WO2023065459A1

WO2023065459A1 - Auxiliary fermentation agent and application thereof

Info

Publication number: WO2023065459A1
Application number: PCT/CN2021/133348
Authority: WO
Inventors: 袁庆彬; 冯丽莉; 刘凤昝; 康志远; 魏立华; 王世杰; 张栋; 薛玉玲; 荀一萍
Original assignee: 君乐宝乳业集团有限公司
Priority date: 2021-10-20
Filing date: 2021-11-26
Publication date: 2023-04-27
Also published as: CN115474630A; CN115474630B

Abstract

An auxiliary fermentation agent and an application thereof. The auxiliary fermentation agent comprises Streptococcus thermophilus JMCC0031 and Streptococcus thermophilus JMCC0032 which have a ratio of viable count of 1:0.5-2, and is used as a fermentation agent after compounding with a conventional yogurt fermentation agent to ferment milk or reconstituted milk to prepare yogurt. The aroma and texture of the prepared yogurt are remarkably improved, and the auxiliary fermentation agent does not affect the effect of the conventional yogurt fermentation agent compounded with the auxiliary fermentation agent.

Description

A kind of auxiliary fermentation agent and its application

technical field

The invention belongs to the technical field of dairy products, and relates to an auxiliary starter, in particular to an auxiliary starter and application thereof.

Background technique

With the development of my country's economy and the improvement of people's living standards, consumers' demand for lactic acid bacteria is increasing day by day, especially for fermented milk. The choice of starter is very important in the process of fermented milk preparation, and the development of starter with independent intellectual property rights will help improve the core competitiveness of my country's fermented milk product manufacturers.

In the process of yogurt production, due to changes in the fermentation substrate, such as changes in various nutritional indicators of milk with seasonal changes, the quality of yogurt is unstable, mostly manifested as poor texture and insufficient aroma. When the texture of yogurt is not good, it is reflected in rough taste, strong powdery feeling, water separation of coagulated products or too thin of stirred products. Therefore, it is necessary to develop an auxiliary starter that can improve the aroma and texture of yogurt fermentation to improve Taste and aroma of fermented milk.

The Chinese invention patent application with the application number 201910644913.X discloses a preparation method of a weak post-sour yogurt composite starter, its application, and corresponding yogurt. , Streptococcus thermophilus JMCC0019, Streptococcus thermophilus JMCC0022 and Lactobacillus delbrueckii subsp. bulgaricus JMCC0018 are mixed with the number of bacteria 1000: (1～10000): (1～1000): (1～100), The acid effect is obvious after the starter is weak, but there is still room for improvement in the texture of the prepared yogurt.

Contents of the invention

The object of the present invention is to provide an auxiliary starter and its application. The auxiliary starter is combined with a specific type of fermentation strain, and is used for compounding with conventional yogurt starter to ferment and prepare yogurt with good aroma and texture. dairy products.

In order to achieve the above object, the technical scheme adopted in the present invention is:

An auxiliary fermentation agent, which includes Streptococcus thermophilus JMCC0031 and Streptococcus thermophilus JMCC0032 with a ratio of viable bacteria number of 1:0.5-2.

As a definition, it includes Streptococcus thermophilus JMCC0031 and Streptococcus thermophilus JMCC0032 with a viable count ratio of 1:1.

The present invention also provides an application of the above-mentioned auxiliary starter, which is used to prepare yogurt by fermenting milk or reconstituted milk after compounding with conventional yogurt starter.

As a limitation, the compounding is the combination of auxiliary starter and conventional yogurt starter in a mass ratio of 1:1-3.

As another limitation, the conventional yogurt starter is yogurt compound starter JLB-1510.

The yogurt compound starter JLB-1510 consists of four bacterial powders of Streptococcus thermophilus JMCC16, Streptococcus thermophilus JMCC0019, Streptococcus thermophilus JMCC0022 and Lactobacillus delbrueckii subsp. (1~1000): (1~100) mixed.

In the present invention:

Streptococcus thermophilus JMCC0031 is isolated from traditional fermented milk in Xinjiang. The strain has been preserved in the General Microorganism Culture Collection Center of China Microbiology Culture Collection Management Committee on May 18, 2021. The preservation number is CGMCC NO.22558, Latin The name is Streptococcus thermophiles; its 16SrRNA gene sequence is as follows:

Streptococcus thermophilus JMCC0032 was screened from fermented dairy products in Xinjiang. The strain was deposited in the General Microorganism Culture Collection Center of China Microbiology Culture Collection Management Committee on May 18, 2021, with the preservation number CGMCC NO.22559 , the Latin name is Streptococcus thermophiles. Its 16SrRNA gene sequence is as follows:

