CN113061536B

CN113061536B - Monascus purpureus Z-27 capable of producing lovastatin at high yield and application thereof

Info

Publication number: CN113061536B
Application number: CN202110330370.1A
Authority: CN
Inventors: 毛健; 刘双平; 吴玉峰
Original assignee: Jiangnan University
Current assignee: Jiangnan University
Priority date: 2021-03-17
Filing date: 2021-03-17
Publication date: 2022-08-23
Anticipated expiration: 2041-03-17
Also published as: CN113061536A

Abstract

The invention discloses a high-yield lovastatin-producing monascus purpureus Z-27 and application thereof, belonging to the field of fermentation engineering and biotechnology. The purple monascus which has improved lovastatin yield, monascus pigment synthesis, stability and the like and does not produce citrinin is obtained by ultraviolet mutagenesis screening. In the preparation of the red yeast starter by utilizing the solid state fermentation of the monascus purpureus, the yield of lovastatin can reach 20-24 mg/g, the color value can reach 3000-3200 mu/g, and the lovastatin and the color value are all at a higher level and are not detected by citrinin. Moreover, the bacterial strain or the leaven is applied to the preparation of fermented foods such as yellow wine, thick broad-bean sauce, soy sauce, table vinegar and bread, so that citrinin is not detected, and the yield of lovastatin can reach 40.70 mg/g. Has wide industrial application prospect.

Description

Monascus purpureus Z-27 capable of producing lovastatin at high yield and application thereof

Technical Field

The invention relates to a high-yield lovastatin monascus purpureus Z-27 and application thereof, belonging to the field of fermentation engineering and biotechnology.

Background

Red yeast is a characteristic traditional fermented food created by the precedent of China, and integrates various food and medicine functions. The red yeast is a unique yeast which is prepared by taking rice as a main raw material and fermenting the rice by monascus, is rich in natural red pigment, has medicinal and health-care values, and is mainly applied to the aspects of wine brewing, medicines, food additives and the like. The monascus, a unique fermentation strain in red yeast, is metabolized during fermentation to produce a plurality of physiologically active substances beneficial to human bodies, such as lovastatin, which is a highly concerned functional component in red yeast. Lovastatin has been widely regarded and favored because of its significant lipid-lowering efficacy against the cause of disease, high safety, good tolerability, and the like.

The lovastatin is mainly generated by metabolism of microorganisms, the main fermentation modes are solid state fermentation and liquid state fermentation, the content of the lovastatin generated by the red yeast solid state fermentation is far higher than that of the lovastatin generated by the liquid state fermentation, the solid state fermentation is still the common production method of functional red yeast at present, and with the increasing demand for red yeast products in China at home and abroad, how to effectively improve the yield of the lovastatin generated by the functional monascus solid state fermentation becomes the problem to be solved urgently in the development of the red yeast fermentation industry. However, the problems of low yield, high cost and the like generally exist in industrial production of lovastatin and monascus pigment in China, so that the breeding of the excellent functional monascus strain with high lovastatin yield is a key factor of industrial production and has important practical application significance.

In recent years, a great deal of research is carried out on the breeding of high-yield lovastatin monascus strains at home and abroad, and the methods such as gamma ray, UV, protoplast fusion technology, genetic engineering transformation, mutagen and the like are mainly utilized. And a favored traditional physical mutagenesis method in industrial production is adopted to breed the functional monascus strain with stable and high yield of lovastatin, thereby having important significance for further developing monascus strain resources and application research thereof.

Disclosure of Invention

In view of the fact that monascus strains in the prior art are not high in stability and the yield of lovastatin is generally not suitable for the requirement of industrial production, the purple monascus which is improved in the aspects of lovastatin yield, monascus pigment synthesis, stability and the like and does not produce citrinin is obtained through ultraviolet mutagenesis screening.

The invention provides a Monascus purpureus (Monascus purpureus) which is preserved in China center for type culture collection (CCTCC NO: M2021198) at 3 months and 1 day 2021.

The invention provides a starter, which contains the monascus purpureus.

