Method for preparing selenium-enriched yeast

Abstract

The invention relates to the technical field of health-care food, in particular to a method for preparing selenium-enriched yeast. The preparation method comprises the following steps: S1, preparing mixed powder; s2, preparing a paste; s3, standing and fermenting the obtained paste; s4, adding anhydrous alcohol into the obtained fermentation product, stirring, centrifuging, taking precipitate, and recycling supernate; s5, adding purified water into the obtained precipitate, adding silicon dioxide at the same time, performing uniform stirring, and then uniformly laying the mixture on a fluidized bed distribution plate for drying to prepare a dry powder finished product; according to the present invention, the flour is adopted as the carbon source, the bean powder is adopted as the nitrogen source, the simplest solid state fermentation mode is adopted, the fermentation time is short, the selenium-rich yeast can be prepared in a large scale, and the carbon and nitrogen sources are the cheap edible raw materials, and no other chemical components are added, such that the complex separation purification process is not required after the fermentation is completed; the food can be directly eaten only through simple fluidized bed drying, and is low in cost, safe and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of health foods, and specifically to a method for preparing selenium-enriched yeast. Background Art

[0002] Selenium is an essential trace element for the human body. Appropriate intake of selenium can increase the selenium level in the body, increase the activity of glutathione peroxidase in the body, and scavenge free radical particles generated by metabolism in the body. At the same time, it protects cell membranes and their contents from serious damage. Compared with many selenium preparations, selenium-enriched yeast is an ideal selenium supplement for humans and animals. When yeast grows, it absorbs selenium, and the selenium is organically combined with proteins and polysaccharides in the yeast to be converted into biological selenium. It not only retains the original functions of selenium such as improving immunity, scavenging free radicals, and inhibiting tumor cells, but also eliminates the toxic side effects and gastrointestinal irritation of chemical selenium to the human body.

[0003] Currently, the preparation of selenium-enriched yeast mainly still uses the deep liquid fermentation method, that is, selenium-enriched yeast is obtained through enlarged culture, centrifugation, washing, and freeze-drying. Patent CN 103911299 B discloses a selenium-enriched yeast and its preparation method, that is, hydrolyzed sugar is used as a carbon source in a yeast liquid fermentation medium, and amino acids, sodium selenite, and other nutrient elements are additionally added, and cultured for 18 - 25 h to produce selenium-enriched yeast. Patent CN 113999780 B discloses a method for preparing selenium-enriched yeast powder. This method adds a kelp hydrolysate and cultures for 12 - 36 h to prepare selenium-enriched yeast. And patent CN 114214216 B uses the screened yeast, adds nutrients during fermentation and adds a sodium selenite solution in batches, and after liquid fermentation culture for 16 - 48 h, selenium-enriched yeast with a selenium content greater than 7600 μg / g and an organic selenium conversion rate as high as over 93% can be obtained.

[0004] Although the above methods can prepare selenium-enriched yeast on a large scale, the fermentation cycle is long, and it is necessary to gradually enlarge the culture or even supplement the feed, and the nutrient components of the culture medium are relatively complex. Secondly, in order to obtain edible selenium-enriched yeast, the fermentation broth needs to be separated and purified. The process is not only cumbersome, energy-consuming, but also has high requirements for equipment, and the cost of the entire yeast preparation will be relatively high.

[0005] Therefore, there is an urgent need to develop a new method for preparing selenium-enriched yeast to overcome the defects brought by the above traditional methods for preparing selenium-enriched yeast. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing selenium-enriched yeast. By using the simplest solid-state fermentation method, a large amount of selenium-enriched yeast can be prepared in a short fermentation time. At the same time, since both the carbon and nitrogen sources are cheap edible raw materials and no other chemical components are added, after fermentation, it can be directly eaten through simple fluidized bed drying, with low cost, safety, and reliability.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing selenium-enriched yeast, comprising the following steps:

[0009] S1. Place 100 parts of flour and 1 - 20 parts of bean powder in a blender and stir evenly to obtain a mixed powder;

