CN114369546A

CN114369546A - Pediococcus acidilactici, fermentation microbial inoculum and application thereof, and preparation method of coarse cereal fermented food

Info

Publication number: CN114369546A
Application number: CN202111640195.2A
Authority: CN
Inventors: 杨学昊; 李慧; 张连慧; 钟鸣; 任海斌; 杨海莺; 朱峰华
Original assignee: Cofco Corp; Cofco Nutrition and Health Research Institute Co Ltd
Current assignee: Cofco Corp; Cofco Nutrition and Health Research Institute Co Ltd
Priority date: 2021-12-29
Filing date: 2021-12-29
Publication date: 2022-04-19
Anticipated expiration: 2041-12-29
Also published as: CN114369546B

Abstract

The invention relates to the field of food fermentation, and discloses pediococcus acidilactici, a fermentation microbial inoculum, application thereof and a preparation method of coarse cereal fermented food. The coarse cereal fermented food prepared by fermenting the pediococcus acidilactici provided by the invention has improved taste and nutrient component structure, longer quality guarantee period and unique fermentation flavor, and is beneficial to the development of the coarse cereal food market.

Description

Pediococcus acidilactici, fermentation microbial inoculum and application thereof, and preparation method of coarse cereal fermented food

Technical Field

The invention relates to the field of food fermentation, in particular to pediococcus acidilactici, a fermentation microbial inoculum, application thereof and a preparation method of coarse cereal fermented food.

Background

With the improvement of social and economic levels, the requirements of people on food are continuously improved, and the aspects of health, nutrition, safety and the like of the food are more and more valued by consumers. In coarse cereals, the contents of components such as proteins, vitamins, minerals and cellulose are higher than those of "fine rice noodles", and the proportions of the respective nutritional components are reasonable, so that consumers have attracted much attention in recent years. However, the coarse cereals have rough mouthfeel, and the coarse cereals contain anti-nutritional factors such as phytic acid and the like, so that the coarse cereals are not easy to digest and absorb, and the development of coarse cereal foods is limited.

In the preparation process of the fermented food, the chemical structure of nutrient substances in the raw materials is changed under the action of the zymophyte, so that the cooking quality of the fermented food is changed, and the taste and the composition proportion of nutrient components of the food can be changed. The preparation of the related food by fermenting the coarse cereals can effectively avoid the defects of the coarse cereal food. However, the fermentation strains commonly used at present are generally selected and bred based on the preparation of conventional foods, and the fermentation efficiency and the effect of the fermentation strains are not ideal when coarse cereals with different nutrient contents from common white noodles are fermented. Therefore, the development of special strains aiming at the characteristics of the coarse cereal food is urgently needed to meet the needs of the coarse cereal food market.

Disclosure of Invention

The invention aims to solve the problems that coarse cereal food in the prior art is poor in taste and nutrition absorption effect, a fermentation strain specially used for production of coarse cereal food is lacked, and the like, and provides a pediococcus acidilactici strain, a fermentation microbial inoculum, application of the fermentation microbial inoculum and a preparation method of the coarse cereal fermented food. The pediococcus acidilactici provided by the invention can effectively degrade phytic acid and is suitable for production of coarse cereal foods, and the coarse cereal fermented foods prepared by adopting the pediococcus acidilactici also have unique fermentation flavor.

In order to achieve the aim, the invention provides a Pediococcus acidilactici (Pediococcus acidilactici) strain, and the preservation number of the Pediococcus acidilactici is CGMCC No. 21160.

The second aspect of the invention provides a fermentation inoculant, which contains pediococcus acidilactici.

The third aspect of the invention provides the application of pediococcus acidilactici or the zymocyte agent in preparing the coarse cereal fermented food.

The invention provides a preparation method of coarse cereal fermented food, which comprises the step of mixing coarse cereal raw materials with pediococcus acidilactici or a zymophyte agent for fermentation.

The fifth aspect of the invention provides the coarse cereal fermented food prepared by the method.