In one embodiment, the number of spores per gram of starter culture≥1.0×10 ⁶ 。

The invention provides a method for preparing the leaven, rice is sterilized, the water content is adjusted to 40% -50%, a fermentation culture medium is prepared, the monascus purpureus of claim 1 is added into the fermentation culture medium, and the fermentation is carried out for 15-20 days.

In one embodiment, the Monascus purpureus went of claim 1 is treated at a ratio of 1.0X 10 or more ⁶ The spores are added to the fermentation medium in an amount of one spore/g dry weight of rice.

In one embodiment, the fermentation process comprises standing at 28-30 deg.C for 24-48 hr, shaking, and spreading; after that, shaking the flask for 1 to 2 times every 18 to 24 hours, and finishing the fermentation for 14 to 18 days to prepare the leaven.

The invention provides a method for preparing fermented food, which prepares food by fermenting the monascus purpureus or the leaven.

In one embodiment, the raw materials of the fermented food include rice, flour, and soybean.

In one embodiment, the fermented food product comprises wine, bread, soy sauce, thick broad-bean sauce, vinegar.

The invention provides application of the monascus purpureus or the leavening agent in preparation of fermented foods.

In one embodiment, the fermented food comprises yellow wine, bread, soy sauce, thick broad-bean sauce, vinegar.

The invention has the beneficial effects that:

(1) the invention provides monascus purpureus Z-27, wherein the yield of lovastatin in a monascus leaven prepared by solid-state fermentation of monascus purpureus can reach 20-24 mg/g, the color value can reach 3000-3200 mu/g, and the monascus purpureus are all at a higher level and have no citrinin detection. Can be widely applied to the fields of food, wine brewing and the like, can improve the color of the fermented product, and improves the performance of the fermented product in the aspects of health care and safety.

(2) The starter prepared by the monascus purpureus is used for preparing the red yeast yellow wine and the red yeast vinegar, so that the content of lovastatin in the red yeast yellow wine and the red yeast vinegar is obviously increased, the health care function of the product is improved, and the lovastatin is not detected in most commercially available red yeast yellow wine and red yeast vinegar.

Biological material preservation

The Monascus purpureus is classified and named as Monascus purpureus Z-27, and has been preserved in the China Center for Type Culture Collection (CCTCC) No. M2021198 in 2021, 3 months and 1 days, with the preservation number being M2021198 and the preservation address being Wuhan university, Wuhan, China.

Drawings

FIG. 1 is the ultraviolet radiation lethality curve of the original monascus strain.

FIG. 2 is a chromatogram of a lovastatin standard determined by HPLC.

FIG. 3 is a standard curve of lovastatin standard as determined by HPLC.

FIG. 4 shows the solid-state fermentation conditions of the original strain and the positive mutant strain to produce lovastatin (a), monascorubin (b) and citrinin (c).

FIG. 5 shows the production of saccharifying enzyme (a), liquefying enzyme (b) and acid protease (c) by solid state fermentation of starting strain and positive mutant strain.

Detailed Description

PDA flat panel: 200g of potato (peeled), 15-20g of cane sugar, 20-30g of agar and 1000mL of distilled water, and the pH value is natural.

Liquid phase assay method of lovastatin: weighing 0.5g of red yeast powder by HPLC method, placing in a 50mL centrifuge tube, adding 30mL of methanol, shaking in a 50 deg.C shaking water bath for 2h, shaking, centrifuging at 8000r/min at normal temperature for 5min, and filtering the supernatant with 0.22 μm microporous membrane. Chromatographic conditions are as follows: a chromatographic column: athena C18-WP (250 mm. times.4.6 mm, 5 μm); mobile phase: acetonitrile-0.1% phosphoric acid in water (65: 35, V/V); flow rate: 1.0 mL/min; ultraviolet detection wavelength: 238 nm; sample introduction amount: 5 mu L of the solution; column temperature: (30.0 +/-0.5) DEG C. Preparing 400mg/L lovastatin standard stock solution with 70% ethanol solution, diluting at equal ratio to obtain lovastatin standard working solution with concentration of 3.125, 6.25, 12.5, 25, 50, 100, 200, and 400mg/L, respectively, and performing external standard quantification. Taking the concentration of lovastatin as a horizontal coordinate (X) and the peak area as a vertical coordinate (Y), obtaining a regression equation as follows: y is 1.55X 10 ⁴ X-2.96×10 ⁴ ，R ² 0.9995. Pressing markAnd solving the lovastatin concentration in the sample by a quasi-curve regression equation.

