Selenium-rich walnut polypeptide solid beverage and preparation method thereof

Abstract

The invention discloses a selenium-rich walnut polypeptide solid beverage and a preparation method thereof, and belongs to the technical field of food, the preparation method comprises the following specific steps: (1) uniformly mixing walnut powder, rhizoma polygonati powder, sodium selenite and water, and sterilizing to obtain a solid culture material for later use; and (2) inoculating a selenium-resistant strain on the solid culture material, fermenting to obtain walnut selenium polypeptide, and inactivating, drying and crushing the walnut selenium polypeptide to obtain the selenium-rich walnut polypeptide solid beverage. According to the solid beverage prepared by the preparation method disclosed by the invention, selenium elements are combined with walnut protein molecules to form organic selenium polypeptides after participating in metabolism through selenium-resistant strains, and the solid beverage is rich in organic selenium and walnut polypeptides and can be efficiently absorbed and utilized.

Description

Technical Field

[0001] The invention belongs to the field of food technology, and particularly relates to a selenium-enriched walnut polypeptide solid beverage and a preparation method thereof. Background Art

[0002] With rising awareness of healthy eating, the market for plant-based protein beverages is rapidly expanding. Walnut drinks, due to their natural and nutritious properties, are gaining popularity among consumers, particularly in first- and second-tier cities and in the mid- to high-end market. The industry is dominated by traditional brands (such as "Six Walnuts"), while emerging brands are entering the market through differentiated offerings (such as organic, low-sugar, and portable packaging). Furthermore, the entry of cross-border brands (such as dairy companies and beverage giants) is intensifying competition. In the future, the walnut beverage market will face major challenges, including homogeneous competition, fluctuating raw material costs, and consumer sensitivity to additives. Innovations such as sugar-free, functional (such as the addition of probiotics), and environmentally friendly packaging hold great potential.

[0003] Selenium is an essential trace element for the human body and has been listed as one of the 15 essential nutrients. Selenium exists in nature in two forms: organic and inorganic. Inorganic selenium generally refers to sodium selenite and sodium selenate, with a toxic dose of 1500 μg / day. Organic selenium generally exists as selenomethionine, which is metabolized through the methionine metabolic pathway, participates in protein synthesis, and is easily stored and absorbed within tissues. Once absorbed, it is rapidly utilized by the body, effectively improving blood selenium levels. Compared to inorganic selenium, organic selenium is safer, easily absorbed and utilized by the body, and is highly effective in supplementing selenium. Selenoproteins are primarily composed of tansylate and wheatselenium. Research has shown that organic selenium is safe to consume, has no toxic side effects, is non-toxic, has a high absorption and utilization rate, and is highly nutritious.

[0004] Selenium deficiency can cause malfunction of certain vital organs and lead to a variety of serious illnesses. For those with selenium deficiency or low levels, adequate selenium supplementation can not only prevent the development of tumors and liver disease, but also boost immunity, maintain the normal function of vital organs like the heart, liver, lungs, and stomach, and prevent cardiovascular and cerebrovascular diseases in the elderly. Selenium supplementation is necessary throughout life. Animal studies have shown that adequate selenium intake through the diet is essential; failure to do so reduces the body's ability to fight disease. Therefore, a daily intake of selenium is essential, just like the daily intake of nutrients like protein and vitamins. Therefore, selenium supplementation has become a trend in our pursuit of health.

[0005] In the existing technology, biotechnology is used to deeply process walnut protein resources, and then exogenous selenium is added to make walnut milk beverages. However, there is a problem of poor product stability. The use of selenium-resistant bacteria to ferment and prepare polypeptide-selenium chelates converts inorganic selenium into organic selenium bioactive polypeptide-selenium chelates, which significantly improves the absorption rate and utilization rate of selenium.

[0006] Therefore, it is an urgent problem for those skilled in the art to provide a selenium-enriched walnut polypeptide solid beverage and a preparation method thereof. Summary of the Invention

[0007] In order to solve the above problems, the present invention provides a selenium-enriched walnut polypeptide solid beverage and a preparation method thereof.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for preparing a selenium-enriched walnut polypeptide solid beverage comprises the following specific steps:

[0010] (1) walnut powder, polygonatum powder, sodium selenite and water are mixed uniformly and sterilized to obtain a solid culture medium for later use;

[0011] (2) The solid culture medium is inoculated with selenium-resistant bacteria and fermented to obtain walnut selenium polypeptide, and the walnut selenium polypeptide is inactivated, dried and crushed to obtain a selenium-rich walnut polypeptide solid beverage.

