A foam-stable Polygonatum beer and its preparation method

Abstract

This invention provides a foam-stable Polygonatum beer and its preparation method. The method includes the following steps: preparing Polygonatum polysaccharide and Polygonatum protease hydrolysate; preparing Polygonatum polysaccharide grafted with Australian malt protein; pulverizing malt; saccharifying until complete, filtering to obtain wort; boiling the wort, adding hops, and then subjecting the mixture to vortex sedimentation; cooling, adding Polygonatum protease hydrolysate, and filling the fermentation tank from the bottom for fermentation; cooling again, adding Polygonatum polysaccharide grafted with Australian malt protein, and performing post-fermentation; collecting the uppermost layer of liquid from the membrane to obtain the foam-stable Polygonatum beer. This invention utilizes Polygonatum protease hydrolysate in conjunction with Polygonatum polysaccharide grafted with Australian malt protein to improve the foaming power and foam retention of Polygonatum beer. The small molecule peptides of Polygonatum protease hydrolysate can quickly enter the gas-liquid interface, expand, and reorganize the interface, enhancing foaming properties; simultaneously, hydrophobic amino acid residues cross-link with iso-α-acids, reducing the surface tension of the beer foam, ultimately promoting beer foam stability.

Description

Technical Field

[0001] This invention relates to the technical field of alcoholic beverage processing, specifically to a foam-stable Polygonatum beer and its preparation method. Background Technology

[0002] Beer is one of the oldest alcoholic beverages and ranks third in global consumption after water and tea. Made primarily from barley malt, hops, and water through yeast fermentation, beer is a low-alcohol beverage rich in carbon dioxide, often called "liquid bread." The quality of beer foam refers to a series of intrinsically related characteristics, including foam quantity, stability, adhesion to the walls, concentration, viscosity, and strength. Among these, foam stability, as a key comprehensive characteristic, is often used as a crucial indicator in beer foam quality research; therefore, the stability of beer foam is an important aspect of beer research.

[0003] Polygonatum is the dried rhizome of several perennial herbaceous plants, including Polygonatum sibiricum, Polygonatum multiflorum, and Polygonatum yunnanense, belonging to the genus Polygonatum in the Liliaceae family. In my country, Polygonatum has been used medicinally for over 2000 years and is currently one of the most sought-after medicinal materials. Polygonatum is sweet in taste and neutral in nature, entering the spleen, lung, and kidney meridians. It has functions such as tonifying qi and nourishing yin, strengthening the spleen, moistening the lungs, and benefiting the kidneys. Modern pharmacological studies have shown that Polygonatum can enhance immunity, lower blood sugar, lower blood lipids, and has antibacterial, anti-inflammatory, and antioxidant effects. Currently, the most common way to add it to beer is to directly add it after crushing it. However, this does not maximize its effects. Generally, Polygonatum polysaccharides and Polygonatum protein are among the most common and effective components of Polygonatum. How to maximize its effects in beer is a topic of our current research. Summary of the Invention

[0004] Technical Problem to be Solved: To address the aforementioned technical problems, the purpose of this invention is to provide a foam-stable Polygonatum beer and its preparation method. This invention utilizes Polygonatum protease hydrolysate synergistically grafted with Polygonatum polysaccharide onto Australian malt protein to improve the foaming power and foam retention of Polygonatum beer. During enzymatic hydrolysis, Polygonatum protein forms a large number of soluble small molecule peptides. These small molecule peptides can quickly enter the gas-liquid interface, expand, and reorganize the interface, thus enhancing foaming performance. Simultaneously, some hydrophobic amino acid residues originally embedded within the protein molecules are exposed. Furthermore, the iso-α-acids produced during wort fermentation can cross-link with amino acid residues of different hydrophobicities through hydrophobic bonds, thereby reducing the surface tension of the beer foam and ultimately promoting foam stability. On the other hand, by adding Polygonatum polysaccharide grafted onto Australian malt protein, Polygonatum polysaccharide is grafted onto the active side chain groups of Australian malt protein, such as -NH2 and -OH, via the Maillard reaction. The steric hindrance provided by Polygonatum polysaccharide increases the thickness of the interfacial film formed at the gas-water interface, further improving foam stability.