The citrinin determination method comprises the following steps: the method is carried out according to GB/T5009.222-2008 'determination of citrinin in red yeast products'.

The method for measuring the color value comprises the following steps: according to the color value detection method in GB 1886.19-2015 food additive Red Yeast Rice.

Measurement of glycation ability: the method is carried out by referring to a method for detecting the saccharifying power in light industry standard QB/T5188-2017 red yeast brewing.

The method for measuring the liquefying capacity and the acid protease activity comprises the following steps: the method is carried out according to the detection method of amylase and protease in QB 1803-93 general test method for industrial enzyme preparations in the light industry.

Alcohol content, pH, total acid and amino acid nitrogen determination: detection is carried out according to GB/T13662-.

Example 1: ultraviolet mutagenesis and screening

Step 1, preparation of starting strain spore liquid:

inoculating the original red yeast strain on a PDA culture medium, culturing at 28 ℃ for 7 days, scraping hyphae and spores by using an inoculating shovel, transferring into a triangular flask filled with 30mL of sterile water, spreading small glass beads at the bottom of the triangular flask, shaking at 180r/min for 20min, fully scattering the spores, and filtering by using 2 layers of sterile mirror paper to prepare uniform spore suspension. Final dilution adjustment to give a spore concentration of 10 ⁶ Suspension per mL.

Step 2, determination of ultraviolet mutagenesis time:

and (3) switching on an ultraviolet lamp for 30min to stabilize light waves, absorbing 5mL of spore suspension in a sterile culture dish in a lightproof sterile operating platform, placing the sterile culture dish on a magnetic stirrer, adding a sterilization pin into the culture dish, and starting the stirrer to keep the monospore suspension in a stirring state all the time. The sterile culture dish filled with the spore liquid is vertically placed at a position 20cm below an ultraviolet lamp (15W), the dish cover is opened under the dark condition, the irradiation time is 1, 2, 3, 4, 5 and 6min, and the sampling is carried out once every 30 s.

Adding sterile water into the strain suspension subjected to mutagenesis treatment for proper dilution, sucking 0.1mL of the strain suspension, coating the strain suspension on a PDA (personal digital Assistant) plate, taking the original strain solution which is not subjected to ultraviolet irradiation and diluted by the same gradient to coat the plate as a control, standing the uniformly coated plate for 20min, and performing inverted culture for 4-5d under the condition of 28 ℃ and light shielding (wrapping by tinfoil), wherein each group is 3 in parallel. Observing the growth condition of colonies, counting, calculating the lethality rate, drawing an ultraviolet irradiation lethality rate curve, generally adopting a plate colony with higher lethality rate to continue subsequent experiments in order to improve the mutagenesis success rate, but the mutant strain on the plate with the excessively high lethality rate is easy to generate the condition of back mutation, and the character is unstable. Therefore, the ultraviolet irradiation time with the lethality of 80% -90% is determined, and according to the lethality curve of figure 1, the mutagenesis effect is better when the irradiation time is selected to be 240 s.

Step 3, screening positive mutant strains after ultraviolet mutagenesis

Plate separation preliminary screening: adding sterile water into the spore bacterial liquid subjected to ultraviolet irradiation for a certain time (the ultraviolet irradiation time determined in the step 2), properly diluting, sucking 0.1mL of the spore bacterial liquid, coating the diluted spore bacterial liquid on a PDA (personal digital assistant) plate and a lovastatin resistant plate, respectively, coating the lovastatin resistant culture medium on the PDA plate and the lovastatin resistant plate, taking the mixture as a blank control after diluting the original bacterial liquid with the same gradient as that of the original bacterial liquid without mutagenesis, wrapping the mixture with tinfoil at 28 ℃ and culturing the mixture in a dark place for 4-5 days, and enabling three groups to be parallel. Observing the colony growing on the plate by taking the colony morphology of the original strain as a reference, and selecting the strain which is earlier than the pigment producing time of the original strain and has dark color to a fresh PDA culture medium.

