Lychee seed red yeast rice product as well as preparation method and application thereof

Abstract

According to the lychee seed monascus product and the preparation method and application thereof, starch in lychee seeds is converted into active substances such as monascus pigment and lovastatin through monascus, and the compact structure of the lychee seeds is destroyed through the combined action of various enzymes in the monascus, so that combined flavone in cells is changed into free flavone; according to the present invention, the lychee seed is used as the raw material, such that the dissolution of flavone is promoted, and the red yeast rice product containing lovastatin and flavonoid substances is obtained, such that compared with the common red yeast rice, the lychee seed red yeast rice product does not only produce the functional components such as lovastatin, monascus pigment and the like during the fermentation process, but also can make full use of the original active components in the lychee seed, the total utilization value of litchis is improved, waste is turned into wealth, and resource waste is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of bacterial fermentation, and particularly relates to a litchi seed red yeast rice product and a preparation method and application thereof. Background Art

[0002] In recent years, with the continuous improvement of living standards, diseases such as coronary heart disease, hyperlipidemia, cerebral thrombosis, and prostate cancer caused by high cholesterol have threatened human health. The demand for lipid-lowering products is increasing day by day. Functional red yeast rice products with cholesterol-lowering substance lovastatin as the main ingredient, which are naturally fermented by Monascus, have attracted wide attention. Studies have shown that compared with lovastatin extracted from other fungi or artificially synthesized, lovastatin in red yeast rice products has less crystals, higher solubility, more significant efficacy, and less toxic side effects. With the increasing demand for red yeast rice products in the domestic market and Europe, the United States, and Japan, the development of pure natural fermented functional red yeast rice has obvious social benefits and market prospects.

[0003] The classic raw material for making red yeast rice is rice, and the use of rice to make red yeast rice has a history of more than a thousand years. In addition to rice, millet, wheat, barley, highland barley, oats, buckwheat, sorghum and other grains can be used as raw materials for producing red yeast rice. The reason is that the main component of the above-mentioned grains is starch, and Monascus can secrete amylase to break down starch into sugar, which can then enter the biosynthetic pathways such as glycolysis and tricarboxylic acid cycle for utilization. Lychee kernels are a by-product of lychee processing and are not edible. They are usually disposed of as garbage, which not only wastes resources but also pollutes the environment. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a litchi seed red yeast rice product and a preparation method and application thereof. Compared with ordinary red yeast rice, the red yeast rice product prepared by the method of the present invention not only has higher content of functional ingredients such as lovastatin and red yeast pigment contained in ordinary red yeast rice, thus solving the technical problem of low content of effective ingredients in the red yeast rice product, but also includes active ingredients such as flavonoids and polyphenols originally contained in litchi seed, so that the red yeast rice product has the function of lowering blood lipids and anti-oxidation.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: to provide a method for preparing a litchi seed red yeast rice product, comprising the following steps:

[0006] S1: Inoculate Monascus into liquid seed culture medium under sterile conditions, and culture at 25-35°C for 12-24 hours to obtain Monascus seed liquid with a concentration of 5-10 g / L;

[0007] S2: crushing the litchi kernels to obtain litchi kernel powder with an average particle size of 80-100 μm, then soaking the litchi kernel powder in water for 30-60 min to make the water content of the litchi kernel powder reach 40-80%, and then sterilizing to obtain a culture medium;

[0008] S3: inoculating 10-20wt% of Monascus seed liquid into the culture medium at room temperature, then standing at 30°C for 2-3 days for the first stage of fermentation, and then turning the koji for the first time; then placing the culture medium at 25-30°C for another 21-30 days for the second stage of fermentation to obtain a fermentation product; the interval time for turning the koji in the second stage is 36-60h;

[0009] S4: sterilizing the fermentation product, and then drying it at 50-100° C. for 5-10 hours to obtain a litchi seed red yeast rice product with a water content of ≤10%.

