CN115960778B - Fermented lactobacillus mucilaginosus and application thereof in regulating flavor of rice products - Google Patents

Abstract

The present invention discloses a strain of fermented mucus lactobacillus and its application in regulating the flavor of rice products. The fermented lactobacillus (Limosilactobacillusfermentum FR‑21) was preserved in the China Type Culture Collection of Wuhan University on November 2, 2022, and its number is CCTCC No: M20221709. When applied to fermented rice products, the fermentation container is first pasteurized, and then the fermented mucus lactobacillus (Limosilactobacillusfermentum FR‑21) is inoculated, the inoculation amount is 10 ⁶ ~ 10 ⁸ cfu/mL, and the micro-fermentation is 6 to 60h at 30 to 40°C. The obtained rice product flavor is evaluated as fermentation aroma by electronic nose test combined with sensory evaluation, and GC‑MS analysis shows that the flavor is a fermentation aroma with aldehydes of 5 to 10 carbon atoms and/or alcohols as the main components. The use of the fermented mucus lactobacillus (Limosilactobacillusfermentum FR-21) can be directly administered or made into liquid, powder, tablet, or capsule for application.

Description

A strain of fermented Lactobacillus mucilaginosus and its application in regulating the flavor of rice products

Technical Field

The invention belongs to the technical field of microbial fermentation, and particularly relates to a fermented mucus lactobacillus strain and application thereof in regulating the flavor of rice products.

Background technique

Fermented rice products refer to foods with unique flavors prepared by fermenting rice with microorganisms. Usually, rice is soaked and fermented for a period of time, and processed into different forms of food, such as fresh wet rice noodles, rice cakes, rice steamed buns, rice dumplings, etc. However, the quality of natural soaking and fermentation products of rice is unstable, especially in hot summer weather, and it is easy to produce odors such as sour smell and odor; when the dominant bacteria have not yet formed, it is also difficult to obtain products with stable flavor. Research reports show that adding lactobacillus can improve the quality of fermented rice products. For example, Chinese invention patent CN104886459A discloses a method for making fermented rice flour, which uses natural fermentation liquid as the fermentation liquid stock liquid, adds a mixed bacterial liquid including fermented lactobacillus, salivarius, plant lactobacillus and yeast for fermentation, and obtains a method for making fermented rice flour with a fermented aroma that can be processed into rice products such as rice noodles and rice cakes. However, this method adopts a mixed fermentation mode of different bacteria, and the volatile flavor substances of the obtained product are unclear, and the stability of the quality is difficult to control. Chinese invention patent CN108165502A discloses a strain of plant lactobacillus for improving the flavor of fresh wet rice noodles, which can make rice noodles (lines) form pure rice fragrance, solving the problem of unstable flavor quality of fresh wet rice noodles in newly built rice noodles (lines) factories and the generation of peculiar smells such as sour smell and odor in rice noodles during high temperature seasons. However, the fragrance of rice products made by this method cannot meet the diversified needs of the market. Chinese invention patent CN103352014A discloses a strain of fermented lactobacillus LG1, which is used to solve the problems of long cycle and easy corruption of traditional fermentation process, and improves the nutritional content of yellow rice. However, this method does not involve the improvement of product flavor after fermentation.

With the improvement of living standards, the fermented rice product industry has higher and higher requirements for product flavor. Providing a rice product with unique flavor, relatively stable volatile flavor substances and convenient processing can better meet the needs of the market.

Summary of the invention

The invention aims to provide a fermented mucus lactobacillus strain, which can form a unique fermented aroma of rice products through fermentation, and solve the problem that the flavor of rice products is not prominent and unstable.

In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: a strain of fermented mucus lactobacillus is screened, characterized in that the fermented mucus lactobacillus (Limosilactobacillus fermentum FR-21) was preserved in the China Type Culture Collection of Wuhan University on November 2, 2022, and its number is CCTCC No: M20221709, which can make fermented rice products produce a stable fermentation aroma.

The invention also relates to the application of the fermented mucus lactobacillus (Limosilactobacillusfermentum FR-21) in regulating the flavor of rice products.

Furthermore, the raw material of the rice product is indica rice.

Furthermore, the fermented Lactobacillus fermentum FR-21 is used in regulating the flavor of rice products by directly adding the fermented Lactobacillus fermentum FR-21 into raw materials for fermentation to prepare fermented rice. The specific steps include:

S1. Container sterilization: pasteurize the fermentation container;

S2. Inoculation of bacteria: placing the raw materials into a container and inoculating the bacteria;

S3. Micro-fermentation: controlling the fermentation temperature of the raw materials after inoculation of the bacteria, micro-fermentation for a period of time to obtain fermented rice;

S4. Preparation of rice products: The fermented rice is washed, ground/milled, matured and molded to obtain the rice product with fermented flavor.

