Red yeast rice soybean paste and preparation method thereof

Abstract

The present invention relates to the technical field of fermented food, and particularly discloses a red yeast rice soybean paste and a preparation method thereof, the preparation method comprises the following steps: oats are soaked and steamed, monascus is inoculated, solid state fermentation is performed for 8-12 days under the conditions of 28-32 DEG C and humidity of 75%-85%, the materials are turned over every day in the fermentation process, and atomized liquid containing 0.1%-0.3% of tea polyphenols is sprayed; soybeans are soaked in ultrasonic-assisted alkali liquor and then subjected to high-pressure cooking, and after cooling, the soybeans are mixed with red yeast rice according to the mass ratio of 5: 1-3: 1; adding 2%-5% of trehalose, 0.5%-1% of a protease preparation and table salt into the mixture, and performing two-stage fermentation at 40-45 DEG C; adding 0.1-0.5% of purple perilla seed extract, homogenizing, aging for 30 days, and sterilizing to obtain the red yeast rice soybean paste; according to the preparation method disclosed by the invention, oats are adopted as a monascus fermentation substrate, and atomization spraying treatment of tea polyphenol is combined, so that the content of functional components, such as Monacolin K and gamma-aminobutyric acid, in the monascus soybean paste is effectively increased, and not only is a product endowed with higher nutritional value, but also the monascus soybean paste has physiological activities of lowering lipid, promoting nerve health and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of fermented foods, and particularly relates to red yeast rice soybean paste and a preparation method thereof. Background Art

[0002] Soybean paste is a traditional fermented condiment made from soybeans through steaming, koji making, and fermentation. The traditional process usually involves mixing steamed soybeans with red yeast rice and salt, and then fermenting them at 30-40°C for 30-60 days through natural fermentation or artificial inoculation of Aspergillus oryzae and other strains. The finished product is rich in protein, amino acids, and red yeast metabolites (such as red yeast pigments), has a unique sauce flavor and a red appearance, and is widely used in the field of food seasoning.

[0003] Although the traditional process is mature, there are still significant defects in industrial production. Conventional red yeast rice is used to prepare red yeast rice, and the content of lipid-lowering active ingredients such as Monacolin K is generally ≤2.5mg / 100g. In addition, the product is easily contaminated by miscellaneous bacteria during the fermentation process, resulting in poor product stability. Summary of the invention

[0004] The object of the present invention is to provide a red yeast rice soybean paste and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing red yeast rice soybean paste comprises the following steps:

[0007] S1. Soak the oats and steam them, inoculate them with Monascus, and solid-state ferment them for 8-12 days at 28-32° C. and 75%-85% humidity. During the fermentation process, turn the oats over daily and spray them with atomized liquid containing 0.1%-0.3% tea polyphenols;

[0008] S2, the soybeans are soaked in ultrasonic-assisted alkali solution and then steamed under high pressure, and after cooling, mixed with the red yeast rice obtained in step S1 at a mass ratio of 5:1-3:1;

[0009] S3, adding 2%-5% trehalose, 0.5%-1% protease preparation and salt to the mixture, and performing two-stage fermentation at 40-45°C;

[0010] S4, adding 0.1%-0.5% perilla seed extract, aging for 30 days after homogenization, and sterilizing to obtain red yeast rice soybean paste.

[0011] Preferably, the oats in step S1 are pretreated with 0.5% citric acid solution, and the inoculation amount of Monascus is 3%-5% of the mass of the raw material.

[0012] Preferably, the ultrasonic treatment parameters in step S2 are: frequency 40 kHz, power 300 W, and the alkali solution is a sodium bicarbonate solution with a pH of 8.5-9.0.

[0013] Preferably, the protease preparation in step S3 is a complex of neutral protease and flavor protease, with a mass ratio of 2:1.

[0014] Preferably, the perilla seed extract in step S4 is prepared by supercritical CO 2 Prepared by extraction method, containing rosmarinic acid ≥ 15%.

[0015] A red yeast rice soybean paste prepared by any of the above methods, characterized in that its active ingredients include Monacol in K ≥ 5 mg / 100 g, γ-aminobutyric acid ≥ 50 mg / 100 g, color L value ≥ 65, and a value ≥ 12.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) By using oats as the substrate for red yeast rice fermentation and combining it with atomized spraying of tea polyphenols, the content of functional ingredients in red yeast rice soybean paste, such as monacolin K and γ-aminobutyric acid, is effectively increased, which not only gives the product a higher nutritional value, but also has physiological activities such as lowering blood lipids and promoting nerve health.

