Method for improving purity of retrogradation starch containing prolamin through monascus fermentation

Abstract

The invention discloses a method for improving the purity of retrogradation starch containing prolamin through monascus fermentation. And mixing and stirring corn amylose and a prolamin component 3 (a supernatant obtained by refrigerating and precipitating a vital gluten alcohol extract, and a precipitate obtained by freezing and unfreezing) to prepare the low-viscosity prolamin component 3. Protein and starch are mixed and retrograded according to the proportion of 4% of prolamin component 1 (precipitation after refrigeration of vital gluten alcohol extract), 1% of low-viscosity prolamin 3 and 95% of corn amylopectin to obtain prolamin-containing retrograded starch. Mixing alcohol-soluble protein-containing retrogradation starch and coix seeds according to a mass ratio of 7: 3 to obtain a culture medium, and carrying out moist heat sterilization at 110 DEG C for 40 minutes; and inoculating the sterile water containing spores to the culture medium, and culturing and fermenting at a constant temperature of 32 DEG C for 20-33 days. And drying the fermented culture medium in an air dry oven at 60 DEG C until the weight is constant, and crushing. According to the method disclosed by the invention, the purity of the retrogradation starch containing the prolamin is improved from less than 40% to more than 60%.

Description

Technical Field

[0001] The invention relates to a method for improving the purity of retrograded starch containing alcohol-soluble protein by utilizing Monascus fermentation. Background Art

[0002] Monascus is a filamentous fungus that can be used for both medicine and food. It has been used in medicine and food fermentation in China, Japan and other Southeast Asian countries for more than 2,000 years. The production process and medical uses of red yeast rice are recorded in detail in the Compendium of Materia Medica. Monascus fermentation changes the flavor of food while giving it certain functionality. Monascus and its secondary metabolites are widely used in tea, wine, meat, condiments and functional foods as a natural exogenous food additive. Starch, as a carbohydrate, is the main source of energy for human physiological processes. It was previously believed that all starch could be enzymatically digested in the digestive system and then eventually absorbed into the circulation. However, with further research, a unique type of starch that cannot be digested and absorbed by the small intestine was discovered and named resistant starch. Resistant starch is not digested and absorbed in the small intestine, and when it reaches the colon, it is fermented by intestinal microorganisms. In 1992, the Food and Agriculture Organization of the United Nations considered resistant starch to be a general term for starch and starch degradation products that cannot be digested by the small intestine in healthy people. Resistant starch has physiological functions such as preventing, relieving and treating constipation, controlling diabetes, promoting the metabolism of lipids and cholesterol, promoting mineral absorption, and enhancing disease resistance. Retrograded starch containing alcohol-soluble protein is a type of resistant starch. The research team found that wheat alcohol-soluble protein has the effect of promoting the retrogradation of corn amylopectin. The mechanism is that the addition of wheat alcohol-soluble protein components will increase the retrogradation nucleation index of amylopectin, reduce the energy required for retrogradation nucleation of amylopectin, and promote retrogradation. The content of resistant starch in retrograded starch containing alcohol-soluble protein is usually less than 50%, and the purity is low. To achieve a significant laxative effect, according to international standards, a normal person should consume no less than 30g of resistant starch per day, and products with low purity need to consume more than 60g, which is not conducive to its large-scale application in food. In order to improve its purity, the research team used an amylase hydrolysis method, which can increase the purity of the product to more than 60%, but the product obtained by hydrolysis has a bitter taste, which has a great impact on the sensory quality. The reason may be that food-grade amylase decomposes part of the protein while enzymatically hydrolyzing starch, so a green and environmentally friendly technology that can effectively improve the purity of retrograded starch is needed. The Monascus fermentation process can utilize the starch that has not participated in the retrogradation in the retrogradation starch to improve the purity of the retrogradation starch, while secreting functional ingredients such as lovastatin, thereby increasing the purity of the retrogradation starch containing alcohol-soluble proteins and adding a lipid-lowering effect to the product. Summary of the invention

[0003] The invention aims to overcome the shortcomings of the prior art and provides a method for improving the purity of retrograded starch containing alcohol-soluble protein by using Monascus fermentation.