Through the technical scheme, the invention can obtain the following beneficial effects:

(1) the pediococcus acidilactici provided by the invention has a wide temperature application range and strong acid production capacity, so that the pediococcus acidilactici can be suitable for fermentation of different types of coarse cereals and has the potential of large-scale industrial production and application;

(2) the pediococcus acidilactici provided by the invention can effectively degrade phytic acid, so that the problems of high phytic acid content and poor nutrition absorption effect in coarse cereal foods are solved, the nutritional requirements of consumers on the coarse cereal foods can be met, and the development of the coarse cereal food market is facilitated;

(3) the coarse cereal fermented food prepared by pediococcus acidilactici provided by the invention has good taste, unique flavor and longer shelf life, and is more beneficial to popularization and development of coarse cereal foods;

(4) the pediococcus acidilactici provided by the invention can also shorten the cooking time of coarse cereals, thereby improving the production efficiency of coarse cereal fermented food and improving the economic benefits of enterprises.

Drawings

FIG. 1 is a colony morphology of Pediococcus acidilactici provided by the present invention;

FIG. 2 is a microscopic morphology of Pediococcus acidilactici provided by the present invention.

Biological preservation

The Pediococcus acidilactici provided by the invention is preserved in China general microbiological culture Collection center (CGMCC) at 11 months and 11 days in 2020, the preservation number is CGMCC No.21160, and the address is No. 3 of West Lu No. 1 of Beijing Korean district.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In the research process, the inventor of the invention separates and obtains Pediococcus acidilactici (Pediococcus acidilactici) from the natural fermented yogurt of Tibetan lucid ganoderma, and further researches show that the Pediococcus acidilactici strain has a wider temperature adaptation range, is strong in acid production capacity, can effectively degrade phytic acid, and can improve the taste and the nutritional structure of coarse cereals, shorten the cooking time and prolong the shelf life when being used for fermenting the coarse cereals. The strain is preserved in China general microbiological culture Collection center (CGMCC) at 11/2020 with the preservation number of CGMCC No. 21160.

On one hand, the invention provides a Pediococcus acidilactici strain, and the preservation number of the Pediococcus acidilactici strain is CGMCC No. 21160.

The content of pediococcus acidilactici in the fermentation inoculum provided by the invention is not particularly limited. Advantages according to the inventionIn an embodiment, the content of Pediococcus acidilactici in the fermentation inoculum is 10 in terms of viable count¹⁰CFU/g is higher than the standard. Said "10¹⁰CFU/g' means that the content of pediococcus acidilactici in the zymophyte agent reaches 10 orders of magnitude¹⁰E.g. 1X 10¹⁰CFU/g、5×10¹⁰CFU/g、9.9×10¹⁰CFU/g, etc. all belong to the category of "10¹⁰Order of magnitude level ".

Preferably, the content of the pediococcus acidilactici is 10¹¹-10¹²CFU/g。

The fermentation starter provided by the invention can be any type of microbial inoculum existing in the field. Such as solid (powder) inocula, liquid inocula, semi-liquid inocula, concentrated inocula, etc.

According to a preferred embodiment of the present invention, the fermentation inoculum may further comprise an auxiliary material.

Preferably, the excipient is selected from a lyoprotectant and/or a stabilizer.

More preferably, the lyoprotectant is selected from at least one of skim milk powder, maltodextrin, trehalose, dextran, and glycerol.

More preferably, the stabilizer is selected from at least one of skim milk powder, trehalose, and glycerin.

The fermentation inoculum provided by the invention can be prepared by any existing inoculum preparation method in the field. According to a preferred embodiment of the present invention, the preparation method of the fermentation inoculum may include the following steps:

(1) culturing Pediococcus acidilactici CGMCC No.21160 in a culture medium to ensure that the viable count reaches 10⁸And (5) more than CFU/mL to obtain the liquid fermentation inoculum.

(2) Mixing the liquid fermentation inoculum with fermentation substrate to make viable count reach 10⁵And (5) more than CFU/mL to obtain the semi-liquid fermentation inoculum.