[0018] (2) Through the processes of ultrasonic-assisted alkaline solution soaking of soybeans, two-stage fermentation, and the addition of perilla seed extract, the problems of traditional soybean paste, such as dark color, rough taste, and strong bean smell, were improved, the sensory quality of the product was improved, and its stability and storage resistance were enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Embodiment 1:

[0022] See also Figure 1 As shown, the preparation steps of red yeast rice soybean paste are as follows:

[0023] S1. Preparation of red yeast rice: 500 g of oats were soaked in 0.5% citric acid solution for 30 minutes, drained and steamed to a water content of 45%; Monascus M-2023 strain (inoculation amount 4%) was inoculated and spread on a fermentation plate, and the temperature and humidity were controlled at 30°C and 80% respectively; after turning the material every day, an atomized liquid containing 0.2% tea polyphenols (spraying amount 10 mL / kg raw material) was sprayed and fermented for 10 days to obtain a red yeast rice product;

[0024] S2. Soybean pretreatment: 1 kg of soybean was soaked in a sodium bicarbonate solution with a pH of 8.8 and ultrasonically treated (40 kHz, 300 W) for 30 minutes; steamed at 121° C. for 20 minutes, cooled to room temperature and mixed in a ratio of red yeast rice to soybean of 3:1;

[0025] S3, composite fermentation: adding 3% trehalose, 0.8% protease preparation (neutral protease: flavor protease = 2:1), 8% salt; fermentation in two stages, the first stage is aerobic fermentation at 45°C for 3 days (stirring twice a day); the second stage is anaerobic fermentation at 40°C for 18 days after sealing;

[0026] S3, post-ripening treatment: Mix in 0.3% perilla seed extract (supercritical CO 2 extraction, rosmarinic acid content 18%); after homogenization, aging at 25° C. in the dark for 30 days, and pasteurization at 85° C. for 15 minutes to obtain red yeast rice soybean paste.

[0027] Embodiment 2:

[0028] The difference from Example 1 is that, in the red yeast fermentation, the inoculation amount of red yeast is 3%, the fermentation is carried out at 28° C. for 8 days, and 0.1% tea polyphenols atomized liquid is sprayed;

[0029] Soybean treatment: red yeast rice: soybean = 5:1, ultrasonic power 250W;

[0030] Composite fermentation: add 2% trehalose and 0.5% protease, aerobic fermentation at 45℃ for 3 days + anaerobic fermentation at 40℃ for 15 days;

[0031] Perilla seed extract added at 0.1%;

[0032] Embodiment three:

[0033] The difference from Example 1 is that, in the red yeast fermentation, the inoculation amount of red yeast is 5%, the fermentation is carried out at 32° C. for 12 days, and 0.3% tea polyphenols atomized liquid is sprayed;

[0034] Soybean treatment: red yeast rice: soybean = 1:1, ultrasonic power 350W;

[0035] Composite fermentation: add 5% trehalose and 1% protease, aerobic fermentation at 45℃ for 3 days + anaerobic fermentation at 40℃ for 20 days;

[0036] Perilla seed extract added at 0.5%;

[0037] Comparative Example 1:

[0038] The red yeast rice matrix is ​​rice, and no tea polyphenols are added during fermentation; the soybeans are only cooked at normal pressure without ultrasonic treatment; there is no trehalose and segmented temperature control during the fermentation stage; and no perilla seed extract is added during post-ripening.

[0039] Experimental example:

[0040] S1 sensory flavor evaluation

[0041] Ten trained sensory evaluators (aged 25-50 years old, without taste / smell disorders) were selected to conduct independent blind evaluations using a 5-point scale (1 = poor, 5 = excellent). The evaluation indicators included: color (red brightness, uniformity), aroma (rich sauce aroma, no unpleasant odor), taste (salty and fresh harmony, sweet aftertaste), mouthfeel (fineness, no graininess), and overall acceptance (comprehensive preference).

[0042] The specific data are shown in the following table:

[0043] Evaluation indicators Example 1 Example 2 Example 3 Comparative Example 1 Color 4.8 4.5 4.6 3.2 aroma 4.7 4.3 4.5 3.0 smell 4.6 4.2 4.4 2.8 Taste 4.5 4.0 4.3 2.5 Overall acceptance 4.7 4.3 4.5 2.7

[0044] As can be seen from the above, the sensory scores of Examples 1-3 are significantly higher than those of Comparative Example 1 (p<0.05), and Example 1 is the best overall.

