Lactobacillus delbrueckii subsp. bulgaricus strain with low beta-galactase activity and application thereof

A technology of the Bulgarian subspecies, Lactobacillus delbrueckii, which is applied in applications, bacteria, dairy products, etc., to achieve the effects of reducing metabolic activity, stabilizing performance, and slowing acidification

Inactive Publication Date: 2015-06-10
NORTHEAST AGRICULTURAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there are many ways to control post-acidification by improving the technological level, but none of them can solve the problem fundamentally, and the genetic stability of mutation breeding and genetic engineering is affected and restricted by many factors. Ongol et al. proposed that there may be some spontaneous Deficient strains of this strain, the production of weak post-acidified yogurt with this strain can be a new way

Method used

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  • Lactobacillus delbrueckii subsp. bulgaricus strain with low beta-galactase activity and application thereof
  • Lactobacillus delbrueckii subsp. bulgaricus strain with low beta-galactase activity and application thereof
  • Lactobacillus delbrueckii subsp. bulgaricus strain with low beta-galactase activity and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Example 1 Screening of Lactobacillus delbrueckii subspecies KLDS1002 with low β-galactase activity

[0039] (1) screening

[0040] Fifteen strains of Lactobacillus bulgaricus isolated from traditional dairy products were activated 2-3 times and then inoculated into 11% skim milk, fermented by a single strain, and post-ripened for 24 hours to measure the β-galactosidase activity of each strain. Determination method: first take 50mL of fermented milk and mix it with 1% EDTA (pH=12, 4°C), so that the mass of each gram of sample is greater than 20mg EDTA, the main purpose is to chelate Ca through EDTA 2+ , dissolve the coagulated milk protein in the sample, then centrifuge at 5520g for 10min (4°C), remove the supernatant, wash the bacterial cells twice with 1mL of 20mmol / L phosphate buffer (pH=7.0), add 10mL of 20mmol / L phosphate buffer solution in the bacterial cells, after centrifugation at 8000r / min for 10min, the bacterial cells were collected, and then 8mL of 20mmol / ...

Embodiment 2

[0047] Example 2 Experiment on the relationship between Lactobacillus delbrueckii subsp. bulgaricus KLDS1002 with low β-galactase activity and post-acidification

[0048] (1) Determination of β-galactosidase activity

[0049] The intracellular enzymes were crudely extracted by lysozyme wall breaking method, and then the enzyme activity of β-galactosidase was determined by ONPG colorimetry. One enzyme activity unit (U) refers to the amount of enzyme required to release 1 μmol ONPG per minute at 37°C.

[0050] (2) Test the enzyme activity of β-galactosidase in the fermented milk of the test strain Lactobacillus delbrueckii subsp. bulgaricus KLDS1002 and the control commercial strain G-495 at 4°C on the 1st, 4th, 10d and 13d respectively, pH value and acidity, the results are shown in Table 2, figure 1 and figure 2 .

[0051] (3) Enzyme activity and acidity comparison measurement results

[0052] From Table 2, figure 1 and figure 2It can be seen that the post-acidificati...

Embodiment 3

[0055] Example 3 Determination of physiological characteristics of Lactobacillus delbrueckii subsp. bulgaricus strain KLDS1002

[0056] (1) Determination of growth performance

[0057] The test strain Lactobacillus delbrueckii subsp. bulgaricus KLDS1002 and the control bacteria G-495 were activated for two generations and then inoculated in MRS liquid medium at 3% and cultured at 37°C at 0, 2, 4, 6, 8, 10, Samples were taken at 12, 14, 16, 18, 20, 22, 24, 36 and 48 hours to determine the concentration of bacteria, and the results are shown in image 3 .

[0058] (2) Determination of acid resistance

[0059] Inoculate the activated Lactobacillus delbrueckii subsp. bulgaricus KLDS1002 and G-495 in MRS liquid medium. After culturing at 37°C for 16 hours, take 3% of the inoculum from each sample and inoculate them at pH 3.0 and 4.5 respectively. , 5.5, 6.5 MRS liquid medium, cultured at 37°C for 12h. The number of viable bacteria was calculated by the plate colony counting met...

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Abstract

The invention relates to lactobacillus bulgaricus with low beta-galactase activity and application thereof. The lactobacillus bulgaricus is classified and named as lactobacillus delbrueckii subsp. bulgaricus, and the microbial preservation number is CGMCC No.9957. The strain is screened from the lactobacillus bulgaricus separated from a traditional milk product and has relatively stable performance, the instability, caused by overmuch passage number, similar to mutant strains is avoided, and furthermore, weak post-acidification capacity can be preserved all the time, so that the post-acidification of yoghourt in a preservation period can be effectively delayed in the actual application, and the shelf life of the yoghourt can be prolonged; furthermore, the strain has an excellent fermentation property and can be used as a weak post-acidification yoghourt fermentation agent to be applied to industrialization.

Description

technical field [0001] The invention relates to a screened Lactobacillus bulgaricus strain with low β-galactase activity and the application of the strain in fermentation industry, which belongs to the technical field of biological fermentation. Background technique [0002] The probiotics in fermented dairy products can not only improve the quality of food, but also provide the human body with beneficial effects such as improving intestinal function and promoting substance absorption. Yogurt is the most common dairy product fermented by lactic acid bacteria. It mainly uses Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus as starter, fermented at 42°C to pH 4.5, stored at low temperature, transported and sold . In the process after fermentation and before eating, lactic acid bacteria can still continue to multiply and ferment lactose to produce lactic acid, which further reduces the pH value and produces an unacceptable over-sour taste. Less, redu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12N1/20A23C9/123C12R1/225
CPCA23C9/1238C12N1/205C12R2001/225
Inventor 霍贵成曹凤波孙懿琳李春燕李媛媛周晶王晓明刘宾
Owner NORTHEAST AGRICULTURAL UNIVERSITY
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