阅读说明：本技术 一种多菌种复合糙米固态发酵菌剂、制备方法及其应用 (Multi-strain composite brown rice solid-state fermentation microbial inoculum, and preparation method and application thereof ) 是由 谭斌 张笃芹 叶彦均 乔聪聪 于 2021-06-28 设计创作，主要内容包括：本发明公开了一种多菌种复合糙米固态发酵菌剂、制备方法及其应用。所述多菌种复合糙米固态发酵菌剂包括乳酸菌、霉菌、酵母菌和脉孢菌,且乳酸菌、霉菌、酵母菌和脉孢菌的质量比为2～8：0～4：0.1～8：0.1～4。本发明还将上述菌剂用于制备固态发酵含糙米的食品中,可溶性膳食纤维含量显著提高,较未固态发酵糙米提高了138％,多酚类物质含量提高了86％以上,维生素B-(2)和E的含量分别提高了30％和91％,抗氧化活性增大至未发酵糙米的3.8倍以上,同时使糙米颗粒外观更加白润,改善了糙米色泽灰暗的问题,口感更加柔软、粘糯,并且通过不同菌种的代谢过程产生了一系列小分子的风味物质,赋予糙米产品独特的风味特性,味道更加芳香浓郁。(The invention discloses a multi-strain composite brown rice solid-state fermentation microbial inoculum, a preparation method and application thereof. The multi-strain composite brown rice solid fermentation microbial inoculum comprises lactic acid bacteria, mould, saccharomycetes and neurospora, and the mass ratio of the lactic acid bacteria to the mould to the saccharomycetes to the neurospora is 2-8: 0-4: 0.1-8: 0.1 to 4. The microbial inoculum is also used for preparing food containing brown rice through solid state fermentation, the content of soluble dietary fiber is obviously improved, compared with the brown rice which is not subjected to solid state fermentation, the content of the soluble dietary fiber is improved by 138 percent, the content of polyphenol substances is improved by over 86 percent, and vitamin B is added 2 The content of E and E are respectively increased by 30 percent and 91 percent, the antioxidant activity is increased to more than 3.8 times of that of the unfermented brown rice, simultaneously, the brown rice particles are whitened, the problem of dull brown rice color is solved, the taste is softer and sticky, a series of micromolecule flavor substances are generated through the metabolic processes of different strains, the brown rice product is endowed with unique flavor characteristics, and the taste is more aromatic and full-bodied.)

1. The multi-strain composite brown rice solid fermentation microbial inoculum is characterized by comprising lactic acid bacteria, mould, saccharomycetes and neurospora, wherein the mass ratio of the lactic acid bacteria to the mould to the saccharomycetes to the neurospora is 2-8: 0-4: 0.1-8: 0.1 to 4.

2. The multi-strain composite brown rice solid fermentation microbial inoculum according to claim 1, wherein the mass ratio of lactic acid bacteria, mould, yeast and neurospora is 4-8: 2-4: 4-8: 2 to 4.

3. The multi-strain composite brown rice solid fermentation microbial inoculum according to claim 1, wherein the number of viable lactic acid bacteria, mold, yeast and Neurospora is not less than 1 x 10¹⁰cfu/g。

4. The multi-strain composite brown rice solid fermentation inoculant according to claim 1, wherein the lactic acid bacteria comprise lactobacillus plantarum, the mold comprises aspergillus oryzae or rhizopus oryzae, the yeast comprises saccharomyces cerevisiae, and the neurospora comprises neurospora eutropha.

5. The preparation method of the multi-strain composite brown rice solid fermentation inoculant according to any one of claims 1 to 4, which is characterized by comprising the following steps:

firstly, activating required strains to prepare bacterial sludge, then mixing the bacterial sludge according to a formula proportion to prepare composite bacterial sludge, and finally adding sterile water to prepare the multi-strain composite brown rice solid fermentation microbial inoculum.

6. The preparation method according to claim 5, wherein the sterile water and the composite bacterial sludge are prepared in a proportion that the total mass of the composite bacterial sludge added in each 50mL of sterile water is 0.2-0.8 g.

7. An application of a multi-strain composite brown rice solid fermentation microbial inoculum in the preparation of food containing brown rice through solid fermentation is characterized in that the multi-strain composite brown rice solid fermentation microbial inoculum of any one of claims 1 to 6 is mixed with grain raw materials for solid fermentation to obtain solid fermentation grains, and then the solid fermentation grains are prepared into the food containing brown rice through solid fermentation; wherein, in the grain raw material, the mass content of the brown rice is 50-100%; preferably, in the cereal raw material, the mass content of the brown rice is 80-100%.