Solid state fermentation and re-screening: washing spores on the lower bevel with 0.1% sterile Tween water, soaking 30g semen oryzae for 2h, transferring into 250mL conical flask, sealing, sterilizing at 121 deg.C and 0.08MPa for 20min, scattering rice grains, and inoculating for 10% ⁶ Inoculating spores per gram (dry weight of rice) in a solid fermentation culture medium cooled to room temperature, and supplementing sterile water to keep the water content at 40-50%; after being stirred evenly, the culture medium is piled up to one corner in a bottle, and is kept stand and cultured for 24-48h at the temperature of 28-30 ℃ and then is shaken and spread out; shaking for 1-2 times every 18-24h until 14-18d fermentation is finished, making into red rice, and oven drying.

Measuring the lovastatin content, the color value and the citrinin content in the red yeast starter; and (4) measuring the content of saccharifying enzyme, liquefying enzyme and acid protease in the red yeast starter.

The results of the screening of the positive mutant strain by solid state fermentation are shown in FIG. 4, wherein the red yeast starter obtained by fermenting the monascus Z-27 has higher lovastatin and color value levels, and the average lovastatin content reaches 23.41mg/g, which is much higher than the lovastatin content of commercial red yeast. The red color value can reach 3081.43 mu/g, and the red rice conforms to national standard of red yeast rice in China (GB 1886.19-2015). The strain Z-27 does not produce citrinin, and the limit of citrinin in functional red yeast rice in QBT 2847-2007 functional red yeast rice is 50 mug/kg, which meets the light industry standard. Therefore, Z-27 is preferably selected as a high-yield lovastatin monascus.

Step 4, genetic stability test of mutant strains

Carrying out subculturing on the screened mutant monascus strain Z-27 with high yield of lovastatin and pigment on a PDA culture medium for 6 generations, carrying out constant-temperature cultivation at 28 ℃ for 7 days in each generation, carrying out solid-state fermentation for 14 days in each generation, detecting the pigment producing capability and the lovastatin content of each generation of strain, and screening out the strain with the best performance and the best genetic stability.

TABLE 1 results of solid state fermentation of mutant strain Z-27 to produce lovastatin, monascus pigment and citrinin

Example 2: preparation of red yeast starter

The monascus Z-27 is streaked on the slope of wort, and cultured at 25-30 deg.C for 7-10 days until the monascus spores. Washing spores on the lower inclined surface with 0.1% sterile tween water, soaking 100g of long-shaped rice for 2h, transferring into 1000mL conical flask, sterilizing at 121 deg.C and 0.08MPa for 20min, beating rice grains while hot, adding sterile water to adjust water content to 40% -50% to obtain long-shaped rice fermentation culture medium, inoculating 10% sterile tween water to the culture medium, and culturing ⁶ Inoculating spores/g (dry weight of rice) into indica rice fermentation culture medium cooled to room temperature, mixing, stacking the culture medium to one corner in a bottle, standing at 28-30 deg.C for 24-48h, shaking, and spreading; then shaking the flask for 1-2 times every 18-24h, ending the fermentation for 14-18d, and preparing the monascus leaven.

Example 3: application of monascus purpureus Z-27 prepared monascus purpureus starter in monascus yellow wine

Brewing the red yeast rice wine by using a red yeast rice starter prepared from the monascus purpureus:

taking sticky rice (mass g) as a reference, uniformly mixing steamed rice (140%), activated yeast (10%), wheat starter (5%), red yeast (8%), water (123%) and the like, and blanking. Pre-fermentation is carried out for 4 days at 28 ℃, and harrowing is carried out every day; after-fermentation is carried out for 20d at 15 ℃, and the harrowing interval is 2 d. Squeezing out wine base after fermentation, sterilizing in 80 deg.C water bath for 30min, cooling, and sealing. Sampling and detecting alcohol content, pH, total acid, amino acid nitrogen, lovastatin, color value, citrinin and other indexes in the wine sample.