[0010] Studies have shown that the main component of litchi kernel is starch, which accounts for more than 50% of the dry weight of the entire litchi kernel. Therefore, it is feasible to ferment and produce functional red yeast rice using litchi kernel as raw material. In addition, apart from starch, litchi kernel also mainly contains a variety of chemical components such as flavonoids, steroids, tannins, terpenes, polysaccharides, amino acids and pigments. Among them, flavonoid compounds have a variety of pharmacological activities such as lowering blood lipids, anti-inflammatory, anti-oxidation, anti-tumor, anti-virus, anti-liver damage and fibrosis, and have high medicinal value. Unlike cereal starch such as rice, wheat and corn, the content of amylopectin in litchi kernel starch is very high, the content of amylose is low, the particle size of starch granules is small, the particles are densely bound, and it is more difficult to be gelatinized. Therefore, the yield of alcohol produced by fermenting litchi kernel starch with yeast is not high. However, unlike yeast, Monascus itself has the ability to produce amylase and saccharifying enzymes, and the fermentation time of Monascus is generally longer (20-30 days), so litchi kernel starch can be more effectively utilized and converted into other substances. In addition, the red yeast rice fermentation process not only produces amylase and saccharifying enzymes that break down starch, but also produces a variety of enzymes such as protease, lipase, cellulase, etc. The advantage of the combined action of multiple enzymes is that they can effectively destroy the dense structure of the lychee kernel, making it easier to release effective ingredients such as flavonoids, polyphenols, and terpenes in the cells.

[0011] On the basis of the above technical solution, the present invention can also be improved as follows:

[0012] Furthermore, the Monascus fungus is red Monascus or purple Monascus.

[0013] The beneficial effect of adopting the above-mentioned further technical scheme is that Monascus can promote the dissolution of flavonoid compounds because the microorganisms can produce a variety of enzymes such as cellulose hydrolase, pectinase and lignin decomposition enzyme during the fermentation process. These enzymes can effectively degrade the cell wall of litchi kernels, promote the dissolution of flavonoids from inside the cells to outside the cells, and increase the content of flavonoids in the product.

[0014] Further, the components of the liquid seed culture medium in step S1 include 60 g of glucose, 25 g of peptone, 32 g of NaNO, 10 g of corn steep liquor powder, 1 g of MgSO4·7H2O, 1 g of KH2PO4·3H2O and 1000 mL of distilled water.

[0015] Furthermore, the culturing step of Monascus in step S1 is as follows: placing the liquid seed culture medium inoculated with Monascus in a shaking incubator with a rotation speed of 200-250 rpm, and culturing at 30° C. for 18 hours.

[0016] Furthermore, the sterilization temperature in steps S2 and S4 is 121-126° C., and the sterilization time is 20-30 min.

[0017] Furthermore, the water content of the litchi seed powder after soaking in step S2 is 60%.

[0018] Furthermore, the fermentation temperature of the second stage is 28° C. and the fermentation time is 24 days.

[0019] Furthermore, the interval between turning the leaves in the second stage is 48-54h.

[0020] The invention also discloses a litchi seed red yeast rice product, which is prepared by the preparation method.

[0021] The invention also discloses the application of the litchi seed red yeast rice product in the preparation of a blood lipid lowering drug.

[0022] The present invention has the following beneficial effects:

[0023] 1. Traditional red yeast rice products generally use rice as a raw material, and the obtained finished products only contain lovastatin and almost no flavonoids. The present invention uses litchi kernel as a raw material, optimizes fermentation process conditions, and obtains a litchi kernel red yeast rice finished product with a lovastatin content of 4-5.5 mg / g and a total flavonoid content of 2-2.9%, which can effectively increase the contents of lovastatin and flavonoids in the litchi kernel red yeast rice product.

[0024] 2. Litchi kernels are by-products of litchi processing and are generally discarded as garbage, which causes a waste of resources. However, the present invention uses litchi kernels as raw materials to produce functional red yeast rice, which can turn waste into treasure and realize the resource recycling of litchi kernels. This can not only extend the litchi processing industry chain and improve the overall utilization value of litchi, but also reduce resource waste and is beneficial to ecological protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a physical picture of the litchi seed red yeast rice product;

[0026] Figure 2The effect of different initial water contents on the contents of lovastatin and total flavonoids in the product;

[0027] Figure 3 The effect of different inoculation amounts of Monascus seed liquid on the contents of lovastatin and total flavonoids in the product;

[0028] Figure 4 The effects of different fermentation temperatures in the second stage on the contents of lovastatin and total flavonoids in the product;

[0029] Figure 5 The effect of different fermentation time in the second stage on the content of lovastatin and total flavonoids in the product;

[0030] Figure 6 This is the effect of different turning intervals in the second stage on the content of lovastatin and total flavonoids in the product. DETAILED DESCRIPTION

[0031] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific conditions are specified in the embodiments, the process is carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0032] The Monascus used in the following examples and comparative examples were purchased from the China General Microbiological Culture Collection Center (CGMCC), wherein the strain number of the red Monascus is CGMCC3.15746, and the strain number of the purple Monascus is CGMCC3.15548.