8. The application of claim 7, wherein the feed-liquid ratio of the cereal raw material to the multi-strain composite brown rice solid fermentation inoculant is 1: 0.2 to 0.7 (w/v); preferably, the material-liquid ratio of the cereal raw material to the multi-strain composite brown rice solid fermentation inoculant is 1: 0.2 to 0.4 (w/v).

9. The application of claim 7, wherein the solid state fermentation temperature is 25-38 ℃ and the fermentation time is 8-48 h; preferably, the fermentation temperature is 27-35 ℃, and the fermentation time is 20-36 h.

10. The use according to claim 7, wherein the brown rice comprises one or more of japonica rice, indica rice and germinated brown rice; the cereal raw materials also comprise one or more of whole wheat, corn, oat, sorghum, highland barley, millet, quinoa, buckwheat, pearl barley, mung bean, red bean, black bean, cowpea, flower bean and soybean.

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to a multi-strain composite brown rice solid state fermentation starter, a preparation method and application thereof.

Background

Rice contains various nutrients including carbohydrates, proteins, lipids, vitamins and dietary fibers. The polished rice is processed by rice shelling, grinding, polishing and other processes, and mainly consists of endosperm parts of rice; the brown rice is directly processed after rice husking and consists of 1-2% of pericarp, 4-6% of aleurone layer and seed coat, 2-3% of embryo bud and 89-94% of starchy endosperm, so that the brown rice contains more nutrient components and has higher nutritive value compared with polished rice. Along with the gradual deepening of people's cognition on the nutritional value of the brown rice, the development and utilization of the brown rice whole grain food are more and more emphasized. However, the rice bran layer of the brown rice is rich in wax and fiber, so that the processing not only prevents the internal tissues of the brown rice from absorbing water and swelling, but also ensures that the brown rice is not easy to cook, has rough mouthfeel and poor taste quality, and limits the eating and development of the brown rice.

Solid state fermentation is a fermentation process carried out on an inert carrier or a water-insoluble substrate in the absence or near absence of free water. Since solid state fermentation is performed under conditions of very little free water, which is closer to the natural environment adapted by microorganisms, solid state fermentation has higher fermentation productivity, lower catabolic repression, lower water activity, lower aseptic operation requirements, and the like, compared to liquid state fermentation.

The solid-state fermentation of the brown rice can destroy the integrity of the structure of the brown rice cortex and the compactness of internal tissue connection by using enzymes generated in the fermentation process of microorganisms, soften the brown rice cortex, enhance the water absorption of the brown rice cortex and shorten the cooking time of the brown rice; secondly, the enzymolysis in the strain metabolism process can optimize the nutrient substance proportion in the brown rice and improve the content of functional active substances, thereby enhancing the nutritive value of the brown rice; finally, a series of micromolecule flavor substances are generated in the strain metabolism process, and the unique texture and flavor characteristics of the brown rice are endowed. In conclusion, the solid fermentation can improve the processing, eating and functional quality of the brown rice, but the existing brown rice solid fermentation related researches mostly adopt a single strain or a small amount of strains, and the improvement effect on the brown rice quality is limited.

Therefore, it is important to provide a multi-strain solid fermentation microbial inoculum to improve the quality of brown rice-containing food.

Disclosure of Invention

The first purpose of the invention is to provide a multi-strain composite brown rice solid fermentation microbial inoculum.

The second purpose of the invention is to provide a preparation method of the multi-strain composite brown rice solid-state fermentation microbial inoculum, which has the advantages of simple and convenient operation, less used equipment and strong industrial application.

The third purpose of the invention is to provide the application of the multi-strain composite brown rice solid fermentation microbial inoculum in solid fermentation of brown rice-containing food, the multi-strain microbial inoculum is used in solid fermentation of grain raw materials, the problems that brown rice is not easy to cook and has rough taste caused by high content of insoluble dietary fibers in brown rice cortex are solved, the content of free polyphenol substances can be increased, the in-vitro antioxidant activity of brown rice is enhanced, the problems that brown rice is dark in color, bad in taste and quality and the like are greatly improved, and the improvement of brown rice quality is obvious.