[0012] Preferably, the mass ratio of the walnut powder to the polygonatum powder in step (1) is 0.8-1:0-0.2;

[0013] The amount of sodium selenite added is 0.00005-0.002% of the total mass of the walnut powder and the polygonatum powder;

[0014] The amount of water added is 1.5-3 times the total mass of the walnut powder and the polygonatum powder.

[0015] Preferably, the preparation method of the walnut powder in step (1) is: taking walnut kernels, removing oil by low-temperature pressing, so that the residual oil content in the walnut de-oiling residue is 20-40%, and crushing the walnut de-oiling residue to a particle size of 20-100 mesh;

[0016] The preparation method of the polygonatum powder is as follows: crushing sun-dried raw polygonatum to 20-100 meshes.

[0017] Polygonatum sibiricum has the effects of lowering blood pressure, blood sugar, blood lipids, improving immunity and enhancing metabolism. Adding Polygonatum sibiricum to the preparation of walnut solid beverages can enrich the taste and flavor of the product, improve its nutritional value, and is conducive to the cultivation of selenium-resistant bacteria.

[0018] Preferably, the sterilization in step (1) is performed at 121° C. for 20 minutes.

[0019] Preferably, the method for screening selenium-resistant bacteria in step (2) is:

[0020] 1) uniformly mixing walnut powder, polygonatum powder, sodium selenite and water to obtain a liquid culture medium;

[0021] 2) The bacteria are inoculated into liquid culture medium and cultured with shaking. The bacteria with turbid and viscous liquid, mycelium wrapped around and sticky, and good growth are selenium-resistant bacteria.

[0022] Preferably, the mass ratio of the walnut powder, the polygonatum powder, the sodium selenite and the water in step 1) is 0.8-1:0-0.2:5×10 -5 -2×10 -4 :10.

[0023] Preferably, the bacterial species in step 2) is any one or two of Lactobacillus, Bacillus subtilis, Aspergillus niger and Aspergillus oryzae;

[0024] The inoculation amount of the bacterial strain is 0.5-10% of the mass of the liquid culture medium;

[0025] The shaking culture is carried out in a constant temperature shaker at 28-35° C. and a rotation speed of 100-300 rpm for 2-3 days.

[0026] Preferably, when there are two strains of bacteria, the mass ratio between the two is 1:1.

[0027] Preferably, the screening and culturing are repeated 1-3 times to allow the liquid bacteria to adapt to the selenium-rich environment.

[0028] Preferably, the mass volume ratio of the solid culture medium and the selenium-resistant bacteria in step (2) is 200-400 g:5-20 ml.

[0029] Preferably, the fermentation in step (2) is carried out at room temperature, and the fermentation is stopped when turbid mucus appears.

[0030] Preferably, the inactivation in step (2) is carried out at 100° C. for 3 minutes;

[0031] The drying step is drying at 65°C until the moisture content is ≤5.0%;

[0032] The pulverization is performed through a 40-mesh sieve.

[0033] A selenium-rich walnut polypeptide solid beverage is obtained by the preparation method described above.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention provides a selenium-enriched walnut polypeptide solid beverage and a preparation method thereof. The selenium-enriched walnut polypeptide solid beverage is rich in organic selenium and walnut polypeptide and can be efficiently absorbed and utilized;

[0036] (2) The present invention provides a walnut selenium polypeptide solid beverage, wherein the selenium element is metabolized by selenium-tolerant bacteria and then combined with walnut protein molecules to form an organic selenium polypeptide. After multiple tests and screenings, the highest proportion of inorganic selenium added to the fermentation substrate was determined, achieving complete conversion of the selenium element, no inorganic selenium residue, and no side effects;

[0037] (3) The present invention provides a walnut selenium polypeptide solid beverage and a preparation method thereof. The walnut selenium polypeptide solid beverage prepared by the preparation method has a white powder appearance, has no adverse appearance and taste, and is highly accepted by the public;

[0038] (4) The present invention provides a method for preparing a walnut selenium polypeptide solid beverage, which is convenient for large-scale production, has low equipment cost investment, and is easy to convert;