[0005] Technical solution: A method for preparing foam-stable Polygonatum beer, comprising the following steps:

[0006] S1: Take the dried rhizome of Polygonatum, clean it thoroughly, mix it with 20% rice wine, place it in a steamer, steam it for 3 hours, take it out and bake it until it is half-dry, dry it at a constant temperature, and grind it into 80 mesh.

[0007] S2: Add 25 times the volume of water and stir. Place in a microwave oven and extract for 50-70 seconds at a microwave intensity of 0.95W / g. After extraction, centrifuge to obtain Polygonatum residue and filtrate.

[0008] S3: Add Savage reagent to the filtrate, filter and take the supernatant, concentrate the supernatant, add anhydrous ethanol to the concentration to 80%, let stand at 4℃ for 24h, centrifuge at 4000r / min for 6-8min, wash the precipitate and dry to obtain Polygonatum polysaccharide.

[0009] S4: Take the residue of Polygonatum sibiricum, add 0.2 mol / L phosphate buffer, stir for 4 h, centrifuge at 10000 r / min for 15 min, take the supernatant, add ammonium sulfate until the solution is saturated, let stand at 4℃, centrifuge to take the precipitate and put it into a 3500 Da dialysis bag for dialyzing to obtain Polygonatum sibiricum protein solution, freeze dry to obtain Polygonatum sibiricum protein;

[0010] S5: Prepare a 7% concentration of polygonatum protein solution, adjust the pH to 8.0, and set the temperature to 45℃. Add trypsin and maintain the pH of the system at 8.0 by adding 0.5 mol / L NaOH solution dropwise. After reacting for 20-30 min, remove the enzymatic hydrolysate, inactivate the enzyme by boiling in a water bath for 10 min, cool to room temperature, adjust the pH to 7.0, centrifuge at 3000 r / min for 20 min, and freeze-dry the supernatant to obtain polygonatum protein hydrolysate.

[0011] S6: Take malt and crush it to a particle size ≤0.03mm using the re-moistening crushing method to obtain malt granules;

[0012] S7: Mix malt granules and water at a mass ratio of 1:5, and saccharify at a temperature of 66-68℃ until saccharification is complete, then filter to obtain wort.

[0013] S8: Boil the wort for 70 minutes. Add hops at 40 minutes and 65 minutes after the wort starts boiling. After boiling, allow the wort to swirl and settle.

[0014] S9: Cool the wort obtained by vortex sedimentation to 18-20℃, add the protease hydrolysate of Polygonatum sibiricum, and fill it into the fermentation tank from the bottom. The fermentation tank is lined with multiple layers of mesh, and beer-specific yeast is fixed on the mesh. Ferment for 8-10 days.

[0015] S10: Cool to 4-6℃, add Polygonatum polysaccharide grafted with Australian wheat protein, and carry out post-fermentation for 18-20 days. Take the liquid from the uppermost layer of the membrane to obtain Polygonatum beer with stable foam.

[0016] Furthermore, the mass-to-volume ratio of the Polygonatum sibiricum filter residue to the phosphate buffer in S4 is 1 g:(30-35) mL.

[0017] Furthermore, the mass ratio of trypsin to protamine in S5 is 1.5:100.

[0018] Furthermore, the conditions for the rehydration and pulverization method in S6 are: 1% water content, 40°C temperature, and 1 hour time.

[0019] Furthermore, the amount of Polygonatum hydrolysate added in S9 is 0.5-2% of the wort mass.

[0020] Furthermore, the spacing between the multiple layers of mesh in S9 is 20-30cm.

[0021] Furthermore, the preparation method of the membrane in S9 is as follows:

[0022] (1) Disperse the aluminum silicate fiber evenly in the silica sol, slowly add 15% ammonium chloride solution, and stir;

[0023] (2) Add nano garnet powder and stir quickly until evenly mixed;

[0024] (3) Transfer to the syringe of the electrospinning device for electrospinning to obtain an electrospinning web;

[0025] (4) After the electrospun web has gelled and hardened, remove it from the receiving plate, dry it, and obtain a web with a pore size of 2-5 μm.