In order to achieve the first purpose, the technical scheme adopted by the invention is as follows:

the invention provides a multi-strain composite brown rice solid fermentation microbial inoculum which comprises lactic acid bacteria, mould, saccharomycetes and neurospora, wherein the mass ratio of the lactic acid bacteria to the mould to the saccharomycetes to the neurospora is (2-8): 0-4: 0.1-8: 0.1 to 4.

Further, the mass ratio of the lactic acid bacteria to the mould to the yeast to the neurospora is 4-8: 2-4: 4-8: 2 to 4.

The lactic acid bacteria, the mould, the microzyme and the Neurospora are freeze-dried.

Further, the number of viable bacteria of lactic acid bacteria, mold, yeast and Neurospora is not less than 1 × 10¹⁰cfu/g。

Further, the lactic acid bacteria include, but are not limited to, lactobacillus plantarum, the mold includes, but is not limited to, aspergillus oryzae or rhizopus oryzae, the yeast includes, but is not limited to, saccharomyces cerevisiae, and the neurospora includes, but is not limited to, neurospora eutropha.

The lactic acid bacteria, the mould, the microzyme and the Neurospora are all from single commercially-available live bacteria preparations of various strains, or microbial agents prepared by strictly sterile culture of any known strains which are identified as corresponding strains microbiologically are used.

In order to achieve the second purpose, the technical scheme adopted by the invention is as follows:

the invention provides a preparation method for preparing the multi-strain composite brown rice solid-state fermentation microbial inoculum, which comprises the following steps:

firstly, activating required strains to prepare bacterial sludge, then mixing the bacterial sludge according to a formula proportion to prepare composite bacterial sludge, and finally adding sterile water to prepare the multi-strain composite brown rice solid fermentation microbial inoculum.

Further, the sterile water and the composite bacterial sludge are prepared according to the proportion that the total mass of the composite bacterial sludge added in each 50mL of sterile water is 0.2-0.8 g.

According to the specific embodiment of the invention, before the brown rice product is used, the saccharomyces cerevisiae, the lactobacillus plantarum, the bacillus or the mould used in the invention can be activated according to the method known in the field to obtain the strain with vigorous activity, so as to improve the effect of modifying the brown rice product. For example, the strain activation can be performed as follows:

activation of lactic acid bacteria (e.g., Lactobacillus plantarum, aerobic): inoculating lactobacillus plantarum into an MRS broth culture medium without agar, activating for 2 generations, centrifuging for 3-5 min at 3000-4000 r/min, and washing with 0.8% sterile normal saline to respectively obtain precipitated white lactobacillus plantarum bacterial sludge; the preparation method of the agar-free MRS broth culture medium comprises the following steps: 10g of peptone, 5g of beef powder, 20g of glucose, 4g of yeast powder, 5g of sodium acetate, 2g of dipotassium hydrogen phosphate, 0.2g of magnesium sulfate, 2g of triammonium citrate, 0.05g of manganese sulfate and 1mL of Tween 80, mixing, adding 1000mL of distilled water, heating, boiling, dissolving, filling into a triangular flask, sealing, and sterilizing at 121 ℃ for 20min under high pressure.

Activation of mold (e.g., Aspergillus oryzae, Rhizopus oryzae, both aerobic): respectively inoculating aspergillus oryzae and rhizopus oryzae into a Chachi liquid culture medium and a potato glucose liquid culture medium, activating for 2 generations, centrifuging for 3-5 min at 3000-4000 r/min, washing with 0.8% sterile normal saline to respectively obtain precipitated aspergillus oryzae and rhizopus oryzae bacterial sludge; the preparation method of the Chachi liquid culture medium comprises the following steps: mixing 30g of sucrose, 3g of sodium nitrate, 0.5g of magnesium sulfate heptahydrate, 0.5g of potassium chloride, 0.01g of ferric sulfate tetrahydrate and 1g of potassium hydrogen phosphate, adding the mixture into 1000mL of distilled water, heating to boil and dissolve the mixture, putting the mixture into a triangular flask, sealing the triangular flask, and carrying out autoclaving at 121 ℃ for 20 min; the preparation method of the potato glucose liquid medium comprises the following steps: 1.0L potato extractive solution (peeled potato 200g, cut into small pieces, adding water 1.0L, boiling for 30min, filtering to remove potato pieces, adding filtrate to 1.0L) and glucose 20g, mixing, adding into 1000mL distilled water, heating to boil and dissolve, placing into triangular flask and sealing, and autoclaving at 121 deg.C for 20 min.