The present invention has adopted above-mentioned technical scheme, and it compares with prior art, and the technical progress that obtains is:

The auxiliary fermentation agent of the present invention is prepared from Streptococcus thermophilus JMCC0031 and Streptococcus thermophilus JMCC0032 according to a specific ratio, wherein Streptococcus thermophilus JMCC0031 has the characteristic of increasing the viscosity of fermented milk, and Streptococcus thermophilus JMCC0032 has the ability to produce aroma substances good. The auxiliary starter and conventional yogurt starter are compounded in proportion for yogurt fermentation, which can improve the texture and aroma of yogurt with a small amount of addition, while not affecting the fermentation characteristics of the conventional yogurt starter itself; the auxiliary starter and conventional yogurt The yogurt starter works together to solve the problems of poor texture and insufficient aroma of yogurt, significantly improve the taste, and avoid water separation of solidified products and too thin of stirred products;

The application method of the auxiliary fermentation agent of the present invention has high operability and is suitable for industrial production.

The present invention will be described in further detail below in conjunction with specific embodiments.

Description of drawings

Fig. 1 is that Streptococcus thermophilus JMCC0031 in embodiment 1 has no influence experimental result figure to other bacterial strains fermentation;

FIG. 2 is a graph showing the experimental results of Streptococcus thermophilus JMCC0032 having no effect on the fermentation of other bacterial strains in Example 1.

Detailed ways

The present invention will be described in further detail below through specific examples. It should be understood that the described embodiments are only used to explain the present invention, not to limit the present invention.

If the specific conditions of the experiment are not specified in the following examples, usually follow the conventional conditions, or according to the conditions recommended by the reagent company; the reagents and consumables used in the following examples, unless otherwise specified, can be obtained through commercial channels Obtained and analyzed using analytically pure reagents that meet national standards, the experimental water is pure water, and the methods used are conventional processes in this field unless otherwise specified.

Embodiment 1 A kind of auxiliary fermentation agent and its application

This embodiment is an auxiliary starter and its application. The auxiliary starter is 100 g of Streptococcus thermophilus JMCC0031 freeze-dried bacterial powder and 100 g of Streptococcus thermophilus JMCC0032 freeze-dried bacterial powder with a viable count of 1×10 ¹⁰ CFU/g. It is prepared by mixing dry bacteria powder, and the marking code of this auxiliary starter is F1. After compounding 200g of auxiliary starter F1 and 600g of yogurt compound starter JLB-1510 to obtain a compound starter, prepare yogurt by fermenting milk. The yogurt preparation method refers to the yogurt compound starter JLB-1510 provided by Hebei Yiran Biotechnology Co., Ltd. The only difference is that the yogurt compound starter JLB-1510 is replaced by the compound starter.

Among them, Streptococcus thermophilus JMCC0031 has no effect on the fermentation of other strains and can significantly improve the viscosity, texture and taste of fermented milk. The proof experiment is as follows:

(I1) Streptococcus thermophilus JMCC0031 has no effect on the fermentation of other strains

The activated Streptococcus thermophilus JMCC0031 strain was inoculated into sterilized raw milk at an inoculation amount of 1×10 ⁶ CFU/mL, and the pH value of Streptococcus thermophilus JMCC0031 in the sterilized milk was recorded by online pH monitoring. Another strain of Streptococcus thermophilus JMCC0033 was used as a reference to investigate the influence of Streptococcus thermophilus JMCC0031 on the fermentation speed characteristics of other fermentation strains and equal combinations with other strains.

Among them, Streptococcus thermophilus JMCC0033 has been preserved in the Culture Collection Center of the Institute of Microbiology, Chinese Academy of Sciences. The preservation address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The preservation date is May 18, 2021, and the preservation number is CGMCC NO.22560. The Latin name is Streptococcus thermophiles, and its 16SrRNA gene sequence is as follows:

The results are shown in Figure 1. The fermentation speed of Streptococcus thermophilus JMCC0031 was slow, and the pH reached 4.5 and tended to be stable after 20 hours. JMCC0031 had no significant effect on the fermentation rate of Streptococcus thermophilus JMCC0033, and had no significant effect on the final pH. Therefore, the Streptococcus thermophilus JMCC0031 used in the present invention has the characteristics of slow fermentation speed, and the post-acid weak machine does not affect the fermentation of other bacterial strains.

According to the above method, it was detected that Streptococcus thermophilus JMCC0031 had no effect on the fermentation of Streptococcus thermophilus JMCC0032 and the strains in the yogurt compound starter JLB-1510.