[0026] (5) Soak the mesh in water, rinse it, and then put it in an oven for dry heat sterilization at 200℃ to obtain sterilized mesh;

[0027] (6) Prepare a yeast cell content of 2×10 8 A suspension of beer-specific yeast cells per mL was used to adsorb yeast cells onto a sterile mesh at 15°C for 30-40 min, and then the mesh was continuously cultured in a reactor at the same temperature for 2 h to obtain a mesh with beer-specific yeast cells immobilized.

[0028] Furthermore, the mass ratio of the aluminum silicate fiber, silica sol, ammonium chloride, and nano garnet powder is 0.4:100:7:270.

[0029] Furthermore, the preparation method of the Polygonatum polysaccharide grafted with Australian wheat protein in S10 is as follows:

[0030] (1) Take the Polygonatum polysaccharide and Australian wheat protein obtained from S3, prepare Polygonatum polysaccharide solution and Australian wheat protein solution with a mass fraction of 1% respectively, mix the two in a volume ratio of 1:(1-2) and stir evenly.

[0031] (2) After vacuum freeze-drying, a mixture of Polygonatum polysaccharide was obtained. The mixture was placed in a desiccator with a saturated potassium bromide solution at the bottom and reacted at 85°C for 2 hours.

[0032] (3) Dissolve in deionized water, dialyze for 48 hours and freeze dry to obtain Polygonatum polysaccharide grafted Australian wheat protein.

[0033] The foam-stable Polygonatum beer prepared by the above preparation method.

[0034] Beneficial effects:

[0035] 1. This invention utilizes Polygonatum sibiricum enzymatic hydrolysate and Polygonatum sibiricum polysaccharide grafted onto Australian wheat protein to improve the foaming power and foam retention of Polygonatum sibiricum beer. During enzymatic hydrolysis, Polygonatum sibiricum protein forms a large number of soluble small molecule peptides. These small molecule peptides can quickly enter the gas-liquid interface, expand, and reorganize the interface, thus enhancing foaming power. At the same time, some hydrophobic amino acid residues that were originally embedded inside the protein molecules are also exposed. The iso-α-acids produced during wort fermentation can cross-link with amino acid residues of different hydrophobicities through hydrophobic bonds, thereby reducing the surface tension of beer foam and ultimately promoting the stability of beer foam. On the other hand, by adding Polygonatum sibiricum polysaccharide grafted onto Australian wheat protein, Polygonatum sibiricum polysaccharide is grafted onto the active groups of the Australian wheat protein side chain, such as -NH2 and -OH, through Maillard reaction. The steric hindrance provided by Polygonatum sibiricum polysaccharide can increase the thickness of the interfacial film formed at the gas-water interface, thereby further improving foam stability.

[0036] 2. The present invention has a multi-layer mesh with beer-specific yeast fixed in place. First, the yeast can be reused after fixation, saving resources. Second, it can reduce the production of proteinase A, which is one of the main causes of foam instability. This application reduces it from the source. Finally, the mesh pore size of the present application is 2-5μm, which can effectively clarify the beer and improve its appearance. It can also further screen out proteinase A and reduce its impact on the beer.

[0037] 3. The addition of Polygonatum protease hydrolysate and Polygonatum polysaccharide grafted Australian wheat protein in this invention not only greatly helps foam stability, but also increases the antioxidant effect of beer, and gives it a rich and unique taste, with nourishing and health-preserving effects. Detailed Implementation

[0038] This invention proposes a foam-stable Polygonatum beer and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following will provide a more detailed description of the invention with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0039] Example 1

[0040] Preparation of Polygonatum polysaccharide and Polygonatum protease hydrolysate:

[0041] S1: Take the dried rhizome of Polygonatum, clean it thoroughly, mix it with 20% rice wine, place it in a steamer, steam it for 3 hours, take it out and bake it until it is half-dry, dry it at a constant temperature, and grind it into 80 mesh.