[0045] Comparative Example 1 has problems such as dark color (score 3.2) and residual beany smell (aroma 3.0) because no functional ingredients (such as perilla seed extract) are added and the process is simplified.

[0046] S2 physical and chemical index analysis

[0047] The color was measured by a colorimeter (CIELab colorimetric system, L value represents brightness, a value represents red-green color); the total amount of free amino acids was measured by ninhydrin colorimetry (GB5009.124-2016); volatile flavor substances were measured by headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS); the texture characteristics were measured by a texture analyzer to determine viscosity and hardness (probe P / 5, test speed 1mm / s); the salt content was measured by silver nitrate titration (GB5009.44-2016);

[0048] The specific data are shown in the following table:

[0049]

[0050] As can be seen from the above, in Example 1, due to the atomization treatment of tea polyphenols to inhibit oxidation, the red pigment of monascus (a value ≥ 12) is significantly higher than that of comparative example 1 (8.7), and the brightness (L value ≥ 65) is significantly improved; the volatile ester substances (such as ethyl acetate and ethyl lactate) in Example 1 are 2.26 times that of comparative example 1, giving the product a richer sauce and fruity aroma;

[0051] Since comparative example 1 did not use ultrasonic pretreatment, the soy protein dissolution rate was low (63%), resulting in high viscosity (4200 mPa·s) and obvious granularity; Example 1 optimized the enzymatic hydrolysis effect by staged fermentation, and the salt content was reduced to 8.2% (9.0% in comparative example 1), and the salty taste was softer.

[0052] The comparison of S3 functional ingredients is shown in the following table;

[0053] Element Example 1 Comparative Example 1 Increase multiple Monacolin K 5.8mg / 100g 2.1mg / 100g 2.76 times Gamma-aminobutyric acid (GABA) 68mg / 100g 29mg / 100g 2.34 times Rosmarinic acid 0.32mg / g Not detected

[0054] As can be seen from the above, Example 1 uses oat matrix + tea polyphenols atomization to promote the synthesis of secondary metabolites of Monascus; the two-stage fermentation (aerobic→anaerobic) creates pH and temperature conditions that are conducive to the production of GABA; and rosmarinic acid has a synergistic antioxidant effect.

[0055] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing red yeast rice soybean paste, characterized in that: The following steps are involved: S1. Soak the oats and steam them, inoculate them with Monascus, and solid-state ferment them for 8-12 days at 28-32° C. and 75%-85% humidity. During the fermentation process, turn the oats over daily and spray them with atomized liquid containing 0.1%-0.3% tea polyphenols; S2, the soybeans are soaked in ultrasonic-assisted alkali solution and then steamed under high pressure, and after cooling, mixed with the red yeast rice obtained in step S1 at a mass ratio of 5:1-3:1; S3, adding 2%-5% trehalose, 0.5%-1% protease preparation and salt to the mixture, and performing two-stage fermentation at 40-45°C; S4, adding 0.1%-0.5% perilla seed extract, aging for 30 days after homogenization, and sterilizing to obtain red yeast soybean paste.

2. The method for preparing red yeast rice soybean paste according to claim 1, characterized in that: In step S1, the oats are pretreated with 0.5% citric acid solution, and the inoculation amount of Monascus is 3%-5% of the mass of the raw material.

3. The method for preparing red yeast rice soybean paste according to claim 1, characterized in that: The ultrasonic treatment parameters in step S2 are: frequency 40kHz, power 300W, and the alkali solution is a sodium bicarbonate solution with a pH of 8.5-9.

0.

4. The method for preparing red yeast rice soybean paste according to claim 1, characterized in that: The protease preparation in step S3 is a complex of neutral protease and flavor protease, with a mass ratio of 2:

1.

5. The method for preparing red yeast rice soybean paste according to claim 1, characterized in that: The perilla seed extract in step S4 is prepared by supercritical CO2 extraction and contains rosmarinic acid ≥ 15%.

6. A red yeast rice soybean paste prepared according to any one of claims 1 to 5, characterized in that: Its active ingredients include Monacolin K≥5mg / 100g, γ-aminobutyric acid≥50mg / 100g, color L value≥65, and a value≥12.

Images