[0010] S2. Dissolve 1 - 20 parts of yeast, 5 - 15 parts of white sugar, 1 - 2 parts of salt, and 0.5 - 5 parts of baking soda in 10 - 25 parts of warm water in advance. After complete dissolution, stir for 5 - 10 min, then add 0.1 - 1 part of selenium-containing compound and stir for 5 - 10 min to obtain a pre-prepared liquid. Pour the prepared pre-prepared liquid into the mixed powder, then add 25 - 40 parts of warm water, turn on the blender and stir for 1 - 4 h to obtain a paste;

[0011] S3. Let the obtained paste stand for fermentation;

[0012] S4. Add anhydrous alcohol to the obtained fermentation product and stir for 1 - 4 h, then centrifuge to take the precipitate, and recycle the supernatant;

[0013] S5. Add purified water to the obtained precipitate to make the solid content 20 - 40%, and at the same time add 0.5 - 1% of silicon dioxide and stir evenly. Then spread it evenly on the boiling bed distribution plate for drying to obtain a dry powder finished product.

[0014] Further, in the step S1, the flour is selected from any one or more of high-gluten flour, medium-gluten flour, and low-gluten flour.

[0015] Further, in the step S1, the bean powder is selected from any one or more of soybean powder, pea powder, and chickpea powder.

[0016] Furthermore, the bean powder is selected from any one or more of soybean cake powder, soybean meal powder, soy protein isolate, soy protein concentrate, soy textured protein, pea protein isolate, and pea protein concentrate.

[0017] Further, in the step S2, the temperature of the warm water is 25 - 40 °C.

[0018] Further, in the step S2, the selenium-containing compound is selected from any one or more of selenium sulfide, sodium selenate, sodium selenite, L-seleno-methylselenocysteine, L-selenomethionine, L-selenocysteine, and selenoglucose.

[0019] Further, in the step S2, the yeast is any one of Saccharomyces cerevisiae, Zygosaccharomyces rouxii, Kluyveromyces marxianus, Pichia pastoris, and Yarrowia lipolytica.

[0020] Further, in the step S3, the temperature of the static fermentation is 25-40 °C, the humidity is 70-80%, and the fermentation time is 1-4 h.

[0021] Further, in the step S4, the added mass of the absolute alcohol is 400% of the mass of the fermentation product.

[0022] Further, in the step S5, the thickness of the laid material layer is 5-15 cm, the inlet air temperature is 60-100 °C, and the air velocity is 0.5-2.5 m / s.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The present invention uses flour as a carbon source and soybean powder as a nitrogen source, abandons the traditional liquid fermentation method of yeast, and adopts the simplest solid fermentation method. It can prepare a large amount of selenium-enriched yeast in only 1-4 h. At the same time, since both the carbon and nitrogen sources are cheap edible raw materials and no other chemical components are added, there is no need for a complex separation and purification process after fermentation, and it can be directly eaten only by simple fluidized bed drying, with low cost, safety and reliability. Specific Embodiments

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] Example 1:

[0027] This example provides a method for preparing selenium-enriched yeast, including the following steps:

[0028] S1. Put 100 parts of flour and 1 part of soybean powder into a blender and stir evenly to prepare a mixed powder.

[0029] Among them, high-gluten flour is selected as the flour.

[0030] Soybean cake powder is selected as the soybean powder.

[0031] S2. Dissolve 1 portion of yeast, 5 portions of white sugar, 1 portion of salt, and 0.5 portion of baking soda in 10 portions of warm water in advance. After complete dissolution, stir for 5 min, then add 0.1 portion of selenium-containing compound and stir for 5 min to prepare a pre-prepared solution. Pour the prepared pre-prepared solution into the mixed powder, then add 25 portions of warm water, and start the blender to stir for 1 h to prepare a paste.

[0032] Among them, the yeast selected is Saccharomyces cerevisiae.

[0033] The selenium-containing compound selected is L-selenocysteine.

[0034] The temperature of the warm water is 25 °C.

[0035] S3. Let the obtained paste stand for fermentation.

[0036] Among them, the temperature for standing fermentation is 25 °C, the humidity is 70%, and the fermentation time is 1 h.