(I2) Streptococcus thermophilus JMCC0031 increases the viscosity of fermented milk

Activate the following 7 kinds of strains or combinations: Streptococcus thermophilus JMCC0031, Streptococcus thermophilus JMCC0032, Streptococcus thermophilus JMCC0033, yogurt compound starter JLB-1510, yogurt compound starter JLB-1510 and Streptococcus thermophilus JMCC0031 by Combination agent with a mass ratio of 1:1, yogurt compound starter JLB-1510 and Streptococcus thermophilus JMCC0031 at a mass ratio of 2:1, and yogurt compound starter JLB-1510 and Streptococcus thermophilus JMCC0031 The combination agent compounded with a mass ratio of 3:1 is activated sequentially and set aside.

Inoculate the activated strains or combinations according to the inoculation amount of 30g in 1kg of raw milk and 70g of white sugar, ferment at 42°C until the pH is 4.5, and place them at 4°C for 24h after demulsification by the agitator to obtain fermented Milk was placed at room temperature for 4 hours to measure its viscosity with a viscometer, and the average value was obtained by repeating three times. The results are shown in Table 1.

Table 1 Viscosity test results after fermentation

It can be seen from the experimental results that compared with other strains, Streptococcus thermophilus JMCC0031 increases the viscosity of fermented milk, and at the same time, when it is assisted with yogurt compound starter JLB-1510, it significantly improves the yield of yogurt compound starter JLB-1510. The viscosity of fermented milk, and the addition amount increased from 1:3 to 1:1, had no obvious effect on the increase of viscosity.

(I3) Streptococcus thermophilus JMCC0031 improves the texture and taste of fermented milk

Convene 10 expert-level sensory evaluation personnel to conduct comprehensive evaluation on the fermented milk prepared by the above-mentioned 7 strains or combinations. The sensory evaluation method is to use a 10-point intensity scale method for sensory characteristics (10 to 0 means extremely strong to imperceptible). This method is used to evaluate the mouth viscosity, powdery feeling, smoothness, and cohesiveness of the above-mentioned fermented milk samples. The sensory test results are shown in Table 2:

Table 2 Sensory test results

It can be seen from the experimental results that in addition to exhibiting good texture characteristics of fermented yogurt, Streptococcus thermophilus JMCC0031, as an auxiliary strain of starter, improves the texture and taste of yogurt.

In summary, the fermented milk with Streptococcus thermophilus JMCC0031 as a starter strain has a good texture. At the same time, when it is used as an auxiliary starter strain for fermentation, the fermentation curve of the original starter and the post-acidity will not change the texture of the fermented milk at the same time. Visible texture improvement effect.

In addition, Streptococcus thermophilus JMCC0032 has no effect on the fermentation of other strains and can significantly improve the aroma of fermented milk. The proof experiment is as follows:

(II1) Streptococcus thermophilus JMCC0032 has no effect on the fermentation of other strains

The activated Streptococcus thermophilus JMCC0032 strain was inoculated into sterilized raw milk at an inoculation amount of 1×10 ⁶ CFU/mL, and the pH value of Streptococcus thermophilus JMCC0031 in the sterilized milk was recorded by online pH monitoring. Another strain of Streptococcus thermophilus JMCC0033 was used as a reference to investigate the influence of Streptococcus thermophilus JMCC0032 on the fermentation speed characteristics of other fermentation strains and equal combinations with other strains.

The results are shown in Figure 2. The pH of Streptococcus thermophilus JMCC0032 reached 4.5 after 9 hours of fermentation alone, and the final pH reached about 4.2 at the end of the fermentation and tended to be stable. At the same time, it can be observed through the combined fermentation curve of Streptococcus thermophilus JMCC0033 and these two bacteria Streptococcus thermophilus JMCC0032 had no significant effect on the fermentation rate of Streptococcus thermophilus JMCC0033, and at the same time had no significant effect on the final pH, and did not affect post-acid.

(II2) Streptococcus thermophilus JMCC0032 improves the aroma of fermented milk

Activation of the following 7 bacterial strains or combinations: Streptococcus thermophilus JMCC0031, Streptococcus thermophilus JMCC0032, Streptococcus thermophilus JMCC0033, yogurt compound starter JLB-1510, Streptococcus thermophilus JMCC0031 and Streptococcus thermophilus JMCC0032 by mass ratio 3:1 compound composition, the compound composition of Streptococcus thermophilus JMCC0033 and Streptococcus thermophilus JMCC0032 in a mass ratio of 3:1, and the yogurt compound starter JLB-1510 and Streptococcus thermophilus JMCC0032 in a mass ratio of 3: 1 The compounded combination agent is activated sequentially and set aside.