[0039] (5) The walnut selenium polypeptide solid beverage prepared by the present invention is convenient to eat, rich in nutrition, and easy to absorb. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0041] Figure 1 This is a state diagram of the liquid bacterial strain in the selenium-resistant bacterial strain screening in Example 1 of the present invention;

[0042] Figure 2 This is a product picture of the selenium-enriched walnut solid beverage of the present invention. DETAILED DESCRIPTION

[0043] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0044] Example 1

[0045] The present invention provides a method for screening selenium-resistant bacteria, comprising the following specific steps:

[0046] (1) Preparing walnut culture medium: taking walnut kernels, removing oil by low-temperature pressing, making the residual oil content of the walnut residue after degreasing about 20%, crushing the walnut residue after degreasing to a particle size of 100 mesh to obtain walnut powder; crushing three-year-old dried polygonatum to a particle size of 20 mesh to obtain polygonatum powder;

[0047] (2) Preparation of liquid culture medium: Weigh 450 g of walnut powder and 50 g of polygonatum powder, mix the two materials evenly, then weigh 5000 g of water and 0.1 g of sodium selenite, dissolve the sodium selenite in water, add the water to the mixture of walnut powder and polygonatum powder, stir and mix evenly, and divide into 250 mL triangular flasks, 60 mL per bottle, plug half of the bottles with cotton plugs, sterilize at 121 ° C for 20 min, take out and cool to room temperature for use, and do not sterilize the other half for use;

[0048] (3) Inoculation of bacterial powder: Add the following bacterial powder to each bottle of liquid culture medium prepared in step (2): Lactobacillus 0.3g, Bacillus subtilis 0.3g, Aspergillus niger 0.3g, Aspergillus oryzae 0.3g, Lactobacillus 0.15g + Aspergillus niger 0.15g, Bacillus subtilis 0.15g + Aspergillus niger 0.15g, Lactobacillus 0.15g + Aspergillus oryzae 0.15g, Bacillus subtilis 0.15g + Aspergillus oryzae 0.15g and Aspergillus niger 0.15g + Aspergillus oryzae 0.15g, inoculate 9 bottles with each bacterial powder, and inoculate half of the culture medium treated by sterilization and half of the culture medium treated by non-sterilization respectively. Place all the above-mentioned triangular flasks in a constant temperature shaker at 30°C and shake at 150 rpm for 3 days, observe the culture medium in the triangular flasks, select the bacterial liquid that is turbid and viscous, adheres to each other, and grows well as the strain to continue the next step of adaptive culture;

[0049] (4) Repeat steps (2) and (3), wherein the difference in step (2) is that the walnut powder is 400 g and the polygonatum powder is 100 g, and the difference in step (3) is that the inoculation amount per bottle is 5 ml, and the rest are exactly the same, eliminating the samples with poor growth and leaving the strains with good growth, turbid and sticky bacterial liquid, mycelium wrapped around, and sticky to each other. Repeat the screening 3 times to make the liquid strains adapt to the selenium-rich environment and screen out liquid strains with strong adaptability and high conversion rate;

[0050] like Figure 1 This is the screening result of selenium-resistant Lactobacillus strains. The bottle on the left in the figure contains strains that were screened three times in sterile culture medium and grew well after culturing for 3 days, and have strong adaptability. The strain on the right did not grow well after culturing for 3 days and was discarded.

[0051] Example 2

[0052] The present invention provides a method for preparing a selenium-enriched walnut polypeptide solid beverage, comprising the following specific steps:

[0053] (1) Weigh 1000 g of walnut powder, 0.0005 g of sodium selenite, and 2000 g of water. Dissolve the sodium selenite in water first, then add the water containing the sodium selenite to the walnut powder and stir thoroughly to mix well to prepare a walnut solid culture medium. The culture medium is divided into 500 mL culture bottles, 300 g per bottle, sterilized at 121° C. for 20 min, and then taken out and cooled for use.

[0054] (2) The liquid strain of Bacillus subtilis screened in Example 1 was inoculated into the sterilized walnut solid culture medium, 5 mL per bottle was inoculated, and the material was mixed evenly with an inoculation rod. The inoculated culture bottle was placed at room temperature for 3-5 days. When turbid mucus appeared in the bottle, the fermentation was stopped and the walnut selenium polypeptide was inactivated at 100°C for 3 minutes to obtain the inactivated walnut selenium polypeptide. The inactivated walnut selenium polypeptide was dried at 65°C to a moisture content of ≤5.0%, crushed, passed through a 40-mesh sieve, and packaged to obtain a walnut selenium polypeptide solid beverage;

[0055] Sampling was conducted to test the polypeptide content and organic selenium content in the walnut selenium polypeptide drink, among which the polypeptide content was 0.61%, the organic selenium content was 0.5004 mg / kg, the total selenium content was 0.501 mg / kg, and the organic rate was 99.88%.