Furthermore, the sterilization method is pasteurization, the inoculation amount of fermented Lactobacillus fermentum FR-21 is 10 ⁶ to 10 ⁸ cfu/mL, the fermentation temperature is 30 to 40° C., and the fermentation time is 6 to 60 hours.

Furthermore, the fermentation temperature is 37°C and the fermentation time is 48h.

Furthermore, the fermentation bacteria are directly administered or made into liquid, powder, tablet or capsule for application.

Furthermore, the use of the above-mentioned fermented mucus lactobacillus (Limosilactobacillusfermentum FR-21) is applied to the product prepared by fermenting indica rice, and its flavor is fermentation aroma through electronic nose test combined with sensory evaluation; GC-MS analysis shows that the fermentation aroma in the rice product comes from aldehydes and/or alcohols with 5 to 10 carbon atoms.

The invention has the advantages that the rice product prepared by fermentation with the fermented mucus lactobacillus has a pure and unique fermentation aroma and stable volatile flavor substances.

Detailed ways

The present invention provides fermented mucus lactobacillus (Limosilactobacillusfermentum FR-21) and its application in regulating the flavor of rice products. Those skilled in the art can refer to the content of this patent and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application of this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

Example 1

This embodiment provides a method for preparing fresh wet rice noodles using fermented mucus lactobacillus (Limosilactobacillusfermentum FR-21), and the specific steps include:

(1) Raw material preparation:

The fermentation tanks were carefully cleaned and pasteurized at 70°C;

Weigh 3 kg of indica rice Zhefu 802 raw material and put it into a sterilized fermentation tank;

Limosilactobacillusfermentum FR-21 is ready for use.

(2) Preparation of fermented rice:

Add 1.2 times (by mass) of distilled water to the indica rice Zhefu 802 raw material weighed in step (1), and inoculate the prepared fermented mucus lactobacillus (Limosilactobacillusfermentum FR-21) at 10 ⁸ cfu/mL;

The inoculated indica rice was fermented at 37° C. for 48 hours to obtain fermented rice.

(3) Preparation of fresh wet rice flour:

The product obtained in step (2) is cleaned, ground, steamed, extruded, boiled, re-steamed and washed to obtain fresh wet rice noodles.

(4) Fragrance evaluation and data characterization:

The aroma is evaluated by combining sensory evaluation and flavor component analysis.

Sensory evaluation methods include a combination of electronic nose and manual evaluation.

The flavor of the fresh wet rice noodles prepared in this example was evaluated as fermentation aroma by electronic nose and sensory evaluation.

The fresh wet rice noodles prepared in this example were analyzed for volatile substances by GC-MS. The results are shown in Table 1.

In Table 1, the volatile organic substances are mainly aldehydes with 5 to 10 carbon atoms, 1-nonanol and acetic acid, which are the sources of the fermentation aroma in this embodiment.

Specifically, in this embodiment, aldehydes account for 54% and alcohols account for 33%.

Table 1 Volatile compound content of fresh wet rice noodles (Limosilactobacillusfermentum FR-21 fermentation)

Example 2

This embodiment provides a method for preparing rice dumpling wrappers using fermented mucus lactobacillus (LimosilactobacillusfermentumFR-21), and the specific steps include:

(1) Raw material preparation:

The fermentation tanks were carefully cleaned and pasteurized at 70°C;

Weigh 3 kg of indica rice Zhefu 802 raw material and put it into a sterilized fermentation tank;

The fermented Lactobacillus fermentum FR-21 is ready for use.

(2) Preparation of fermented rice:

Add 1.1 times (by mass) of distilled water to the indica rice Zhefu 802 raw material weighed in step (1), and inoculate the prepared fermented mucus lactobacillus (LimosilactobacillusfermentumFR-21) at 10 ⁷ cfu/mL;

The inoculated indica rice was fermented at 30°C for 24 hours to obtain fermented rice.

(3) Preparation of rice dumpling wrappers:

The product obtained in step (2) is cleaned, ground, steamed, rolled, pressed and formed to obtain rice dumpling wrappers.

(4) Fragrance evaluation and data characterization:

The aroma is evaluated by combining sensory evaluation and flavor component analysis.

Sensory evaluation methods include a combination of electronic nose and manual evaluation.

The flavor of the rice dumpling wrapper prepared in this example was evaluated as yeast aroma by electronic nose and sensory evaluation.

The rice dumpling wrapper prepared in this example was analyzed for volatile substances by GC-MS. The results are shown in Table 2.

In Table 2, the volatile organic substances are mainly aldehydes with 5 to 10 carbon atoms and 1-nonanol, which are the sources of the fermentation aroma of this embodiment.

Specifically, in this embodiment, aldehydes account for 52% and alcohols account for 39%.