[0004] The present invention is achieved through the following technical scheme: a method for improving the purity of retrograded starch containing alcohol-soluble protein by fermentation with Monascus purpureus, comprising the following steps:

[0005] Corn amylose and alcohol-soluble protein component 3 (supernatant after cold precipitation of gluten alcohol extract, precipitate after freezing and thawing) are mixed in a mass ratio of 1:20 to 1:40, and stirred and mixed for 20 to 40 minutes in a water bath at 30 to 40°C to obtain low-viscosity alcohol-soluble protein component 3. Alcohol-soluble protein component 1 (precipitate after cold storage of gluten alcohol extract) accounts for 4%, low-viscosity alcohol-soluble protein 3 accounts for 1% and corn amylopectin accounts for 95%, and then gelatinized, high-pressured, and cold-stored for 3 to 7 days to obtain alcohol-soluble protein-containing retrograded starch;

[0006] The alcohol-soluble protein-containing retrograded starch and coix seeds were mixed in a mass ratio of 7:3 as a culture medium, and the culture medium was sterilized at a high pressure steam sterilizer at a sterilization temperature of 110°C for a sterilization time of 40 minutes. The purified Monascus slant culture medium was shaken with sterile water on a sterile operating table, and the Monascus spores in the slant culture medium were dispersed in sterile water. The spore-containing sterile water was placed in a spray bottle after autoclaving and sprayed onto the sterilized culture medium, and placed in a 32°C constant temperature incubator for fermentation for 20 to 33 days. The fermented culture medium was dried to constant weight in a forced air drying oven at 60°C and then crushed.

[0007] Compared with the prior art, the present invention has the following beneficial effects:

[0008] The method of the present invention does not use the traditional culture medium with maltose as the carbon source and peptone as the nitrogen source, but only uses the culture medium in which alcohol-soluble protein-containing retrograded starch and coix seeds are mixed to provide the carbon source and nitrogen source. Monascus directly uses the nutrients in alcohol-soluble protein, starch and coix seeds for growth, which not only improves the purity of the retrograded starch in the starch, but also secretes beneficial secondary metabolites such as lovastatin, monascus pigment, and γ-aminobutyric acid. The alcohol-soluble protein-containing retrograded starch fermented by Monascus not only improves the effect of promoting laxative effect, but also combines the blood lipid lowering effect of lovastatin produced by Monascus fermentation, thereby producing a green and safe functional food that has the functions of promoting laxative effect and lowering blood lipid. The purity of the alcohol-soluble protein-containing retrograded starch before and after Monascus fermentation is determined by enzymatic hydrolysis weighing method, and the purity of the alcohol-soluble protein-containing retrograded starch is increased from less than 40% to more than 60%.

[0009] Instruction Manual

[0010] Figure 1 This is a picture of Monascus fermenting in a medium containing alcohol-soluble protein retrograded starch and coix seed for 20 days;

[0011] Figure 2 This is a picture of Monascus fermenting in a coix seed culture medium containing alcohol-soluble protein retrograded starch for 33 days. DETAILED DESCRIPTION

[0012] The present invention is further described in detail below in conjunction with specific embodiments.

[0013] Example 1

[0014] 10g of corn amylose and 200g of alcohol-soluble protein component 3 (supernatant after cold precipitation of gluten alcohol extract, precipitate after freezing and thawing) were mixed, and stirred and mixed for 20min in a 30°C water bath to obtain 234g of low-viscosity alcohol-soluble protein component 3. 40g of alcohol-soluble protein component 1 (precipitate after cold storage of gluten alcohol extract), 10g of low-viscosity alcohol-soluble protein 3 and 950g of corn amylopectin were mixed, gelatinized at 85°C for 30min, then subjected to wet heat and high pressure treatment at 110°C for 20min, and refrigerated at 4°C for 3 days to obtain alcohol-soluble protein-containing retrograded starch, gelatinized, high pressure, and refrigerated for 7d, and then dried and crushed to obtain 585g of alcohol-soluble protein-containing retrograded starch.

[0015] Weigh 30g of coix seed and 70g of alcohol-soluble protein-containing retrograded starch, add 40ml of tap water to coix seed, soak at 35℃ for 3h, stir with alcohol-soluble protein-containing retrograded starch, mix well and transfer to a triangular flask and seal with cotton plug and newspaper; measure 40ml of deionized water in a beaker and seal it with newspaper; at the same time, wrap the medicine spoon, glass rod, culture dish, spray bottle, etc. with newspaper; place the above items in a high-pressure steam sterilizer at 110℃ for 20min. Open the clean bench for ultraviolet sterilization for 30min, and use aseptic operation to pour the cooled deionized water into the Monascus slant culture medium and shake it to disperse the spores in the sterile water. Then put the spore-containing sterile water into the sterilized spray bottle, spray the Monascus spores into the conical flask and mix them evenly by stirring, and place it in a 32℃ constant temperature incubator for constant temperature culture for 20 days. After fermentation, the culture medium was placed in a 65°C oven to dry to constant weight, crushed through a 100-mesh sieve, and the resistant starch content was determined by enzymatic hydrolysis and weighing. The resistant starch content of the alcohol-soluble protein retrograded starch before Monascus fermentation was 39.70%, and the resistant starch content after fermentation was 64.73%. The Monascus is classified and named Monascus purpureus, with the preservation number: CGMCC No.40898. It was deposited in the General Microbiology Center of China National Microbiological Culture Collection Administration on October 16, 2023.