Through detection, the alcoholic strength of the wine reaches 13.5% vol, the pH value is 4.32, the total acid content is 4.73g/L, and the amino acid nitrogen content is 0.72g/L, which all reach the national standard. The lovastatin content reaches 77.45mg/L, the color value reaches 20.99 mu/mL, and no citrinin is detected.

Example 4: application of monascus purpureus Z-27 prepared monascus purpureus starter in monascus yellow wine

The red yeast rice wine is brewed by using a red yeast starter prepared from monascus purpureus, and steamed rice (140%), activated yeast (10%), wheat starter (5%), red yeast (10%), water (123%) and the like are uniformly mixed and blanked by taking sticky rice (sticky rice dry weight g) as a reference. Pre-fermentation is carried out for 4 days at 28 ℃, and harrowing is carried out every day; after-fermentation is carried out for 20d at 15 ℃, and the harrowing interval is 2 d. Squeezing out wine base after fermentation, sterilizing in 80 deg.C water bath for 30min, cooling, and sealing. Sampling and detecting the indexes of alcoholic strength, total acid, amino acid nitrogen, lovastatin, color value, citrinin and the like in the wine sample.

Through detection, the alcoholic strength of the wine reaches 14.2% vol, the total acid content is 4.80g/L, and the amino acid nitrogen content is 0.79g/L, which all reach the national standard. The lovastatin content reaches 80.97mg/L, the color value reaches 23.11 mu/mL, and no citrinin is detected.

Example 5: application of red yeast starter prepared from monascus purpureus Z-27 in red yeast vinegar

The same dropping ratio as in example 3 was used to conduct the saccharification alcohol fermentation at 28 ℃ for 8 days to obtain a fermented mash. The fermented liquor is used as a substrate for liquid submerged fermentation of the red yeast vinegar, and 10% acetic acid bacteria liquid is inoculated for acetic acid fermentation for 15 d. And then adding salt with the concentration of 4%, tightly covering a cylinder cover, standing for 2 days, pouring vinegar by adopting a three-set circulation method of a pouring cylinder, firstly adding tap water into the third group of fermented grains, pouring a pouring liquid, adding the pouring liquid into the second group of fermented grains, soaking for 10 hours, pouring out secondary vinegar, adding the secondary vinegar into the first group of fermented grains, soaking for 20 hours, and then pouring out to obtain primary vinegar. Sterilizing at 90 deg.C for 30min, cooling, clarifying, loading into jar, and sealing. The prepared red yeast vinegar has lovastatin content of 72.78mg/L and no citrinin detection.

Example 6: application of red yeast starter prepared from monascus purpureus Z-27 in red yeast vinegar

The same dropping ratio as in example 4 was applied to the saccharified alcohol fermentation at 28 ℃ for 8 days to obtain a fermented mash. The fermented mash is used as a substrate for liquid submerged fermentation of the monascus vinegar, and 10% acetic acid bacteria liquid is inoculated for acetic acid fermentation for 15 d. And then adding salt with the concentration of 4%, tightly covering a cylinder cover, standing for 2 days, pouring vinegar by adopting a three-set circulation method of a pouring cylinder, firstly adding tap water into the third group of fermented grains, pouring a pouring liquid, adding the pouring liquid into the second group of fermented grains, soaking for 10 hours, pouring out secondary vinegar, adding the secondary vinegar into the first group of fermented grains, soaking for 20 hours, and then pouring out to obtain primary vinegar. Sterilizing at 90 deg.C for 30min, cooling, clarifying, filling into jar, and sealing. The prepared red yeast vinegar has lovastatin content of 78.49mg/L and no citrinin detected.

Example 7: application of monascus purpureus Z-27 prepared red rice starter in soy sauce

Selecting bean materials: selecting plump soybean, cleaning, soaking in water for 3-5 hr until no wrinkles, draining water, steaming under pressure until cooked, and separating with fingers.