[0033] Embodiment 1:

[0034] A method for preparing a litchi seed red yeast rice product comprises the following steps:

[0035] S1: Under sterile conditions, red Monascus was inoculated into a liquid seed culture medium, and then the culture medium was placed in a shaker at a speed of 220 rpm and cultured at 30°C for 18 hours to obtain a Monascus seed liquid with a concentration of 7 g / L; the components of the liquid seed culture medium included 60 g of glucose, 25 g of peptone, 2 g of NaNO3, 10 g of corn steep liquor powder, 1 g of MgSO4·7H2O, 1 g of KH2PO4·3H2O and 1000 mL of distilled water;

[0036] S2: crushing litchi seeds to obtain litchi seed powder with an average particle size of 90 μm, then soaking the litchi seed powder in water for 50 minutes to make the water content of the litchi seed powder reach 60%, and then sterilizing at 123° C. for 25 minutes to obtain a culture medium;

[0037] S3: inoculating 14 wt% of Monascus seed liquid into the culture medium at room temperature, then standing at 30°C for 2 days for the first stage of fermentation, and then turning over the koji for the first time; then placing the culture medium at 28°C for another 24 days for the second stage of fermentation to obtain a fermentation product; the interval time for turning over the koji in the second stage is 48 hours;

[0038] S4: The fermentation product is sterilized at 123°C for 25 minutes, and then dried at 70°C for 8 hours to obtain a litchi seed red yeast rice product with a water content of 8%. Figure 1 The content of lovastatin in the prepared litchi seed red yeast rice product is 5.5 mg / g, and the content of total flavonoids is 2.9%.

[0039] Embodiment 2:

[0040] A method for preparing a litchi seed red yeast rice product comprises the following steps:

[0041] S1: Under sterile conditions, purple Monascus was inoculated into a liquid seed culture medium, and then the culture medium was placed in a shaker at a speed of 200 rpm and cultured at 35°C for 12 hours to obtain a Monascus seed liquid with a concentration of 5 g / L; the components of the liquid seed culture medium included 60 g of glucose, 25 g of peptone, 2 g of NaNO3, 10 g of corn steep liquor powder, 1 g of MgSO4·7H2O, 1 g of KH2PO4·3H2O and 1000 mL of distilled water;

[0042] S2: crushing litchi seeds to obtain litchi seed powder with an average particle size of 100 μm, then soaking in water for 30 minutes to make the water content of the litchi seed powder reach 40%, and then sterilizing at 126° C. for 20 minutes to obtain a culture medium;

[0043] S3: inoculating 10 wt% of Monascus seed liquid into the culture medium at room temperature, then standing at 30°C for 3 days for the first stage of fermentation, and then turning over the koji for the first time; then placing the culture medium at 25°C for another 30 days for the second stage of fermentation to obtain a fermentation product; the interval time for turning over the koji in the second stage is 60 hours;

[0044] S4: sterilizing the fermentation product at 126° C. for 30 min, and then drying at 50° C. for 10 h to obtain a litchi seed red yeast rice product with a moisture content of 6%. The content of lovastatin in the obtained litchi seed red yeast rice product is 4 mg / g, and the content of total flavonoids is 2%.

[0045] Embodiment 3:

[0046] A method for preparing a litchi seed red yeast rice product comprises the following steps:

[0047] S1: Inoculate red Monascus into a liquid seed culture medium under sterile conditions, then place the culture medium in a shaker at a speed of 250 rpm and culture at 25°C for 24 hours to obtain a Monascus seed liquid with a concentration of 10 g / L; the components of the liquid seed culture medium include 60 g of glucose, 25 g of peptone, 2 g of NaNO3, 10 g of corn steep liquor powder, 1 g of MgSO4·7H2O, 1 g of KH2PO4·3H2O and 1000 mL of distilled water;

[0048] S2: crushing litchi seeds to obtain litchi seed powder with an average particle size of 80 μm, then soaking the litchi seed powder in water for 60 minutes to make the water content of the litchi seed powder reach 80%, and then sterilizing at 121° C. for 30 minutes to obtain a culture medium;