[0016] Example 2

[0017] 10g of corn amylose and 400g of alcohol-soluble protein component 3 (supernatant after cold precipitation of gluten alcohol extract, precipitate after freezing and thawing) were mixed, and stirred and mixed for 40min in a 40°C water bath heating to obtain 472g of low-viscosity alcohol-soluble protein component 3. 40g of alcohol-soluble protein component 1 (precipitate after cold storage of gluten alcohol extract), 10g of low-viscosity alcohol-soluble protein 3 and 950g of corn amylopectin were mixed, gelatinized at 85°C for 30min, then subjected to wet heat and high pressure treatment at 110°C for 20min, and refrigerated at 4°C for 3 days to obtain alcohol-soluble protein-containing retrograded starch, gelatinized, high pressure, refrigerated retrograded for 7d, and then dried and crushed to obtain 565g of alcohol-soluble protein-containing retrograded starch. Weigh 300g coix seeds and 700g alcohol-soluble protein-containing retrograded starch, add 400ml tap water to coix seeds, soak at 40℃ for 4h, stir with alcohol-soluble protein-containing retrograded starch, mix well and transfer to a triangular flask and seal with cotton plug and newspaper; measure 40ml deionized water in a beaker and seal it with newspaper; at the same time, wrap the medicine spoon, glass rod, culture dish, spray bottle, etc. with newspaper; place the above items in a high-pressure steam sterilizer at 110℃ for 20min. Open the clean bench for ultraviolet sterilization for 30min, and use aseptic operation to pour the cooled deionized water into the Monascus slant culture medium and shake it to disperse the spores in the sterile water. Then put the spore-containing sterile water into the sterilized spray bottle, spray the Monascus spores into the conical flask and mix them evenly by stirring, and place it in a 32℃ constant temperature incubator for constant temperature culture for 33 days. After fermentation, the culture medium was placed in a 65°C oven to dry to constant weight, crushed through a 100-mesh sieve, and the resistant starch content was determined by enzymatic hydrolysis and weighing. The resistant starch content of the alcohol-soluble protein retrograded starch before Monascus fermentation was 38.32%, and the resistant starch content after fermentation was 67.82%.

Claims

1. A method for improving the purity of retrograded starch containing alcohol-soluble protein by using Monascus fermentation, characterized in that: The steps include: 1) corn amylose and alcohol-soluble protein component 3 (supernatant after cold precipitation of gluten alcohol extract, precipitate after freezing and thawing) are mixed in a mass ratio of 1:20 to 1:40, and stirred and mixed for 20 to 40 minutes in a water bath at 30 to 40°C to obtain low-viscosity alcohol-soluble protein component 3. Alcohol-soluble protein component 1 (precipitate after cold precipitation of gluten alcohol extract) accounts for 4%, low-viscosity alcohol-soluble protein 3 accounts for 1% and corn amylopectin accounts for 95%, and after gelatinization at 85°C for 30 minutes, wet heat high pressure treatment at 110°C for 20 minutes, cold storage at 4°C for 7 days, to obtain alcohol-soluble protein-containing retrograded starch; 2) Mix the alcohol-soluble protein-containing retrograded starch and coix seeds as a culture medium and sterilize them under high pressure. Dissolve the purified Monascus slant culture medium with sterile water on a sterile operating table, place it in a spray bottle after high pressure sterilization, spray it into the sterilized culture medium, and place it in a 32°C constant temperature incubator for fermentation for 20 to 33 days.

2. The method for improving the purity of retrograded starch containing alcohol-soluble protein by using Monascus fermentation according to claim 1, characterized in that: The Monascus purpureus is classified and named as Monascus purpureus, with a preservation number of CGMCC No. 40898, and is preserved in the General Microbiological Center of China National Committee for the Preservation and Administration of Microbiological Cultures.

3. The method for improving the purity of retrograded starch containing alcohol-soluble protein by using Monascus fermentation according to claim 1, characterized in that: The culture medium selected for Monascus fermentation is a mixture of alcohol-soluble protein retrograded starch and coix seeds in a mass ratio of 7:

3.

4. The method for improving the purity of retrograded starch containing alcohol-soluble protein by using Monascus fermentation according to claim 1, characterized in that: The coix seeds are soaked in 35-40°C tap water for 3-4 hours, and after being drained, the coix seeds are mixed with retrograded starch containing alcohol-soluble protein and placed in a high-pressure steam sterilizer, and the culture medium to be fermented is obtained after sterilization.

5. The method for improving the purity of retrograded starch containing alcohol-soluble protein by using Monascus fermentation according to claim 6, characterized in that: The sterilization temperature of the culture medium in a high-pressure steam sterilizer is 110° C., and the sterilization time is 20 to 40 minutes.

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