[0056] Example 3

[0057] The present invention provides a method for preparing a selenium-enriched walnut polypeptide solid beverage, comprising the following specific steps:

[0058] (1) Weigh 900 g of walnut powder and 100 g of polygonatum powder, mix the two, weigh 0.001 g of sodium selenite and 3000 g of water, dissolve the sodium selenite in water, add the water containing the sodium selenite to the walnut powder and polygonatum powder, stir and mix thoroughly to prepare a walnut solid culture medium, and divide the culture medium into 500 mL culture bottles, 300 g per bottle, sterilize at 121° C. for 20 min, take out and cool for use;

[0059] (2) The Lactobacillus + Aspergillus oryzae mixed liquid strain screened in Example 1 was inoculated into sterilized walnut solid culture material, 10 mL per bottle was inoculated, and the material was mixed evenly with an inoculation rod. The inoculated culture bottle was placed at room temperature for 3-5 days. When turbid mucus appeared in the bottle, the fermentation was stopped and the product was inactivated at 100°C for 3 minutes to obtain walnut selenium polypeptide. The inactivated walnut selenium polypeptide was dried at 65°C to a moisture content of ≤5.0%, crushed, passed through a 40-mesh sieve, and packaged to obtain a walnut selenium polypeptide solid beverage (see product). Figure 2 );

[0060] Sampling was performed and ICP-MS was used to detect the polypeptide content and organic selenium content in the walnut selenium polypeptide drink. The polypeptide content was 0.57%, the organic selenium content was 1.038 mg / kg, the total selenium content was 1.064 mg / kg, and the organic rate was 97.56%.

[0061] Example 4

[0062] The present invention provides a method for preparing a selenium-enriched walnut polypeptide solid beverage, comprising the following specific steps:

[0063] (1) Weigh 850 g of walnut powder and 150 g of polygonatum powder, mix the two, weigh 0.002 g of sodium selenite and 1500 g of water, dissolve the sodium selenite in water, add the water containing the dissolved sodium selenite to the walnut powder and polygonatum powder, stir and mix thoroughly, and prepare a walnut solid culture medium. The culture medium is divided into 500 mL culture bottles, 300 g per bottle, sterilized at 121 ° C for 20 min, and taken out and cooled for use;

[0064] (2) The Bacillus subtilis + Aspergillus niger liquid strain screened in the sterilized liquid culture medium of Example 1 was inoculated into the sterilized walnut solid culture medium, 15 mL per bottle was inoculated, and the material was mixed evenly with an inoculation rod. The inoculated culture bottle was placed at room temperature for 3-5 days. When turbid mucus appeared in the bottle, the fermentation was stopped and the walnut selenium polypeptide was inactivated at 100°C for 3 minutes to obtain the inactivated walnut selenium polypeptide. The inactivated walnut selenium polypeptide was dried at 65°C to a moisture content of ≤5.0%, crushed, passed through a 40-mesh sieve, and packaged to obtain a walnut selenium polypeptide solid beverage;

[0065] Sampling was performed and ICP-MS was used to detect the polypeptide content and organic selenium content in the walnut selenium polypeptide drink. The polypeptide content was 0.54%, the organic selenium content was 1.967 mg / kg, the total selenium content was 2.0016 mg / kg, and the organic rate was 98.27%.

[0066] Example 5

[0067] The present invention provides a method for preparing a selenium-enriched walnut polypeptide solid beverage, comprising the following specific steps:

[0068] (1) Weigh 850 g of walnut powder and 150 g of polygonatum powder, mix the two, weigh 0.002 g of sodium selenite and 1500 g of water, dissolve the sodium selenite in water, add the water containing the dissolved sodium selenite to the walnut powder and polygonatum powder, stir and mix thoroughly, and prepare a walnut solid culture medium. The culture medium is divided into 500 mL culture bottles, 300 g per bottle, sterilized at 121 ° C for 20 min, and taken out and cooled for use;