[0042] S2: Add 25 times the volume of water and stir. Place in a microwave oven and extract for 70 seconds at a microwave intensity of 0.95 W / g. After extraction, centrifuge to obtain Polygonatum residue and filtrate.

[0043] S3: Add Savage reagent to the filtrate, filter and take the supernatant, concentrate the supernatant, add anhydrous ethanol to the concentration to 80%, let stand at 4℃ for 24h, centrifuge at 4000r / min for 6-8min, wash the precipitate and dry to obtain Polygonatum polysaccharide.

[0044] S4: Take the Polygonatum sibiricum filter residue, add 0.2 mol / L phosphate buffer, the mass-volume ratio of Polygonatum sibiricum filter residue to phosphate buffer is 1 g: 35 mL, stir for 4 h, centrifuge at 10000 r / min for 15 min, take the supernatant, add ammonium sulfate until the solution is saturated, let stand at 4℃, centrifuge to take the precipitate and put it into a 3500 Da dialysis bag for dialyzing to obtain Polygonatum sibiricum protein solution, freeze dry to obtain Polygonatum sibiricum protein;

[0045] S5: Prepare a 7% solution of polygonatum protein, adjust the pH to 8.0, and set the temperature to 45℃. Add trypsin at a mass ratio of 1.5:100 to trypsin. Maintain the pH of the system at 8.0 by adding 0.5 mol / L NaOH solution dropwise. After reacting for 20-30 min, remove the enzymatic hydrolysate, inactivate the enzyme by boiling in a water bath for 10 min, cool to room temperature, adjust the pH to 7.0, centrifuge at 3000 r / min for 20 min, and freeze-dry the supernatant to obtain polygonatum protein hydrolysate.

[0046] Dissolve the protein hydrolysate of Polygonatum sibiricum in 0.01 mol / L, pH 4.5 acetate buffer solution to prepare a 2% solution. Stir at 7000 r / min for 1 min in a high-speed tissue homogenizer. Quickly pour the solution into a graduated cylinder and record the initial foam height H0 (cm) and the final height H1 (cm) after 60 min. Calculate the foaming properties and bubble stability according to the following formula.

[0047]

[0048]

[0049] Results: Foaming power was 234.6%, and foam stability was 86.4%.

[0050] Example 2

[0051] The preparation method of grafting Australian wheat protein with Polygonatum polysaccharide is as follows:

[0052] (1) Take the Polygonatum polysaccharide and Australian wheat protein obtained from S3, prepare Polygonatum polysaccharide solution and Australian wheat protein solution with a mass fraction of 1% respectively, mix the two in a volume ratio of 1:1 and stir evenly.

[0053] (2) After vacuum freeze-drying, a mixture of Polygonatum polysaccharide was obtained. The mixture was placed in a desiccator with a saturated potassium bromide solution at the bottom and reacted at 85°C for 2 hours.

[0054] (3) Dissolve in deionized water, dialyze for 48 hours and freeze dry to obtain Polygonatum polysaccharide grafted Australian wheat protein.

[0055] Example 3

[0056] The preparation method of grafting Australian wheat protein with Polygonatum polysaccharide is as follows:

[0057] (1) Take the Polygonatum polysaccharide and Australian wheat protein obtained from S3, and prepare Polygonatum polysaccharide solution and Australian wheat protein solution with a mass fraction of 1% respectively. Mix the two in a volume ratio of 1:1.5 and stir evenly.

[0058] (2) After vacuum freeze-drying, a mixture of Polygonatum polysaccharide was obtained. The mixture was placed in a desiccator with a saturated potassium bromide solution at the bottom and reacted at 85°C for 2 hours.

[0059] (3) Dissolve in deionized water, dialyze for 48 hours and freeze dry to obtain Polygonatum polysaccharide grafted Australian wheat protein.