Activation of yeasts (e.g.Saccharomyces cerevisiae, aerobic): inoculating saccharomyces cerevisiae into a yeast leaching peptone glucose broth culture medium without agar, activating for 2 generations, centrifuging for 3-5 min at 3000-4000 r/min, and washing with 0.8% sterile normal saline to obtain precipitated white saccharomyces cerevisiae bacterial sludge. The preparation method of the agar-free yeast leaching peptone glucose broth culture medium comprises the following steps: mixing peptone 10g, yeast extract powder 5g and glucose 20g, adding into 1000mL distilled water, heating to boil and dissolve, placing into a triangular flask, sealing, and autoclaving at 121 deg.C for 20 min.

Activation of Neurospora (e.g., Neurospora eutropha, aerobic): respectively performing activation culture on the freeze-dried powder of the good vein-eating spore fungi in a PDA culture medium without agar, performing oscillation activation culture for 18h in a constant temperature incubator at the constant temperature of 28 ℃, then centrifuging for 5min at 3000r/min, and washing for 3 times by using 0.8% sterile physiological saline to respectively obtain bacterial sludge of the good vein-eating spore fungi. The preparation method of the agar-free PDA culture medium comprises the following steps: cutting 200g of potato into small pieces, adding water, boiling for 20-30 min until the potato pieces can be punctured by a glass rod, filtering with gauze, heating the obtained filtrate, adding 20g of glucose, stirring uniformly, filling into a triangular flask, sealing, and sterilizing at 121 ℃ for 20 min.

The agar-free MRS broth culture medium, the agar-free yeast extract peptone dextrose broth culture medium, the Chachi liquid culture medium, the potato dextrose liquid culture medium and the agar-free PDA culture medium used in the present invention can be purchased externally or prepared by the above-mentioned methods.

In order to achieve the third purpose, the technical scheme adopted by the invention is as follows:

the invention provides an application of the microbial inoculum in solid state fermentation of brown rice-containing food, wherein the microbial inoculum is mixed with grain raw materials for solid state fermentation to obtain solid state fermented grains, and then the solid state fermented grains are prepared into the solid state fermented brown rice-containing food; wherein, in the grain raw material, the mass content of the brown rice is 50-100%.

Further, in the grain raw material, the mass content of the brown rice is 80-100%.

According to the embodiment of the invention, the pretreatment operation of the cereal raw material (the mass ratio of the brown rice is more than 50%) is as follows: removing impurities in the grain raw materials through screening, soaking for 2-3 h in drinking water, drying at 40-50 ℃ until the water content is 10% -20%, and then sterilizing for 20min at 121 ℃.

Further, the feed-liquid ratio of the cereal raw material to the multi-strain composite brown rice solid fermentation microbial inoculum is 1: 0.2 to 0.7 (w/v); preferably, the feed-liquid ratio of the cereal raw material to the multi-strain composite brown rice solid fermentation microbial inoculum is 1: 0.2 to 0.4 (w/v).

Further, the fermentation temperature of the solid state fermentation is 25-38 ℃, and the fermentation time is 8-48 h; preferably, the fermentation temperature is 27-35 ℃, and the fermentation time is 20-36 h.

Further, the brown rice includes, but is not limited to, one or more of japonica rice, indica rice and germinated brown rice.

Further, the cereal raw material also comprises one or more of whole wheat, corn, oat, sorghum, highland barley, millet, quinoa, buckwheat, coix seed, mung bean, red bean, black bean, cowpea, flower bean and soybean.

The technical scheme provided by the invention aims at the application of solid-state fermentation to the food containing the brown rice, the microbial inoculum provided by the invention not only has a better improvement effect on the brown rice, but also has a certain improvement effect on cereal raw materials containing wholewheat, corn, oat, sorghum, highland barley, millet, quinoa, buckwheat, coix seed and the like, and the higher the mass content of the brown rice is, the more remarkable the comprehensive improvement effect is.

The food containing brown rice by solid state fermentation in the present invention includes, but is not limited to, brown rice coarse cereal rice, brown rice porridge, brown rice coarse cereal porridge, and brown rice cake.

Cereal materials in the present invention include, but are not limited to, whole grain, dehulled grain, cut grain, and crushed grain.