[0037] S4. Add absolute ethanol to the obtained fermentation product and stir for 1 h, then centrifuge to obtain the precipitate, and recycle the supernatant.

[0038] Among them, the added mass of absolute ethanol is 400% of the mass of the fermentation product.

[0039] S5. Add purified water to the obtained precipitate to make the solid content 20%, and at the same time add 0.5% silica, stir evenly, then evenly spread it on the boiling bed distribution plate for drying to prepare a dry powder finished product.

[0040] Among them, the thickness of the laid material layer is 5 cm, the inlet air temperature is 60 °C, and the wind speed is 0.5 m / s.

[0041] Example 2:

[0042] This example provides a method for preparing selenium-enriched yeast, including the following steps:

[0043] S1. Place 100 portions of flour and 10 portions of bean powder in a blender and stir evenly to prepare a mixed powder.

[0044] Among them, the flour selected is high-gluten flour.

[0045] The bean powder selected is pea powder.

[0046] S2. Dissolve 15 portions of yeast, 10 portions of white sugar, 1 portion of salt, and 2 portions of baking soda in 12 portions of warm water in advance. After complete dissolution, stir for 7 min, then add 0.5 portion of selenium-containing compound and stir for 7 min to prepare a pre-prepared solution. Pour the prepared pre-prepared solution into the mixed powder, then add 32 portions of warm water, and start the blender to stir for 2 h to prepare a paste.

[0047] Among them, the yeast selected is Pichia pastoris.

[0048] The selenium-containing compound selected is sodium selenite.

[0049] The temperature of the warm water is 32 °C.

[0050] S3. Leave the obtained paste to ferment.

[0051] Among them, the temperature for static fermentation is 32 °C, the humidity is 75%, and the fermentation time is 2 h.

[0052] S4. Add absolute ethanol to the obtained fermentation product, stir for 2 h, then centrifuge to obtain the precipitate, and recycle the supernatant.

[0053] Among them, the added mass of absolute ethanol is 400% of the mass of the fermentation product.

[0054] S5. Add purified water to the obtained precipitate to make the solid content 30%, and at the same time add 0.7% silica, stir evenly, then spread it evenly on the fluidized bed distributor plate for drying to prepare a dry powder finished product.

[0055] Among them, the thickness of the laid material layer is 10 cm, the inlet air temperature is 80 °C, and the wind speed is 1.5 m / s.

[0056] Example 3:

[0057] This example provides a method for preparing selenium-enriched yeast, including the following steps:

[0058] S1. Place 100 parts of flour and 20 parts of soybean powder in a blender and stir evenly to obtain a mixed powder.

[0059] Among them, the flour selected is high-gluten flour.

[0060] The soybean powder selected is soy protein concentrate powder.

[0061] S2. Dissolve 20 parts of yeast, 15 parts of white sugar, 2 parts of salt, and 5 parts of baking soda in 25 parts of warm water in advance. After complete dissolution, stir for 10 min, then add 1 part of selenium-containing compound and stir for 10 min to obtain a pre-prepared solution. Pour the prepared pre-prepared solution into the mixed powder, and then add 40 parts of warm water, and turn on the blender to stir for 4 h to obtain a paste.

[0062] Among them, the yeast selected is Yarrowia lipolytica.

[0063] The selenium-containing compound selected is L-seleno-methylselenocysteine.

[0064] The temperature of the warm water is 40 °C.

[0065] S3. Leave the obtained paste to ferment.

[0066] Among them, the temperature for static fermentation is 40°C, the humidity is 80%, and the fermentation time is 4 h.

[0067] S4. Add absolute ethanol to the obtained fermentation product, stir for 4 h, then centrifuge to obtain the precipitate, and recycle the supernatant.

[0068] Among them, the added mass of absolute ethanol is 400% of the mass of the fermentation product.

[0069] S5. Add purified water to the obtained precipitate to make the solid content 40%, and at the same time add 1% silica, stir evenly, then spread it evenly on the fluidized bed distributor plate for drying to prepare a dry powder finished product.

[0070] Among them, the thickness of the laid material layer is 15 cm, the inlet air temperature is 100°C, and the wind speed is 2.5 m / s.