[0060] Example 4

[0061] The preparation method of grafting Australian wheat protein with Polygonatum polysaccharide is as follows:

[0062] (1) Take the Polygonatum polysaccharide and Australian wheat protein obtained from S3, prepare Polygonatum polysaccharide solution and Australian wheat protein solution with a mass fraction of 1% respectively, mix the two in a volume ratio of 1:2 and stir evenly;

[0063] (2) After vacuum freeze-drying, a mixture of Polygonatum polysaccharide was obtained. The mixture was placed in a desiccator with a saturated potassium bromide solution at the bottom and reacted at 85°C for 2 hours.

[0064] (3) Dissolve in deionized water, dialyze for 48 hours and freeze dry to obtain Polygonatum polysaccharide grafted Australian wheat protein.

[0065] Dissolve the polysaccharide grafted with Australian wheat protein in deionized water to prepare a 1% (w / w) solution. Mix the solution in a high-speed tissue homogenizer at 6500 rpm for 5 min. Quickly pour the solution into a graduated cylinder and record the initial foam height H0 (cm) and the final height H1 (cm) after 60 min. Calculate the foaming properties and bubble stability using the following formula.

[0066]

[0067]

[0068] Antioxidant activity assay: Prepare 0.2 mL of 4.0 mg / mL Polygonatum polysaccharide-grafted Australian wheat protein solution, add 7.8 mL of 1.0 × 10⁻⁶ oz solution. -4Mix the mol / L DPPH radical solution thoroughly, measure the absorbance at 515 nm, and calculate the DPPH radical scavenging rate.

[0069] DPPH free radical scavenging rate = [1-Ai / AO]×100%; where Ai is the absorbance of the sample with DPPH solution and AO is the absorbance of the blank solution with DPPH solution.

[0070] Table 1

[0071] Foaming power (%) Foam stability (%) DPPH free radical scavenging rate (%) Example 2 99.0 98.3 98.7 Example 3 99.2 97.5 98.5 Example 4 99.6 96.9 98.4

[0072] As can be seen from Table 1, Example 2 had the worst foaming power, but the best foam stability and antioxidant properties. Example 4 had the best foaming power, but the worst foam stability and antioxidant properties. The performance of Example 3 was in the middle range. Taking all factors into consideration, the Polygonatum polysaccharide grafted with Australian wheat protein prepared in Example 3 was selected for subsequent experiments.

[0073] Example 5

[0074] The preparation method of the membrane is as follows, by weight:

[0075] (1) Disperse 0.4 parts of aluminum silicate fiber evenly in 100 parts of silica sol, slowly add 7 parts of 15% ammonium chloride solution, and stir;

[0076] (2) Add 270 parts of nano garnet powder and stir quickly until evenly mixed;

[0077] (3) Transfer to the syringe of the electrospinning device for electrospinning to obtain an electrospinning web;

[0078] (4) After the electrospun web has gelled and hardened, remove it from the receiving plate, dry it, and obtain a web with a pore size of 2-5 μm.

[0079] (5) Soak the mesh in water, rinse it, and then put it in an oven for dry heat sterilization at 200℃ to obtain sterilized mesh;

[0080] (6) Prepare a yeast cell content of 2×10 8 A suspension of beer-specific yeast cells per mL was used to adsorb yeast cells onto a sterile mesh membrane at 15°C for 40 min, followed by continuous incubation at the same temperature in a reactor for 2 h to obtain a mesh membrane immobilized with beer-specific yeast. The beer-specific yeast loading was determined to be 7.8 × 10⁻⁶ cells / mL. 6 pcs / g mesh

[0081] Example 6

[0082] A method for preparing foam-stable Polygonatum beer includes the following steps:

[0083] S1: Take malt and crush it to a particle size ≤0.03mm using the re-moistening crushing method. The conditions for the re-moistening crushing method are: 1% water content, temperature 40℃, and time 1h to obtain malt granules.

[0084] S2: Mix malt granules and water at a mass ratio of 1:5, and saccharify at 66°C until saccharification is complete. Filter to obtain wort.

[0085] S3: Boil the wort for 70 minutes. Add hops at 40 minutes and 65 minutes after the wort starts boiling. After boiling, allow the wort to swirl and settle.