The activated strains or combinations were inoculated according to the inoculation amount of 30g in 1kg of raw milk and 70g of white sugar, fermented at 42°C for 5.5h, and then placed at 4°C for 24h after being demulsified by a stirrer to prepare fermented milk respectively. Adopt gas chromatography to measure fragrance substance acetaldehyde and diacetyl (i.e. 2,3-butanedione), the standard sample mass concentration of acetaldehyde and diacetyl is 25mg/L, according to the formula Ci=(Ai÷A0)× C0 calculates the mass concentration of aroma components in each fermented milk, and the results are shown in Table 3.

In the formula:

Ci is the mass concentration of aroma components in the sample;

Ai is the sample chromatographic peak area;

A0 represents the standard sample chromatographic peak area;

C0 represents the external standard concentration of the standard sample.

Convene 10 expert-level sensory evaluation personnel to conduct a comprehensive evaluation of the fermented milk produced by the above-mentioned 7 strains or combinations. The sensory evaluation method is a 10-point intensity scale method for sensory properties (10 to 0 means extremely strong to imperceptible) , using this method to carry out the aroma sensory test on the above-mentioned fermented milk samples, the results are shown in Table 3:

Table 3 Mass concentration of aroma components and aroma sensory test results

From the results in Table 3, it was found that after compounding with Streptococcus thermophilus JMCC0032, the ratios of acetaldehyde to diacetyl of Streptococcus thermophilus JMCC0031, Streptococcus thermophilus JMCC0032, and yogurt compound starter JLB-1510 were closer to those when they were fermented alone At 0.3-0.4, this result indicates that the flavor of fermented milk is better; at the same time, the score in the aroma sensory test also increased.

In summary, Streptococcus thermophilus JMCC0032 can improve the aroma index of fermented milk without affecting the post-fermented milk acid.

Embodiment 2-6 Auxiliary fermentation agent and application thereof

Examples 2-6 are respectively a kind of auxiliary starter and its application. These auxiliary starters are Streptococcus thermophilus with a viable count of 1×10 ¹⁰ CFU/g and a mass ratio of 1:0.5-2. JMCC0031 and Streptococcus thermophilus JMCC0032 freeze-dried bacterial powder are mixed and prepared, and the marking code of these auxiliary fermentation agents is F2-6. After the auxiliary starter F2-F6 is compounded with 1-3 times the mass of yogurt compound starter JLB-1510 to obtain a compound starter, yogurt is prepared by fermenting reconstituted milk. The yogurt preparation method is provided by Hebei Yiran Biotechnology Co., Ltd. The method of using the yogurt compound starter JLB-1510, the only difference is that the yogurt compound starter JLB-1510 is replaced by a compound starter, and the specific ratio data is shown in Table 4.

Control group: the yogurt fermented only with yogurt compound starter JLB-1510 was used as the control group.

The fermentation time, aroma sensory test, powdery feeling and smoothness of the yogurt prepared in Examples 2-6 and the yogurt of the control group were tested respectively, and the results are shown in Table 4.

Table 4 Compound starter ratio and test results

As can be seen from Table 4, compared with Examples 2-4, when the addition amount of Streptococcus thermophilus JMCC0031 is increased from 5g to 7.5g, the improvement effect on the texture characteristics of powdery feeling and smoothness is more obvious, and when it is increased to 10g, there is no Significantly improved; when the addition of Streptococcus thermophilus JMCC0032 reached 7.5g, the aroma improvement effect was better, and the fermentation time was not greatly affected. It shows that after compounding Streptococcus thermophilus JMCC0031 and Streptococcus thermophilus JMCC0032 at a mass ratio of 1:1, and then adding it to fermented milk with a yogurt compound starter JLB-1510 at a mass ratio of 1:3, the aroma, powdery and smooth The comprehensive improvement effect of degree is better.

It should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit other forms of the present invention. Any skilled person who is familiar with this field may use the above-mentioned technical content as inspiration to change or remodel to an equivalent For the equivalent embodiments of changes, as long as they do not deviate from the technical essence of the claims of the present invention, the simple modifications, equivalent changes and modifications made to the above embodiments still belong to the protection scope of the claims of the present invention.

Claims

An auxiliary fermentation agent is characterized in that it comprises Streptococcus thermophilus JMCC0031 and Streptococcus thermophilus JMCC0032 with a ratio of viable bacteria number of 1:0.5-2.
A kind of auxiliary starter according to claim 1, characterized in that, the ratio of the number of viable bacteria is 1:1.
An application of an auxiliary starter as claimed in claim 1 or 2, characterized in that it is used to prepare yogurt by fermenting milk or reconstituted milk after it is compounded with a conventional yogurt starter.
The application of a kind of auxiliary starter according to claim 3, characterized in that, the compounding is combining auxiliary starter and conventional yogurt starter in a mass ratio of 1:1-3.
The application of a kind of auxiliary starter according to claim 3 or 4, characterized in that, said conventional yogurt starter is yogurt composite starter JLB-1510.