According to the invention, saccharomyces cerevisiae, lactobacillus plantarum and neurospora parvum or mould are adopted to carry out compound solid-state fermentation biological modification on the grain raw materials (the mass ratio of the brown rice is more than 50%), and compared with untreated brown rice, the solid-state fermentation grain raw materials can damage the integrity of the structure of the cortex of the brown rice and the compactness of internal tissue connection by using enzymes generated in the fermentation process of microorganisms, soften the cortex of the brown rice, enhance the water absorption of the brown rice and shorten the cooking time of the brown rice. Furthermore, the content and the effectiveness of bioactive substances such as soluble dietary fibers, phenolic substances and the like in the brown rice are obviously improved, and the in-vitro antioxidant activity of the brown rice is enhanced, so that the brown rice product has higher nutritional value. The neurospora prolifera thalli contains rich protein, B vitamins and the like, and is a commonly used beneficial strain in the fermentation industry, in addition, cellulase produced by metabolism of the neurospora prolifera and mould can effectively decompose insoluble dietary fibers in the brown rice, generate more carbohydrates which can be used by growth of saccharomycetes and lactic acid bacteria, enhance the adsorption of the brown rice on water, and are beneficial to shortening the processing time of the brown rice. A series of micromolecular flavor substances are generated in the multi-strain metabolic process, unique texture and flavor characteristics of the brown rice are endowed, the problems of dull brown rice color, poor taste and quality and the like are greatly improved, and the edible degree of the brown rice product is improved.

The invention has the beneficial effects that:

the lactobacillus, mould, microzyme and neurospora multi-strain composite brown rice solid fermentation microbial inoculum provided by the invention is suitable for solid fermentation of grain raw materials (the mass ratio of brown rice is more than 50%), and has a wide application range. The multi-strain composite brown rice solid fermentation microbial inoculum provided by the invention can be used for producing brown rice-containing foods such as brown rice coarse cereal rice, brown rice porridge, brown rice cake and the like, the content of soluble dietary fiber is obviously improved, compared with the non-solid fermentation brown rice, the content of polyphenol is improved by 138%, the content of vitamin B is improved by more than 86%, and the like₂The content of E and E are respectively improved by 30 percent and 91 percent, and the antioxidant activity is increased to more than 3.8 times of that of the unfermented brown rice; in addition, the brown rice produced by the multi-strain composite brown rice solid fermentation microbial inoculum is white and moist in color, the problem of dull brown rice color is solved, the brown rice product is softer and sticky in taste, a series of micromolecular flavor substances are generated through the metabolic processes of different strains, the brown rice product is endowed with unique flavor characteristics, and the taste is more aromatic and full-bodied.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. These examples are only illustrative of the present invention and are not intended to limit the scope of the present invention. The methods described in the following examples are conventional methods unless otherwise specified; the materials are commercially available, unless otherwise specified.

The strains used in the invention are all commercially available strains and are derived from China Industrial microbial culture Collection management center (CICC), wherein the number of the saccharomyces cerevisiae strain is CICC 1223, the number of the lactobacillus plantarum strain is CICC 22696, the number of the aspergillus oryzae strain is CICC 41737, the number of the rhizopus oryzae strain is CICC 40282, the number of the neurospora facilis strain is CICC 40204, the number of the pediococcus pentosaceus is CICC 22145, and the number of the pichia pastoris is CICC 1688.

Example 1

The embodiment provides coarse cereal rice made of brown rice, oat, coix seed, mung bean, red bean and flower bean, which are mixed in a mass ratio of 60%, 20%, 5% and 5%;

the multi-strain composite brown rice solid fermentation microbial inoculum comprises lactobacillus plantarum, aspergillus oryzae, saccharomyces cerevisiae and neurospora cerevisia, and the number of viable bacteria of each strain is not less than 1 multiplied by 10¹⁰cfu/g；

The preparation method of the brown rice and coarse cereal rice comprises the following steps:

(1) screening brown rice, oat, coix seed, mung bean, red bean and flower bean to remove other impurities in the materials, uniformly mixing to obtain mixed brown rice, soaking in drinking water for 3h, drying at 40-50 ℃ until the water content is 15%, and sterilizing at 121 ℃ for 20min for later use.

(2) Activating lactobacillus plantarum, aspergillus oryzae, saccharomyces cerevisiae and neurospora facilis according to the method, mixing according to the mass ratio of 3:1:6:2, preparing composite bacterial sludge, adding 0.4g of the total mass of the composite bacterial sludge into every 50mL of sterile water, and preparing the multi-strain composite brown rice solid state fermentation microbial inoculum.