(3) And concentrating the liquid fermentation inoculum to obtain a concentrated fermentation inoculum.

(4) And separating to obtain pediococcus acidilactici in the liquid fermentation inoculum, and drying to obtain the solid fermentation inoculum.

Preferably, in the method (1), the culture medium may be any medium existing in the art for culturing pediococcus acidilactici, such as MRS medium, MC medium, and the like. It is either commercially available or self-formulated according to the prior art.

Preferably, in the liquid fermentation microbial inoculum, the content of pediococcus acidilactici is 10 in terms of viable count⁶-10⁷CFU/mL。

Preferably, in the method (2), the fermentation substrate is selected from flour and/or (mixed) coarse cereal flour. More preferably, the fermentation substrate contains coarse cereals (i.e. more preferably (mixed) coarse cereal powder), and the content of the coarse cereals is preferably 10-80 wt% of the total weight of the fermentation substrate.

In the method (3), the concentration may be carried out by any concentration means known in the art. Preferably, the concentration may be performed by at least one of centrifugation, membrane separation and sedimentation.

Preferably, the content of the pediococcus acidilactici in the concentrated zymophyte agent is 10 counted by the number of live bacteria¹⁰CFU/mL or more. More preferably 10¹¹-10¹²CFU/mL。

The method (4) can be carried out by any method conventionally used in the art for separating cultured cells from a liquid medium. Preferably, the separation of the pediococcus acidilactici cells is performed by centrifugation.

Any conditions for centrifugation of cells known in the art can be applied to the present invention. According to a preferred embodiment of the present invention, wherein the centrifugation conditions may include: the temperature is 1-10 ℃, the rotation speed is 5000-.

Preferably, the separated pediococcus acidilactici cells may be mixed with an auxiliary material (e.g., a lyoprotectant) before the drying treatment. Preferably, the ratio of the auxiliary material to the pediococcus acidilactici is 1: mixing at a volume ratio of 1-10.

More preferably, the pediococcus acidilactici cells are washed with a buffer solution before being mixed with the auxiliary materials. The buffer may be any buffer known in the art for cell washing, such as physiological saline, PBS buffer, and the like. The washing operation may be repeated a plurality of times, for example, 3 to 5 times, in order to thoroughly wash the remaining culture medium.

Preferably, the drying may be performed in a freeze-drying manner.

More preferably, the conditions of the lyophilization and drying may include: the temperature is between 25 ℃ below zero and 75 ℃ below zero, the time is 12 to 22 hours, and the water content of the dried fermentation inoculum is preferably not more than 5 weight percent.

According to a preferred embodiment of the invention, other lactic acid bacteria can be added into the fermentation microbial inoculum to achieve the purposes of obtaining better fermentation effect, improving the flavor of the fermented food, improving the texture and mouthfeel and the like.

Any lactic acid bacteria known in the art for use in the preparation of fermented foods may be suitable for use in the present invention. Preferably, the lactic acid bacteria may be selected from at least one of lactobacillus, lactococcus, bifidobacterium and pediococcus acidilactici.

In the invention, the coarse cereal fermented food is prepared by fermenting raw materials containing coarse cereals and then cooking. The content of the minor cereals in the raw materials is preferably 10 wt% or more.

Any coarse cereal used for food preparation in the field can be suitable for the method provided by the invention. According to a preferred embodiment of the present invention, the coarse cereals in the coarse cereal raw material are selected from at least one of red beans, mung beans, barley, sorghum, corn, millet, oat and coix seeds.

The method provided by the invention can be used for preparing any type of coarse cereal fermented food in the field. According to a preferred embodiment of the present invention, the coarse cereal fermented food is selected from at least one of coarse cereal noodles, coarse cereal steamed bread and coarse cereal bread.