[0071] Performance test: Mark the dry powder samples provided in Examples 1 to 3 as Examples 1 to 3 respectively; and conduct the following tests on the relevant performances of the dry powder samples provided in Examples 1 to 3:

[0072] Test for total selenium, inorganic selenium, and organic selenium contents: The test method is to conduct the test according to the standard of GB / T 1903.21-2016 National Food Safety Standard "Food Nutrition Fortifier Selenium-Enriched Yeast", and calculate the proportion of organic selenium.

[0073] The obtained test data are recorded in Table 1 below:

[0074] Table 1 Test results of each group of dry powder finished products

[0075]

[0076]

[0077] By comparing and analyzing the relevant data in Table 1, it can be seen that the dry powder finished product prepared by the present invention meets the national standard requirements. This shows that the method for preparing selenium-enriched yeast provided by the present invention has a broader market prospect and is more suitable for promotion.

[0078] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0079] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for preparing selenium-enriched yeast, characterized in that: The following steps are involved: S1. Place 100 parts of flour and 1 to 20 parts of bean powder in a blender and mix them evenly to prepare a mixed powder; S2, pre-dissolve 1-20 parts of yeast, 5-15 parts of sugar, 1-2 parts of salt, and 0.5-5 parts of baking soda in 10-25 parts of warm water, stir for 5-10 minutes after complete dissolution, then add 0.1-1 parts of selenium-containing compound, and stir for 5-10 minutes to prepare a pre-formulated liquid, pour the prepared pre-formulated liquid into the mixed powder, add 25-40 parts of warm water, start the mixer and stir for 1-4 hours to prepare a paste; S3, allowing the obtained paste to stand and ferment; S4, adding anhydrous alcohol to the obtained fermentation product, stirring for 1 to 4 hours, then centrifuging to obtain the precipitate, and recycling the supernatant; S5. Add purified water to the obtained precipitate to make the solid content 20-40%, add 0.5-1% silicon dioxide at the same time, and stir evenly, then spread it evenly on a fluidized bed distribution plate to dry, and prepare a dry powder product.

2. The method for preparing selenium-enriched yeast according to claim 1, characterized in that: In step S1, the flour is selected from any one or more of high-gluten flour, medium-gluten flour, and low-gluten flour.

3. The method for preparing selenium-enriched yeast according to claim 1, characterized in that: In step S1, the bean flour is selected from any one or more of soybean flour, pea flour and chickpea flour.

4. A method for preparing selenium-enriched yeast according to claim 3, characterized in that: The soybean powder is selected from any one or more of soybean cake powder, soybean meal powder, soybean protein isolate powder, soybean protein concentrate powder, soybean textured protein powder, pea protein isolate powder, and pea protein concentrate powder.

5. The method for preparing selenium-enriched yeast according to claim 1, characterized in that: In step S2, the temperature of the warm water is 25-40°C.

6. The method for preparing selenium-enriched yeast according to claim 1, characterized in that: In step S2, the selenium-containing compound is selected from any one or more of selenium sulfide, sodium selenate, sodium selenite, L-seleno-methylselenocysteine, L-selenomethionine, L-selenocysteine, and selenoglucose.

7. The method for preparing selenium-enriched yeast according to claim 1, characterized in that: In the step S2, the yeast is selected from any one of Saccharomyces cerevisiae, Saccharomyces rouxii, Kluyveromyces marxii, Pichia pastoris, and Yarrowia lipolytica.

8. The method for preparing selenium-enriched yeast according to claim 1, characterized in that: In step S3, the temperature of the static fermentation is 25-40° C., the humidity is 70-80%, and the fermentation time is 1-4 hours.

9. The method for preparing selenium-enriched yeast according to claim 1, characterized in that: In step S4, the added mass of the anhydrous alcohol is 400% of the mass of the fermentation product.

10. The method for preparing selenium-enriched yeast according to claim 1, characterized in that: In the step S5, the thickness of the laid material layer is 5 to 15 cm, the air inlet temperature is 60 to 100° C., and the wind speed is 0.5 to 2.5 m / s.

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