(3) Adding the solid fermentation microbial inoculum into a fermentation bag according to a feed liquid ratio of 1:0.5(w/v), shaking to fully infiltrate the mixed brown rice, and standing and culturing in an incubator at 28 deg.C for 30h to obtain solid fermentation mixed brown rice.

(4) And (3) steaming the solid-state fermented mixed brown rice and drinking water in an electric cooker for 30min according to the mass ratio of 1:2 to obtain the solid-state fermented brown rice and coarse cereal rice.

Example 2

This example provides a brown rice-coarse cereal rice, which is prepared by the same method as in example 1, and is different from example 1 only in that: the multi-strain composite brown rice solid fermentation microbial inoculum is prepared by mixing lactobacillus plantarum, saccharomyces cerevisiae and neurospora facilis according to the mass ratio of 2:7: 2.

Example 3

The embodiment provides a brown rice cake, the microbial inoculum is the same as that in embodiment 1, and the brown rice cake is only made of brown rice;

the preparation method of the brown rice cake comprises the following steps:

(1) selecting high-quality brown rice, screening to remove impurities, soaking in drinking water for 3h, drying at 40-50 ℃ until the water content is 15%, and sterilizing at 121 ℃ for 20min for later use.

(2) Activating lactobacillus plantarum, aspergillus oryzae, saccharomyces cerevisiae and neurospora facilis according to the method, mixing according to the mass ratio of 3:1:6:2, preparing composite bacterial sludge, adding 0.4g of the total mass of the composite bacterial sludge into every 50mL of sterile water, and preparing the multi-strain composite brown rice solid state fermentation microbial inoculum.

(3) Adding the solid fermentation microbial inoculum into a fermentation bag according to a feed-liquid ratio of 1:0.3(w/v), shaking to fully infiltrate the mixed brown rice, and standing and culturing in an incubator at 28 deg.C for 30h to obtain the solid fermentation brown rice.

(4) Steaming the solid-state fermented brown rice and drinking water in an electric cooker for 30min according to the mass ratio of 1:1.5, and performing compression molding on the steamed brown rice by using a rice cake molding die to finally obtain the brown rice cake.

Comparative example 1

The comparative example provides coarse cereal rice with brown rice, which is prepared by the method similar to that of example 1, and is only different from the method of example 1 in that: the multi-strain composite brown rice solid fermentation microbial inoculum is prepared by mixing lactobacillus plantarum, aspergillus oryzae and vein-eating spore bacillus according to the mass ratio of 2:1: 1.

Comparative example 2

The comparative example provides coarse cereal rice with brown rice, which is prepared by the method similar to that of example 1, and is only different from the method of example 1 in that: the multi-strain composite brown rice solid fermentation microbial inoculum is prepared by mixing lactobacillus plantarum and saccharomyces cerevisiae according to the mass ratio of 3: 1.

Comparative example 3

The comparative example provides coarse cereal rice with brown rice, which is prepared by the method similar to that of example 1, and is only different from the method of example 1 in that: the brown rice solid fermentation microbial inoculum only consists of single-bacterium lactobacillus plantarum.

Comparative example 4

The comparative example provides coarse cereal rice with brown rice, which is prepared by the method similar to that of example 1, and is only different from the method of example 1 in that: the lactobacillus plantarum in the multi-strain composite brown rice solid fermentation microbial inoculum is replaced by pediococcus pentosaceus.

Comparative example 5

The comparative example provides a brown rice cake, which is prepared by the same method as the example 3, and is only different from the example 3 in that: the multi-strain composite brown rice solid fermentation microbial inoculum consists of aspergillus oryzae and saccharomyces cerevisiae according to the mass ratio of 1: 3.

Comparative example 6

The comparative example provides a brown rice cake, which is prepared by the same method as the example 3, and is only different from the example 3 in that: the multi-strain composite brown rice solid fermentation microbial inoculum consists of aspergillus oryzae and rhizopus oryzae according to the mass ratio of 2: 3.

Comparative example 7

The comparative example provides a brown rice cake, which is prepared by the same method as the example 3, and is only different from the example 3 in that: the multi-strain composite brown rice solid fermentation microbial inoculum consists of single-strain Neurospora eutropha.

Comparative example 8

The comparative example provides a brown rice cake, which is prepared by the same method as the example 3, and is only different from the example 3 in that: in the multi-strain composite brown rice solid fermentation microbial inoculum, lactobacillus plantarum is replaced by pediococcus pentosaceus, and saccharomyces cerevisiae is replaced by pichia pastoris.