In the method provided by the invention, the coarse cereal raw material is a food raw material taking coarse cereals as (one of) main components, and the coarse cereal raw material can be a food raw material only containing coarse cereals or a mixture of coarse cereals and refined grains (such as rice, flour and the like), and the content of coarse cereals in the coarse cereal raw material is not particularly limited. According to a preferred embodiment of the present invention, the coarse cereal raw material is flour (wheat flour) containing coarse cereals, wherein the content of the coarse cereals is 10 wt% or more, preferably 10-80 wt%.

Preferably, the content of the coarse cereals in the coarse cereal raw material is 20-50 wt%.

In the method provided by the invention, the dosage of the pediococcus acidilactici or the zymogen is not particularly limited, and can be adjusted according to actual conditions. In order to obtain better fermentation effect, improve fermentation efficiency and improve quality performance of fermented products, according to a preferred embodiment of the invention, the dosage of pediococcus acidilactici or the fermentation inoculant enables the initial content of pediococcus acidilactici in a fermentation system to be 10⁵-10⁶CFU/mL. The fermentation system refers to a system for fermenting after mixing coarse cereal raw materials, water and pediococcus acidilactici (or zymophyte agent).

Preferably, the conditions of the fermentation include: the temperature is 10-45 ℃, and the pH is 4-8.

The method provided by the invention also comprises the step of processing the fermented coarse cereal raw materials to prepare different kinds of coarse cereal fermented foods after the fermentation is finished. This treatment step may be carried out by any method known in the art.

The present invention will be described in detail below by way of examples. It should be understood that the following examples are only intended to further illustrate and explain the contents of the present invention by way of example, and are not intended to limit the present invention.

In the following examples, the chemical reagents used were purchased from a normal chemical supplier unless otherwise specified.

The media formulations referred to in the following examples are as follows:

MRS culture medium: peptone 1 wt%, beef powder 0.5 wt%, yeast powder 0.4 wt%, glucose 2 wt%, Tween 800.1 wt%, and K₂HPO₄.7H₂0.2% by weight of O, sodium acetate 3H₂0.5% by weight of O, 0.2% by weight of triammonium citrate, MgSO₄·7H₂0.02 wt.% of O, MnSO₄·4H₂O0.005% by weight. Weighing the reagents according to the above dosage, dissolving in deionized water, adjusting pH to 6.2 + -0.2, and autoclaving at 121 deg.C for 15-20min to obtain liquid MRS culture medium. Adding agar powder 1.5 wt% before sterilization, then autoclaving at 121 deg.C for 15-20min, cooling and solidifying to obtain solid MRS culture medium.

And (3) cooling the sterilized solid MRS culture medium to be not scalded (about 50 ℃), pouring the solid MRS culture medium into a culture dish, and cooling and solidifying to obtain the MRS culture plate.

MC culture medium: 0.5 weight percent of soybean peptone, 0.3 weight percent of beef powder, 0.3 weight percent of yeast powder, 2 weight percent of glucose, 2 weight percent of lactose and 1 weight percent of calcium carbonate. Weighing the reagents according to the above dosage, dissolving in deionized water, adjusting pH to 6.0 + -0.2, adding 1% neutral red solution 0.5 wt%, and autoclaving at 121 deg.C for 15-20min to obtain liquid MC culture medium. Adding agar 1.5 wt% before sterilization, autoclaving at 121 deg.C for 15-20min, cooling and solidifying to obtain solid MC culture medium.

And (3) cooling the sterilized solid MC culture medium to be not scalded (about 50 ℃), pouring the solid MC culture medium into a culture dish, and cooling and solidifying to obtain the MC culture plate.

Example 1

This example illustrates the isolation, purification, identification and preservation of Pediococcus lactis.

The inventor separates and obtains a lactic acid bacteria strain from natural fermented yoghourt of Tibetan Linzhi, and purifies the lactic acid bacteria strain for three times by a streaking separation and purification method to obtain a plurality of single pure bacterial colonies.

Morphological identification: the purified lactobacillus strains were cultured using MRS plates and the colony morphology was observed (as shown in fig. 1).