Table 2 Volatile compound content of rice dumpling wrappers (LimosilactobacillusfermentumFR-21 fermentation)

Example 3

This embodiment provides a method for preparing steamed rice cake using fermented Lactobacillus fermentum FR-21, the specific steps comprising:

(1) Raw material preparation:

The fermentation tanks were carefully cleaned and pasteurized at 70°C;

Weigh 3 kg of indica rice Zhefu 802 raw material and put it into a sterilized fermentation tank;

Limosilactobacillusfermentum FR-21 is ready for use.

(2) Fermented rice preparation:

The indica rice in step (1) was inoculated with 10 ⁶ cfu/mL of fermented Lactobacillus fermentum FR-21, with a solid-liquid ratio of 6:5, fermented at 35° C. for 6 hours, washed, and ground to obtain fermented rice flour.

(3) Fermented rice cake preparation:

The fermented rice flour obtained in step (2) is molded, proofed, and steamed to obtain a steamed rice cake.

(4) Fragrance evaluation and data characterization:

The aroma is evaluated by combining sensory evaluation and flavor component analysis.

Sensory evaluation methods include a combination of electronic nose and manual evaluation.

The flavor of the steamed rice cake prepared in this example was evaluated as yeast aroma by electronic nose and sensory evaluation.

The volatile substances in the steamed rice cake powder prepared in this example were analyzed by GC-MS. The results are shown in Table 3.

In Table 3, the volatile organic substances are mainly aldehydes and alcohols with 5 to 10 carbon atoms and acetic acid, which are the source of the fermentation aroma of this embodiment.

Specifically, in this embodiment, aldehydes account for 32%, alcohols account for 34%, and acetic acid accounts for 18%.

Table 3 Volatile compound content of rice cake (Limosilactobacillusfermentum FR-21 fermentation)

In summary, in Examples 1, 2, and 3, the steps of: S1. container sterilization, S2. strain inoculation, S3. micro-fermentation, and S4. rice product preparation are performed. The fermented rice products finally obtained are analyzed by GC-MS, which shows that the flavor is mainly aldehydes and alcohols with 5 to 10 carbon atoms, wherein the detected aldehydes mainly include hexanal, nonanal, etc., and the detected alcohols mainly include n-hexanol, 1-nonanol, n-pentanol, etc. These volatile organic compounds account for 60 to 90%, and when mixed together, they emit a fermented aroma.

In the present invention, fermented rice products are prepared by inoculating fermented mucus lactobacillus (Limosilactobacillusfermentum FR-21), and the obtained product has a pure and unique fermented aroma. In the preparation process, the volatile flavor substances of the obtained fermented rice products can be stabilized by controlling the inoculation amount of the strain, the fermentation time and the fermentation temperature.

Claims (10)

1. Lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 with a preservation number of CCTCC No: m20221709.

2. Use of lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 as claimed in claim 1 for regulating the flavour of rice products.

3. Use of lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 according to claim 2 for regulating the flavour of rice products, wherein the raw material of said rice products is indica rice.

4. The use of lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 according to claim 2 for regulating the flavor of rice products, wherein the lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 is directly added into raw materials for fermentation to prepare fermented rice.

5. Use of lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 according to any of claims 2 to 4 for the regulation of rice product flavour, characterized in that: the preparation method of the rice product comprises the following specific steps:

S1, sterilizing a container: pasteurizing the fermentation vessel;

S2, inoculating strains: placing the raw materials into a container, and inoculating strains;

S3, fermenting: controlling the fermentation temperature of the raw materials after the inoculation of the strain, and fermenting for a period of time to obtain fermented rice;

s4, rice preparation: the fermented rice is subjected to cleaning, pulping, curing and forming to obtain the rice product with the fermenting flavor.

6. Use of lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 according to claim 5 for modulating the flavour of rice products, characterized in that: the inoculation amount of the fermentation lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 is 10 ⁶～10⁸ cfu/mL, the fermentation temperature is 30-40 ℃, and the fermentation time is 6-60 h.

7. Use of lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 according to claim 2 or 3 for regulating the flavour of rice products, characterized in that: the fermentation lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 is directly applied or is prepared into liquid, powder, tablets or capsules.

8. The use of lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 according to claim 6 for the regulation of the flavour of rice products, characterized in that: the fermentation temperature is 37 ℃, and the fermentation time is 48 h.

9. Use of lactobacillus mucilaginosus (Limosilactobacillus fermentum) FR-21 according to any of claims 2 to 4 for the regulation of rice product flavour, characterized in that: the rice product contains aldehydes and/or alcohols with 5-10 carbon atoms.

10. A rice product fermented with the lactobacillus mucilaginosus (Limosilactobacillus fermentum FR-21) according to claim 1; the rice product is selected from one of fresh wet rice flour, rice cake, rice steamed bread, and rice dumpling wrapper.