[0069] (2) The Bacillus subtilis + Aspergillus niger liquid strain screened in the non-sterile liquid culture medium of Example 1 was inoculated into the sterilized walnut solid culture medium, 15 mL per bottle was inoculated, and the material was mixed evenly with an inoculation rod. The inoculated culture bottle was placed at room temperature for 3-5 days. When turbid mucus appeared in the bottle, the fermentation was stopped and the walnut selenium polypeptide was inactivated at 100°C for 3 minutes to obtain the inactivated walnut selenium polypeptide. The inactivated walnut selenium polypeptide was dried at 65°C to a moisture content of ≤5.0%, crushed, passed through a 40-mesh sieve, and packaged to obtain a walnut selenium polypeptide solid beverage;

[0070] Sampling was performed and ICP-MS was used to detect the polypeptide content and organic selenium content in the walnut selenium polypeptide drink. The polypeptide content was 0.52%, the organic selenium content was 2.0017 mg / kg, the total selenium content was 2.0110 mg / kg, and the organic rate was 99.54%.

[0071] The various embodiments are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to in detail.

[0072] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a selenium-enriched walnut polypeptide solid beverage, characterized in that: The specific steps include: (1) walnut powder, polygonatum powder, sodium selenite and water are mixed uniformly and sterilized to obtain a solid culture medium for later use; (2) The solid culture medium is inoculated with selenium-resistant bacteria and fermented to obtain walnut selenium polypeptide, and the walnut selenium polypeptide is inactivated, dried and crushed to obtain a selenium-rich walnut polypeptide solid beverage.

2. The method for preparing a selenium-enriched walnut polypeptide solid beverage according to claim 1, wherein The mass ratio of the walnut powder to the polygonatum powder in step (1) is 0.8-1:0-0.2; The amount of sodium selenite added is 0.00005-0.002% of the total mass of the walnut powder and the polygonatum powder; The amount of water added is 1.5-3 times the total mass of the walnut powder and the polygonatum powder.

3. The method for preparing a selenium-enriched walnut polypeptide solid beverage according to claim 1, wherein: The preparation method of the walnut powder in step (1) is as follows: taking walnut kernels, removing oil by low-temperature pressing, so that the residual oil content in the walnut de-oiling residue is 20-40%, and crushing the walnut de-oiling residue to a particle size of 20-100 mesh; The preparation method of the polygonatum powder is as follows: crushing sun-dried raw polygonatum to 20-100 meshes.

4. The method for preparing a selenium-enriched walnut polypeptide solid beverage according to claim 1, wherein The screening method for selenium-resistant bacteria in step (2) is: 1) uniformly mixing walnut powder, polygonatum powder, sodium selenite and water to obtain a liquid culture medium; 2) The bacteria are inoculated into liquid culture medium and cultured with shaking. The bacteria with turbid and viscous liquid, mycelium wrapped around and sticky, and good growth are selenium-resistant bacteria.

5. The method for preparing a selenium-enriched walnut polypeptide solid beverage according to claim 4, characterized in that: The mass ratio of the walnut powder, the polygonatum powder, the sodium selenite and the water in step 1) is 0.8-1:0-0.2:5×10 -5 -2×10 -4 :

10.

6. The method for preparing a selenium-enriched walnut polypeptide solid beverage according to claim 4, characterized in that: In step 2), the bacterial species are any one or two of Lactobacillus, Bacillus subtilis, Aspergillus niger and Aspergillus oryzae; The inoculation amount of the bacterial strain is 0.5-10% of the mass of the liquid culture medium; The shaking culture is carried out in a constant temperature shaker at 28-35° C. and a rotation speed of 100-300 rpm for 2-3 days.

7. The method for preparing a selenium-enriched walnut polypeptide solid beverage according to claim 1, characterized in that: The mass volume ratio of the solid culture medium and the selenium-resistant bacteria in step (2) is 200-400 g:5-20 ml.

8. The method for preparing a selenium-enriched walnut polypeptide solid beverage according to claim 1, characterized in that: The fermentation in step (2) is carried out at room temperature, and the fermentation is stopped when turbid mucus appears.

9. The method for preparing a selenium-enriched walnut polypeptide solid beverage according to claim 1, characterized in that: The inactivation in step (2) is carried out at 100° C. for 3 minutes; The drying step is drying at 65°C until the moisture content is ≤5.0%; The pulverization is performed through a 40-mesh sieve.

10. A selenium-enriched walnut polypeptide solid beverage obtained by the preparation method according to any one of claims 1 to 9.

Images