The lactic acid bacteria strain was cultured in a liquid MRS medium, and the morphology of the cells was observed with a microscope (as shown in FIG. 2).

16S-ITS rDNA gene sequencing and identification: the purified total DNA of lactic acid bacteria (extracted using DNA extraction kit (DP302) from Tiangen Biochemical technology Ltd. according to the instructions) was used as a template, and 27F (5'-AGAGCCTGGCTCAGTTTGAT-3', SEQ ID NO:1) and 1492R (5'-GGTTACCTTGTTACGACTT-3', SEQ ID NO:2) were used as a forward primer and a reverse primer, respectively, to perform ITS rDNA amplification according to the PCR system in Table 1 and the amplification procedure in Table 2.

TABLE 1

Reagent	Volume/. mu.L
		10×PCR Buffer	3
dNTPs	2.5
		Forward primer (27F)	1.5
Reverse primer (1492R)	1.5
		Template DNA	2
Taq DNA polymerase (5U/. mu.L)	0.3
		dd H2O	19.2
Total volume	30

TABLE 2

The amplification product was sent to Weijie Shanghai trading Co., Ltd for sequencing, and the results are shown below:

GCTTGCACTGAATGAGATTTTAACACGAAGTGAGTGGCGGACGGGTGAGTAACACGTGGGTAACCTGCCCAGAAGCAGGGGATAACACCTGGAAACAGATGCTAATACCGTATAACAGAGAAAACCGCCTGGTTTTCTTTTAAAAGATGGCTCTGCTATCACTTCTGGATGGACCCGCGGCGCATTAGCTAGTTGGTGAGGTAACGGCTCACCAAGGCGATGATGCGTAGCCGACCTGAGAGGGTAATCGGCCACATTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTAGGGAATCTTCCACAATGGACGCAAGTCTGATGGAGCAACGCCGCGTGAGTGAAGAAGGGTTTCGGCTCGTAAAGCTCTGTTGTTAAAGAAGAACGTGGGTGAGAGTAACTGTTCACCCAGTGACGGTATTTAACCAGAAAGCCACGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGTGGCAAGCGTTATCCGGATTTATTGGGCGTAAAGCGAGCGCAGGCGGTCTTTTAAGTCTAATGTGAAAGCCTTCGGCTCAACCGAAGAAGTGCATTGGAAACTGGGAGACTTGAGTGCAGAAGAGGACAGTGGAACTCCATGTGTAGCGGTGAAATGCGTAGATATATGGAAGAAAACAAGTGGCGAAGGCGGCTGTCTGGTCTGTAACTGACGCTGAGGCTCGAAAGCATGGGTAGCGAACAGGATTAGATACCCTGTTAGTACCCTGCTGTCAACGATAAGAGTGATTACTAAGTGTTGGAGGGTTTCCGCCCTTCAGTGCTGCAGCTAACGCATTAAGTTATCCGCCTGGGGAGTACGACCGCAAGGTTGAAACTCAAAGAATTGACGGGGGCCGCACAAGCGTGGAGCATGTGGTTAATTCGAAGTACGCGAAGAACTTACCAGGTCTTGACATCTTTGCCAACCTAAGAGATTAGGCGTTCCCTTTCGGGGACAGAATGACAGGTGGTGCATGGTTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTATTACTAGTTGCCAGCATTCAGTTGGGCACTCTAGTGAGACTGCCGGTGACAAACCGGAGGAAGGTGGGGACGACGTCAAATCATCATGCCCCTTATGACCTGGGCTACACACGTGCTACAATGGATGGTACAACGAGTTGCGAAACCGCGAGGTTTAGCTAATCTCTTAAAACCATTCTCAGTTCGGACTGTAGGCTGCAACTCGCCTACACGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGCCGCGGTGAATACGTTCCCGGGCCTTGTACACACCGCC(SEQ ID NO:3)

the strain is identified as Pediococcus acidilactici (Pediococcus acidilactici) by combining the morphological and biochemical identification results.