Test example 1

The test method comprises the following steps:

(1) determination of soluble dietary fiber content

The soluble dietary fiber content was determined by the method of AOAC (2000).

(2) Folin-Ciocalteu method for determining content of polyphenol substances

Accurately weighing 2.00g of brown rice sampleAdding into 50mL plastic centrifugal tube, adding 40mL methanol, ultrasonic extracting (40 deg.C, 100% power, ultrasonic 30min), centrifuging (3500r/min for 10min), collecting supernatant, repeating the operation for 1 time, mixing supernatants, rotary evaporating at 40 deg.C, and diluting with methanol to 2 mL. Mixing 250 μ L sample diluent with 500 μ L distilled water and 250 μ L Fulinfol reagent, reacting for 6min, adding 2.5mL 7g/100mL Na₂CO₃The solution was reacted with 2mL of distilled water at room temperature in the dark for 90min, and the absorbance was measured at 765 nm. A standard curve is established by taking gallic acid as a standard sample, and the polyphenol content of the sample is expressed by the milligrams of gallic acid contained in 100g of dry base (abbreviated as mg/100 g).

(3) Vitamin B₂Determination of the content

For natural fluorescent vitamin B₂The sample extract was filtered and then directly filtered using a 0.45 μm membrane filter for use. The mobile phase was methanol and 0.05M sodium acetate (30:70, v/v) and was separated on a column C18 from Zorbax Eclipse. Gradient elution was performed at a flow rate of 1mL/min, the column temperature was set at 40 ℃ and the injection amount was 20. mu.L. Detection of vitamin B Using a fluorescence Detector at an excitation wavelength of 422nm and an emission wavelength of 522nm₂。

(4) Determination of vitamin E content

Vitamin E extraction was performed according to the method described in SMAHC (1990). The sample was hydrolyzed in potassium hydroxide-ethanol solution with pyrogallol as an antioxidant. The hydrolysate was then extracted with petroleum ether, the organic phase was washed off with water and the hydrolysate was dehydrated with anhydrous sodium sulphate. Dissolving the concentrated extract in n-hexane. A certain amount of n-hexane dissolved solution was taken for HPLC analysis. As a mobile phase, n-hexane containing 0.75% (v/v) isopropyl alcohol was used, and the flow rate was 1 mL/min. Vitamin E congener mixtures (α, β, γ, δ -tocopherol) were purchased from Eizai, tokyo, as standard.

(5) Determination of color and luster

Color was measured using an integrating sphere spectrophotometer model U.S. X-Rite SP 60.

(6) Measurement of hardness and viscosity

The brown rice cake was uniformly pressed into a cylindrical shape having a diameter of 4.5cm and a height of 4.0cm, and the hardness and viscosity thereof were analyzed by a texture analyzer.

(7) Determination of the content of flavor substances

The 1g sample was placed in a 2mL sample vial and the compounds were separated and analyzed by gas chromatography-mass spectrometer (shimadzu GC-MS QP2010 plus).

The experimental conditions are as follows: solid phase microextraction conditions: a65-micron PDMS/DVB extraction head is adopted, a sample is placed at 50 ℃ for balancing for 20min, then the extraction head is inserted into a headspace bottle for extraction for 40min, and finally the extraction head is pulled out and placed in a sample inlet at 250 ℃ for desorption for 2 min. Gas chromatography conditions: the chromatographic column model DB-WAX (30m × 0.25mm × 0.25 μm), the initial temperature of the column incubator of 40 deg.C, the injection inlet temperature of 250 deg.C, no-flow injection, the carrier gas flow rate of 1mL/min, the temperature raising program of the column incubator of 40 deg.C for 3min, 5 deg.C/min for 120 deg.C, 10 deg.C/min for 230 deg.C for 5 min. Mass spectrum conditions: the ion source temperature is 200 ℃, the transmission line temperature is 250 ℃, signals are collected in a full scanning (Scan) mode, and the scanning range is 35-500 m/z.

And (4) comparing the results:

table 1 shows the soluble dietary fibres, polyphenols, vitamin B between the different controls, examples and comparative examples₂Comparison of vitamin E and antioxidant activity. The brown rice, coarse cereal rice and brown rice cake prepared by solid fermentation of Lactobacillus plantarum, Saccharomyces cerevisiae, Neurospora sitophila and/or Aspergillus oryzae in soluble dietary fiber, polyphenol substances, and vitamin B₂And E, the antioxidant activity is obviously superior to that of the data without solid state fermentation, and the test data obtained by adjusting the proportion of each strain or changing the formula of the strain is also lower than that of the technical scheme provided by the invention.