Preparing yeast: mixing bran, flour and water, steaming for 1h at normal pressure, stewing for 30min, taking out of a pot, sieving, transferring to a mixing table, spreading, properly stirring for quick cooling, inoculating 0.2-0.5% of strain in a triangular flask at 30-40 ℃, uniformly stirring, and uniformly distributing aspergillus oryzae spores on yeast materials. And after inoculation, putting the mixture into a bent board, keeping the product temperature not lower than 25 ℃, the material thickness of the mixture at 1-1.5 cm, keeping the room temperature at 28-30 ℃, and culturing for about 16 hours. When the product temperature rises to about 36 ℃ and the surface layer of the yeast material is slightly whitish and caked, carrying out primary yeast turning, keeping the room temperature at 28-30 ℃, after yeast turning for 4-5 hours, raising the product temperature to about 36 ℃, then carrying out secondary yeast turning, and changing the positions of the yeast trays up and down and keeping the positions at 32-35 ℃. After inoculating, putting into a curved plaque, culturing for 65h, taking off the screen, and transferring into a dry, shady and ventilated room for standby, wherein the storage time is less than 10 d.

Inoculating and mixing flour: after the cooked soybeans are taken out of the pot, the soybeans enter an air cooling machine through a hopper for cooling, the temperature of the cooked soybeans is adjusted to be below 45 ℃, and then the cooked soybeans are mixed with flour and inoculated through a starter propagation machine. The yeast powder is mixed with proper amount of flour in advance and stirred evenly, and the usage amount of the yeast powder is 0.2-0.4%.

Fermentation: the naturally sun-cured soy sauce adopts a 'sun-cured in the day and exposed at night' in-jar fermentation process (fermentation is carried out at the temperature of 30 ℃). The content of mature amino acid nitrogen in the headgear oil is more than 1.0g/100 mL. Sampling and testing after the headgear oil is fermented to be mature, and spraying the headgear oil for later use after the headgear oil is determined to be qualified.

And (3) adding sugar and sun-curing: adding white sugar, brown sugar, maltose, high fructose syrup, glucose and other sugars or sugar of combined components in a proper proportion into the leached headgear oil, and sun-drying for 2-3 months until the color of the soy sauce reaches 2000 EBC.

Adding yeast and sun-curing: after the color intensity of the soy reaches 2000EBC, adding a certain amount of red yeast rice or the particles and the extract of the red yeast rice after the red yeast rice is ground, and drying in the sun until the red index reaches the requirement.

And (3) finished product: heating for sterilization, preparation and clarification.

When the color of dark soy sauce is above 2000EBC, adding OD into soy sauce per ml according to the requirements of finished product color and red index ₄₃₀ 40 monascus pigment can meet relevant requirements, and then the finished soy sauce with rich color can be obtained through the traditional sun-curing method. The prepared soy sauce adopts monascus pigment to replace artificial caramel pigment, wherein the content of lovastatin is 68.30mg/L, and no citrinin is detected.

Example 8: application of red yeast rice starter prepared from monascus purpureus Z-27 in soybean paste

Pretreatment of raw materials: the selected soybean is northeast high-quality soybean, is required to be fresh, has full grains, and is free from mildew, rot and worm damage; the selected flour and salt are high-quality flour sold in the market and refined salt without iodine. Cleaning high-quality fresh northeast soybean, removing soil and impurities on the surface and floating substances on the surface, soaking in water until the soybean has no white core, and kneading into two pieces with hands.

And (3) cooking: steaming at normal pressure until the soybean is completely and uniformly cooked, and the soybean is soft and not rotten, and the whole grains are kept without filling.

Preparing yeast: the method adopts a aspergillus oryzae and aspergillus niger double-strain koji making mode, soybean and cooked flour are used as main raw materials, aspergillus oryzae and aspergillus niger double-strain koji making (the mass ratio is 1:1) is carried out, the inoculation amount is 0.04%, monascus strain spore liquid Z-27 is added, the koji making time is 28 hours, the koji making temperature is 36-38 ℃, the pH value is close to 6, the inoculation amount is 0.3% of a mixed material, the soybean and flour are 6:4 (mass ratio), and the activity of enzyme in the mixed koji is higher than that of single aspergillus oryzae. A certain amount of cooked flour is added in the starter propagation process, so that the moisture of the starter propagation material can be adjusted, and the growth of monascus is facilitated. Monascus can produce a secondary metabolite monascus pigment in the metabolic process, and endows the thick broad-bean sauce with unique color.