The strain is preserved in China general microbiological culture Collection center (CGMCC) on 11 months and 11 days in 2020, the preservation number is CGMCC No.21160, and the address is as follows: xilu No. 1 Hospital No. 3, Beijing, Chaoyang, North.

Example 2

This example is used to illustrate the temperature adaptability and acid-producing capability of Pediococcus acidilactici CGMCC No.21160

Preparing a pediococcus acidilactici bacterial suspension: inoculating Pediococcus acidilactici CGMCC No.21160 into MC culture medium, and culturing at 30 deg.C for 6 hr until viable count reaches 10¹⁰-10¹²CFU/mL to obtain pediococcus acidilactici suspension.

Processing a coarse cereal sample: washing coarse cereals (prepared by mixing oat, pea and hyacinth bean at a weight ratio of 1: 1.5: 2.5) with 3 wt% hydrogen peroxide water solution for 3 times, each time for 10min, and sterilizing to obtain sterilized coarse cereal samples.

Mixing the disinfected coarse cereal sample with sterile water according to the weight ratio of 1:1.5 +/-0.3, and adding the pediococcus acidilactici bacterial suspension according to the volume ratio of 1:1. Fermenting and culturing in constant-temperature incubators of 10 ℃, 15 ℃, 20 ℃, 30 ℃, 35 ℃ and 45 ℃, respectively, measuring the pH value of the fermented coarse cereals every 3 hours, stopping culturing when the pH value of the fermented coarse cereals is lower than 4, and evaluating the acid production capacity of pediococcus acidilactici CGMCC No.21160 under different temperature conditions. The results are detailed in Table 3.

TABLE 3

As can be seen from Table 3, the pH of the fermented coarse cereals can reach below 4 within 24h at 10-45 ℃ by pediococcus acidilactici CGMCC No.21160, which shows that the strain has wide temperature range and strong acid-producing capability.

Example 3

The embodiment is used for explaining the influence of pediococcus acidilactici CGMCC No.21160 on the degradation, appearance integrity and taste of phytic acid in coarse cereals.

The coarse cereal samples (specific species are detailed in table 4) were treated and fermented according to the method in example 2, and the specific fermentation conditions were as follows: the temperature is 30 ℃ and the time is 2 h. Obtaining the fermented coarse cereals.

Drying the fermented coarse cereals (75 ℃, 4h), and comparing the phytic acid content of different fermented coarse cereals with the acceptance of the cooked mouthfeel (hardness). The results are detailed in Table 4.

Blank control group: unfermented coarse cereals

Positive control group: coarse cereals fermented by commercial Pediococcus lactis (from Angel Yeast Co., Ltd.)

Experimental groups: coarse cereals fermented by pediococcus acidilactici CGMCC No.21160

The phytic acid content detection method comprises the following steps: 1g of the sample was weighed into a 50mL beaker, and 1mL of concentrated sulfuric acid (98%) and 3mL of concentrated nitric acid (68% concentration) were added thereto, digested, cooled, and then added to a 50mL volumetric flask, diluted to the scale with distilled water, to obtain a digested sample solution. The same amount of sample was added to a 50mL volumetric flask and distilled water was added to the scribed line to obtain a control sample solution. 1mL of the digestion sample and the control sample solution were added to a 50mL volumetric flask, and 5mL of the ammonium molybdate-sulfuric acid standard solution was added thereto, and distilled water was added to the reticle. Heating in water bath at 45 deg.C for 30min, cooling, and detecting light absorption value at 660 nm. And (3) checking the light absorption value difference value of the digestion treatment sample and the control sample on a potassium dihydrogen phosphate standard curve to obtain the corresponding phosphorus content which is the phytic phosphorus content, and multiplying by 3.548 to obtain the phytic acid content.