[0049] S3: inoculating 20 wt% of Monascus seed liquid into the culture medium at room temperature, then standing at 30°C for 2 days for the first stage of fermentation, and then turning over the koji for the first time; then standing the culture medium at 30°C for another 21 days for the second stage of fermentation to obtain a fermentation product; the interval time for turning over the koji in the second stage is 36 hours;

[0050] S4: sterilizing the fermentation product at 121° C. for 20 min, and then drying at 100° C. for 5 h to obtain a litchi seed red yeast rice product with a moisture content of 10%. The content of lovastatin in the obtained litchi seed red yeast rice product is 4.8 mg / g, and the content of total flavonoids is 2.3%.

[0051] Comparative Example:

[0052] A method for preparing a litchi seed red yeast rice product comprises the following steps:

[0053] S1: Under sterile conditions, red Monascus was inoculated into a liquid seed culture medium, and then the culture medium was placed in a shaker at a speed of 220 rpm and cultured at 30°C for 18 hours to obtain a Monascus seed liquid with a concentration of 7 g / L; the components of the liquid seed culture medium included 60 g of glucose, 25 g of peptone, 2 g of NaNO3, 10 g of corn steep liquor powder, 1 g of MgSO4·7H2O, 1 g of KH2PO4·3H2O and 1000 mL of distilled water;

[0054] S2: crushing litchi seeds to obtain litchi seed powder with an average particle size of 90 μm, then soaking the litchi seed powder in water for 50 minutes to make the water content of the litchi seed powder reach 60%, and then sterilizing at 123° C. for 25 minutes to obtain a culture medium;

[0055] S3: inoculating 14 wt% of Monascus seed liquid into the culture medium at room temperature, then standing at 30°C for 2 days for the first stage of fermentation, and then turning over the koji for the first time; then placing the culture medium at 40°C for another 15 days for the second stage of fermentation to obtain a fermentation product; the interval time for turning over the koji in the second stage is 12 hours;

[0056] S4: sterilizing the fermentation product at 123° C. for 25 min, and then drying at 70° C. for 8 h to obtain a litchi seed red yeast rice product with a moisture content of 15%. The content of lovastatin in the obtained litchi seed red yeast rice product is 3 mg / g, and the content of total flavonoids is 1%.

[0057] Experimental Example 1:

[0058] In order to explore the effect of different initial water contents on the content of lovastatin and total flavonoids in red yeast rice products, 5 groups of experiments were set up. By adjusting the amount of water added and the soaking time in step S2, the water content of litchi kernel powder was adjusted to 50%, 55%, 60%, 70% and 75%, respectively. The other conditions were the same as those in Example 1, and finally 5 groups of litchi kernel red yeast rice products were obtained. The content of lovastatin in red yeast rice products was detected by high performance liquid chromatography (HPLC), and the content of flavonoids was detected by spectrophotometry. The results are as follows: Figure 2 The results showed that with the increase of water content, the contents of flavonoids and lovastatin increased first and then decreased.

[0059] Experimental Example 2:

[0060] In order to explore the effect of different inoculation amounts of Monascus seed liquid on the content of lovastatin and total flavonoids in Monascus products, 6 groups of experiments were set up. The inoculation amount of Monascus seed liquid in step S3 was set to 10%, 12%, 14%, 16%, 18% and 20% respectively. The other conditions were the same as in Example 1, and finally 6 groups of litchi seed Monascus products were obtained. The content of lovastatin in the Monascus products was detected by high performance liquid chromatography (HPLC), and the content of flavonoids was detected by spectrophotometry. The results are as follows: Figure 3 The results showed that with the increase of inoculum size, the yields of flavonoids and lovastatin increased first and then decreased.

[0061] Experimental Example 3:

[0062] In order to study the effect of different fermentation temperatures in the second stage on the content of lovastatin and total flavonoids in red yeast rice products, 6 groups of experiments were set up. The fermentation temperatures in the second stage in step S3 were set to 25°C, 26°C, 27°C, 28°C, 29°C and 30°C respectively. The other conditions were the same as in Example 1. Finally, 6 groups of litchi seed red yeast rice products were obtained. The content of lovastatin in the red yeast rice products was detected by high performance liquid chromatography (HPLC), and the content of flavonoids was detected by spectrophotometry. The results are as follows: Figure 4The results showed that with the increase of fermentation temperature, the yields of flavonoids and lovastatin increased first and then decreased.