Fermentation: the traditional fermentation is carried out by a solid low-salt method. The prepared bean paste has the characteristics of ruddy color, mellow taste, strong aroma and the like, wherein the content of lovastatin reaches 62.50mg/L, and no citrinin is detected.

Example 9: application of monascus purpureus Z-27 prepared red yeast starter in fermented bean curd

Putting the pickled salted germs (about 22g each) which are inoculated with mucor for fermentation and mature, cooled, rubbed and salted into a jar, adding soup bases prepared by grinding yellow wine, rose and red yeast rice into pulp, immersing, sealing the jar at normal temperature and fermenting for more than 6 months to obtain the finished rose fermented bean curd. The prepared red yeast fermented bean curd has lovastatin content of 107.48mg/L and no citrinin detection.

Example 10: application of red yeast rice leaven prepared from monascus purpureus Z-27 in bread

Powder mixing: 1000-1200 g of flour, 40-45 g of granulated sugar, 100-110 g of milk, 50-60 g of cream, 20-25 g of salt, 8-10 g of yeast, 8-10 g of malt extract, 600-700 g of water and 5-10 g of red yeast powder are blended.

And (3) secondary fermentation: fermenting at 28 deg.C for 1 hr, fermenting at 28 deg.C for 0.5 hr, and concocting and shaping.

And (3) proofing: fermenting for 1-1.2 h at 37 ℃.

Baking: baking at 180 ℃ for 15-20 min, and cooling to obtain a finished product. The prepared bread has lovastatin content of 40.70mg/g, and no citrinin is detected.

Example 11: application of red yeast rice leaven prepared from monascus purpureus Z-27 in bread

Powder mixing: 1000-1200 g of flour, 40-45 g of granulated sugar, 100-110 g of milk, 50-60 g of cream, 20-25 g of salt, 8-10 g of yeast, 8-10 g of malt extract, 600-700 g of water and 20-30 mL of red yeast water extract are blended.

And (3) fermentation: fermenting for 1-1.2 h at 37 ℃.

Baking: baking at 180 ℃ for 15-20 min, and cooling to obtain a finished product. The prepared bread has lovastatin content of 45.12mg/g, and no citrinin is detected.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by one skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. Monascus purpureus strain (A)Monascuspurpureus) Z-27, which has been preserved in China center for type culture Collection at 3 months and 1 day 2021, with the preservation number of CCTCC NO: m2021198.

2. A fermentation agent comprising the Monascus purpureus strain of claim 1.

3. The starter culture according to claim 2, wherein the starter culture is a yeast strainCharacterized in that the number of spores in each gram of the leaven is more than or equal to 1.0 multiplied by 10 ⁶ 。

4. The method for preparing the leaven of claim 2 or 3, wherein rice is sterilized and the water content is adjusted to 40% to 50%, the monascus purpureus of claim 1 is added to the sterilized rice, and the fermentation medium is fermented for 15 to 20 days to prepare the fermentation medium.

5. The method according to claim 4, wherein the red koji mold of claim 1 is cultured at a temperature of not less than 1.0X 10 ⁶ The spores are added to the fermentation medium in an amount of one spore/g dry weight of rice.

6. The method of claim 5, wherein the fermentation process comprises standing at 28-30 deg.C for 24-48h, shaking, and spreading; after that, shaking the flask for 1 to 2 times every 18 to 24 hours, and ending the fermentation for 14 to 18 days to prepare the leaven.

7. A method for producing fermented foods, characterized in that foods are produced by fermenting the red koji mold of claim 1 or the starter of claim 2 or 3.

8. The method according to claim 7, wherein the raw material of the fermented food is rice, flour or soybean.

9. The method of claim 8, wherein the fermented food is an alcoholic liquor, bread, soy sauce, bean paste or vinegar.

10. Use of the monascus purpureus of claim 1, or the starter culture of claim 2 or 3 in the preparation of fermented food products.