TABLE 4

As can be seen from Table 4, the pediococcus acidilactici CGMCC No.21160 fermented corn, barley, oat and other coarse cereals can degrade phytic acid therein, and the degradation rate of the phytic acid reaches more than 50 percent, which is higher than that of commercial lactic acid bacteria. The hardness after cooking is moderate, which shows that the pediococcus acidilactici provided by the invention has the potential of preparing the coarse cereal fermented food with nutritional ingredients and taste meeting the needs of consumers.

Example 4

This example illustrates the sensory quality of the product when the pediococcus acidilactici CGMCC No.21160 is used to prepare the coarse cereal steamed bread.

Preference test

The adopted preparation method of the coarse cereal powder comprises the following steps: stacking washed highland barley, wetting to make the hull layer absorb water for 3-5h, pulverizing in a pulverizer, and sieving with 80 mesh sieve.

The preparation method of the coarse cereal steamed bread comprises the following steps: mixing coarse cereal flour, wheat flour and water according to the weight ratio of 1: 1:1, and adding the pediococcus acidilactici suspension prepared in example 2 to make the content of the pediococcus acidilactici CGMCC No.21160 about 10³-10⁵CFU/mL. Stirring in a dough mixer for 8-10min, shaping dough (130 g per dough) into blocks, proofing at 35 deg.C and relative humidity of 80% for 1.5 hr, taking out, secondary shaping, proofing under the same conditions for 40min, and steaming for 25 min.

The characteristics of the air hole distribution of the coarse cereal steamed bread are observed, and the air holes are found to be fine and uniform, so that the coarse cereal steamed bread is softer in taste and quick in resilience.

The preference degree of the coarse cereal steamed bread is tested, and detection indexes comprise color, flavor, wetness, elasticity and integral preference degree. The result shows that the coarse cereal steamed bread has the characteristics of high wettability, quick resilience, softness, refreshing taste, no tooth adhesion, prominent lactic acid fragrance and the like.

(II) shelf life detection

The same procedure was used to prepare a cereal steamed bread using commercially available lactic acid bacteria (available from Angel Yeast, Inc.) as a control.

The quality guarantee period detection method comprises the following steps: placing the sample in room temperature environment, periodically detecting microorganism content (total bacterial colony, mould, Escherichia coli) until the microorganism content reaches 10⁶The CFU/g level is considered as sample deterioration. The time from the start of the experiment to the deterioration of the sample was the shelf life of the sample. The results are detailed in Table 5.

TABLE 5

Fermentation strain for coarse cereal steamed bread	Quality guarantee period/day of coarse cereal steamed bread
		Pediococcus acidilactici CGMCC No.21160	8 days
Commercial lactic acid bacteria	5 days

Example 5

This example illustrates the sensory quality of the product when the fermented cereal noodle is prepared using pediococcus acidilactici CGMCC No. 21160.

The fermented coarse cereal powder adopted in the embodiment is coarse cereal powder doped with pediococcus acidilactici CGMCC No.21160 solid fermentation microbial inoculum, wherein the content of the pediococcus acidilactici is 10⁵-10⁶CFU/g. The preparation method of the coarse cereal powder comprises the following steps: stacking the washed coarse cereals (respectively corn, barley and red bean) to make cortex absorb water, soaking for 4-6h, pulverizing in a pulverizer, and sieving with 80 mesh sieve.

The preparation method comprises the following steps: mixing fermented coarse cereal powder and wheat flour according to the weight ratio of 35: 65, and mixing with water in a weight ratio of 2: 1, and then slowly stirring (about 30rpm) for 2-8 minutes, and then quickly stirring (about 60rpm) for 1-15 minutes to form uniform dough. Rolling the flour wadding into smooth flour belt, and cutting into square noodles with thickness of 1 + -0.5 mm and width of 2 + -1 mm.

Barley noodles were prepared as a control using the same method using a commercial lactic acid bacterium (available from Angel Yeast Co., Ltd.).

Inviting food evaluators to perform sensory evaluation on the fermented coarse cereal noodles according to the standards in table 6. The average scores of each assessor were taken as the assessment results, which are detailed in table 7.

