimum - 32 ^o C). The pH during cultivation is 3.8-6.0 (optimum is 4.5).

 Assimilation of carbon sources: ferments glucose, galactose, maltose, sucrose, dextrins.

 Assimilation of nitrogen sources: assimilates amino acids, urea, ammonium sulfate, ammonium nitrate.

 Distinctive features: when cultivated on solid YEP medium with fructose, residual growth is observed without the formation of separate colonies.

 The strain Saccharomyces cerevisiae VKPM Y 2477 is non-pathogenic.

The strain is stored on an agarized rich medium with glucose for 4 months at + 4 ^o C.

 Intended use examples.

Example 1. Cells of the yeast strain Y2477 are seeded in flasks with YEP nutrient medium with glucose (2%), which are incubated on a shaker at 30 ^o C for 48 hours. The final density of the yeast culture is OD 34. The yeast biomass is separated by centrifugation and washed once with distilled water.

For the thus obtained biomass of yeast strain Y2477, baking parameters are determined by standard methods (1), which have the following meanings:
zymase activity - 52 min;
maltase activity - 49 min;
lifting force - 56 min.

Example 2. The biomass of the yeast strain Y2477 obtained in example 1, is used for baking bread with the following recipe:
premium flour - 375 g
salt - 6 g
sugar - 21 g
oil - 23 g
water - 270 g
yeast - 24 g
After kneading, the dough passes the proofing stage for 1 h 50 min. Baking lasts 1 hour.

 Indicators of finished products are shown in table 1.

 Sugar content is determined in bread samples. The results obtained are presented in table.2.

 Thus, as can be seen from the presented results, when using yeast strain Y2477 in the bread, an accumulation of an increased amount of fructose occurs.

Sources of information
1. Instructions for microbiological and technological control of yeast production. M .: Light and food industry, 1984, p. 191.

Claims (1)

 Strain Saccharomyces cerevisiae VKPM Y 2477 for obtaining biomass of baker's yeast.

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