The specific strain combination and the strain proportion provided by the invention can obtain higher soluble dietary fiber, more polyphenols and vitamin B₂And E is more, and the anti-oxidation activity is stronger, wherein the soluble dietary fiber of the solid-state fermented coarse cereal rice is more than 2.38 times of that of the non-solid-state fermented coarse cereal rice, the polyphenol substances are more than 1.86 times of that of the non-solid-state fermented coarse cereal rice,vitamin B₂The vitamin E is improved by more than 30 percent, the vitamin E is improved by more than 91 percent, and the antioxidant activity is 3.8 times of that of the original vitamin E; the soluble dietary fiber of the solid-state fermented brown rice cake is more than 2.81 times of that of the non-solid-state fermented brown rice cake, the polyphenols are more than 2.86 times, and vitamin B₂The content of vitamin E is improved by more than 49%, the content of vitamin E is improved by more than 110%, the anti-oxidation activity is 4 times of the original activity, and the introduction of the multi-strain composite brown rice solid fermentation microbial inoculum has a good effect on solid fermentation brown rice coarse cereal rice and brown rice cakes, because the microbial inoculum effectively destroys the integrity of brown rice husks, the ratio of nutrient substances in brown rice is optimized, the content of functional active substances is improved, the nutritive value of brown rice is enhanced, and as can be seen from table 1, all test data are increased after the addition of aspergillus oryzae. In addition, although the comparative example only mechanically adjusts the strain types or the proportion in the microbial inoculum, the effect is obviously lower than that of the microbial inoculum formula provided by the invention, and the selected microbial inoculum formula is the optimal formula combination obtained through a large number of experiments.

TABLE 1 soluble dietary fiber, polyphenols, vitamin B₂Comparison of vitamin E and antioxidant Activity

Note: the control group 1 is non-solid-state-fermented brown rice and coarse cereals rice, and the control group 2 is non-solid-state-fermented brown rice cake.

Table 2 shows the color, hardness and viscosity comparisons between different controls, examples and comparative examples. The brown rice and coarse cereals rice after being subjected to solid state fermentation by lactobacillus, aspergillus oryzae, saccharomyces cerevisiae and neurospora parvum makes the hardness value of a brown rice product obviously smaller than that of the brown rice and coarse cereals rice of a control group 1 and comparative examples 1-4, the brown rice and coarse cereals rice is softer and sticky and has better mouthfeel, and in terms of color, the L value is obviously larger than that of the brown rice and coarse cereals rice of the control group 1 and comparative examples 1-4, so that the problem that the brown rice is dark in color can be effectively improved by introducing the multi-strain composite brown rice solid state fermentation microbial inoculum, and similar conclusion can be obtained by the brown rice cake after solid state fermentation.

TABLE 2 comparison of color, hardness and viscosity

Note: the control group 1 is non-solid-state-fermentation coarse rice and coarse cereal rice, and the control group 2 is non-solid-state-fermentation coarse rice cake; and L, a and b are colorimetric values representing the colors of the object, L represents the brightness, a represents red and green, and b represents yellow and blue.

Table 3 shows the comparison of the flavour content between the different control groups, examples and comparative examples. The contents of alcohol, aldehyde, ester, ketone and other flavor substances in the examples 1 to 3 are obviously improved, namely the alcohol content of the solid-state fermented coarse cereal rice is improved by more than 29%, the aldehyde content is improved by more than 53%, the ester content is improved by more than 344%, and the ketone content is improved by more than 109%, compared with the non-solid-state fermented coarse cereal rice, the alcohol content of the solid-state fermented coarse cereal rice is improved by more than 34%, the aldehyde content is improved by more than 193%, the ester content is improved by more than 230%, and the ketone content is improved by more than 93%.

TABLE 3 comparison of the flavour content

Note: the control group 1 is non-solid-state-fermented brown rice and coarse cereals rice, and the control group 2 is non-solid-state-fermented brown rice cake.

It should be understood that the above-described examples are merely illustrative for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. Not all embodiments are exhaustive. All obvious changes and modifications which are obvious to the technical scheme of the invention are covered by the protection scope of the invention.