TABLE 6

TABLE 7

Species of	Flavor (I) and flavor (II)	Viscosity of	Hardness of hardness	Elasticity	Degree of smoothness	Total score	Flavor description
								Control	2.3	8.2	8.2	8.7	8.8	36.3	Coarse cereals with strong flavor
Corn noodles	8.2	8.2	8.5	8.3	8.7	41.9	Has light corn and wheat fragrance
								Barley noodles	8.9	8.6	8.7	8.8	9	44	Has light malt fragrance
Red bean noodles	8.5	8.2	8.2	8.2	8.5	41.6	Has light fragrance of semen Phaseoli and fructus Hordei Germinatus

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

SEQUENCE LISTING

<110> Zhongliang Nutrition and health research institute Co., Ltd

COFCO Ltd.

<120> pediococcus acidilactici, fermentation inoculant and application thereof, and preparation method of coarse cereal fermented food

<130> I70017COF

<160> 3

<170> PatentIn version 3.5

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gaacaggatt agataccctg ttagtaccct gctgtcaacg ataagagtga ttactaagtg 780

ttggagggtt tccgcccttc agtgctgcag ctaacgcatt aagttatccg cctggggagt 840

acgaccgcaa ggttgaaact caaagaattg acgggggccg cacaagcgtg gagcatgtgg 900

ttaattcgaa gtacgcgaag aacttaccag gtcttgacat ctttgccaac ctaagagatt 960

aggcgttccc tttcggggac agaatgacag gtggtgcatg gttgtcgtca gctcgtgtcg 1020

tgagatgttg ggttaagtcc cgcaacgagc gcaaccctta ttactagttg ccagcattca 1080

gttgggcact ctagtgagac tgccggtgac aaaccggagg aaggtgggga cgacgtcaaa 1140

tcatcatgcc ccttatgacc tgggctacac acgtgctaca atggatggta caacgagttg 1200

cgaaaccgcg aggtttagct aatctcttaa aaccattctc agttcggact gtaggctgca 1260

actcgcctac acgaagtcgg aatcgctagt aatcgcggat cagcatgccg cggtgaatac 1320

gttcccgggc cttgtacaca ccgcc 1345

Claims

1. A Pediococcus acidilactici strain is characterized in that the preservation number of the Pediococcus acidilactici strain is CGMCC No. 21160.

2. A fermentation inoculum comprising the Pediococcus acidilactici of claim 1.

3. According to claim2, wherein the content of pediococcus acidilactici in the fermentation inoculum is 10 in terms of viable count¹⁰CFU/g is above;

4. The fermentation inoculant according to claim 2 or 3, wherein the fermentation inoculant further comprises an auxiliary material;

preferably, the excipient is selected from a lyoprotectant and/or a stabilizer;

more preferably, the lyoprotectant is selected from at least one of skim milk powder, maltodextrin, trehalose, dextran, and glycerol;

5. Use of pediococcus acidilactici according to claim 1 or the fermentation starter according to any one of claims 2 to 4 for preparing a coarse cereal fermented food.

6. A preparation method of a coarse cereal fermented food is characterized by comprising the step of mixing a coarse cereal raw material and pediococcus acidilactici according to claim 1 or a zymophyte agent according to any one of claims 2 to 4 for fermentation.

7. The method according to claim 6, wherein the coarse cereals in the coarse cereal raw material are selected from at least one of red beans, mung beans, barley, sorghum, corn, millet, oat and coix seeds;

and/or the coarse cereal fermented food is selected from at least one of coarse cereal noodles, coarse cereal steamed bread and coarse cereal bread.

8. The method according to claim 6 or 7, wherein the coarse cereal raw material is flour containing coarse cereals, wherein the content of the coarse cereals is more than 10 wt%;

9. The method according to claim 6, wherein the amount of Pediococcus acidilactici or the fermentation inoculant is such that the initial content of Pediococcus acidilactici in the fermentation system is 10⁵-10⁶CFU/mL；

10. The coarse cereal fermented food prepared according to the method of any one of claims 6 to 9.