[0063] Experimental Example 4:

[0064] In order to explore the effect of different fermentation times in the second stage on the content of lovastatin and total flavonoids in red yeast rice products, 10 groups of experiments were set up. The fermentation time of the second stage in step S3 was set to 3, 6, 9, 12, 15, 18, 21, 24, 27 and 30 days respectively. The other conditions were the same as in Example 1, and finally 10 groups of litchi seed red yeast rice products were obtained. The content of lovastatin in red yeast rice products was detected by high performance liquid chromatography (HPLC), and the content of flavonoids was detected by spectrophotometry. The results are as follows: Figure 5 The results showed that with the increase of fermentation time, the yields of flavonoids and lovastatin increased first and then tended to be flat.

[0065] Experimental Example 5:

[0066] In order to explore the effect of different intervals of turning over the second stage on the content of lovastatin and total flavonoids in red yeast rice products, 5 groups of experiments were set up. The intervals of turning over the second stage in step S3 were set to 36h, 42h, 48h, 54h and 60h respectively. The other conditions were the same as those in Example 1, and finally 5 groups of litchi seed red yeast rice products were obtained. The content of lovastatin in red yeast rice products was detected by high performance liquid chromatography (HPLC), and the content of flavonoids was detected by spectrophotometry. The results are as follows: Figure 6 The results showed that with the increase of the interval between turning over the leaves, the yields of flavonoids and lovastatin increased first and then decreased.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a litchi seed red yeast rice product, characterized in that: The following steps are involved: S1: Inoculate Monascus into liquid seed culture medium under sterile conditions, and culture at 25-35°C for 12-24 hours to obtain Monascus seed liquid with a concentration of 5-10 g / L; S2: crushing the litchi kernels to obtain litchi kernel powder with an average particle size of 80-100 μm, then soaking the litchi kernel powder in water for 30-60 min to make the water content of the litchi kernel powder reach 40-80%, and then sterilizing to obtain a culture medium; S3: inoculating 10-20wt% of Monascus seed liquid into the culture medium at room temperature, then standing at 30°C for 2-3 days for the first stage of fermentation, and then turning the koji for the first time; then placing the culture medium at 25-30°C for another 21-30 days for the second stage of fermentation to obtain a fermentation product; the interval time for turning the koji in the second stage is 36-60h; S4: sterilizing the fermentation product, and then drying it at 50-100° C. for 5-10 hours to obtain a litchi seed red yeast rice product with a water content of ≤10%.

2. The method for preparing the litchi seed red yeast rice product according to claim 1, characterized in that: The monascus fungus is red monascus or purple monascus.

3. The method for preparing the litchi seed red yeast rice product according to claim 1, characterized in that: The components of the liquid seed culture medium in step S1 include 60 g of glucose, 25 g of peptone, 2 g of NaNO3, 10 g of corn steep liquor powder, 1 g of MgSO4·7H2O, 1 g of KH2PO4·3H2O and 1000 mL of distilled water.

4. The method for preparing the litchi seed red yeast rice product according to claim 1, characterized in that: The culturing step of Monascus in step S1 is as follows: placing the liquid seed culture medium inoculated with Monascus in a shaking incubator with a rotation speed of 200-250 rpm, and culturing at 30° C. for 18 hours.

5. The method for preparing the litchi seed red yeast rice product according to claim 1, characterized in that: The sterilization temperature in steps S2 and S4 is 121-126° C., and the sterilization time is 20-30 minutes.

6. The method for preparing the litchi seed red yeast rice product according to claim 1, characterized in that: The water content of the litchi seed powder after soaking in step S2 is 60%.

7. The method for preparing the litchi seed red yeast rice product according to claim 1, characterized in that: The fermentation temperature of the second stage is 28°C and the fermentation time is 24 days.

8. The method for preparing the litchi seed red yeast rice product according to claim 1, characterized in that: The interval between turning over the second stage is 48-54h.

9. The litchi seed red yeast rice product obtained by the preparation method of the litchi seed red yeast rice product according to any one of claims 1 to 8.

10. Use of the litchi seed red yeast rice product according to claim 9 in the preparation of blood lipid lowering drugs.

Images