[0086] S4: Cool the wort obtained by vortex sedimentation to 18°C, add Polygonatum hydrolysate at a rate of 0.5% of the wort mass, fill it into the fermentation tank from the bottom, the fermentation tank is lined with multiple layers of mesh film with a spacing of 20cm between the layers of mesh film, beer-specific yeast is fixed on the mesh film, and ferment for 8 days.

[0087] S5: Cool to 4℃, add Polygonatum polysaccharide grafted with Australian wheat protein, and carry out post-fermentation for 18 days. Take the liquid from the uppermost layer of the membrane to obtain Polygonatum beer with stable foam.

[0088] Example 7

[0089] A method for preparing foam-stable Polygonatum beer includes the following steps:

[0090] S1: Take malt and crush it to a particle size ≤0.03mm using the re-moistening crushing method. The conditions for the re-moistening crushing method are: 1% water content, temperature 40℃, and time 1h to obtain malt granules.

[0091] S2: Mix malt granules and water at a mass ratio of 1:5, and saccharify at 67°C until saccharification is complete. Filter to obtain wort.

[0092] S3: Boil the wort for 70 minutes. Add hops at 40 minutes and 65 minutes after the wort starts boiling. After boiling, allow the wort to swirl and settle.

[0093] S4: Cool the wort obtained by vortex sedimentation to 19°C, add Polygonatum hydrolysate, the amount of Polygonatum hydrolysate added is 1.0% of the wort mass, fill it from the bottom into the fermentation tank, the fermentation tank is lined with multiple layers of mesh film, the spacing between the multiple layers of mesh film is 25cm, beer-specific yeast is fixed on the mesh film, ferment for 9 days;

[0094] S5: Cool to 5℃, add Polygonatum polysaccharide grafted with Australian wheat protein, and carry out post-fermentation for 19 days. Take the liquid from the uppermost layer of the membrane to obtain Polygonatum beer with stable foam.

[0095] Example 8

[0096] A method for preparing foam-stable Polygonatum beer includes the following steps:

[0097] S1: Take malt and crush it to a particle size ≤0.03mm using the re-moistening crushing method. The conditions for the re-moistening crushing method are: 1% water content, temperature 40℃, and time 1h to obtain malt granules.

[0098] S2: Mix malt granules and water at a mass ratio of 1:5, and saccharify at 67°C until saccharification is complete. Filter to obtain wort.

[0099] S3: Boil the wort for 70 minutes. Add hops at 40 minutes and 65 minutes after the wort starts boiling. After boiling, allow the wort to swirl and settle.

[0100] S4: Cool the wort obtained by vortex sedimentation to 19°C, add Polygonatum hydrolysate at a rate of 1.5% of the wort mass, fill it into the fermentation tank from the bottom, the fermentation tank is lined with multiple layers of mesh film with a spacing of 25cm between the layers of mesh film, beer-specific yeast is fixed on the mesh film, and ferment for 9 days.

[0101] S5: Cool to 5℃, add Polygonatum polysaccharide grafted with Australian wheat protein, and carry out post-fermentation for 19 days. Take the liquid from the uppermost layer of the membrane to obtain Polygonatum beer with stable foam.

[0102] Example 9

[0103] A method for preparing foam-stable Polygonatum beer includes the following steps:

[0104] S1: Take malt and crush it to a particle size ≤0.03mm using the re-moistening crushing method. The conditions for the re-moistening crushing method are: 1% water content, temperature 40℃, and time 1h to obtain malt granules.

[0105] S2: Mix malt granules and water at a mass ratio of 1:5, and saccharify at 67°C until saccharification is complete. Filter to obtain wort.

[0106] S3: Boil the wort for 70 minutes. Add hops at 40 minutes and 65 minutes after the wort starts boiling. After boiling, allow the wort to swirl and settle.

[0107] S4: Cool the wort obtained by vortex sedimentation to 19°C, add Polygonatum hydrolysate at a rate of 1.5% of the wort mass, fill it into the fermentation tank from the bottom, the fermentation tank is lined with multiple layers of mesh film with a spacing of 30cm between the layers of mesh film, beer-specific yeast is fixed on the mesh film, and ferment for 9 days.

[0108] S5: Cool to 5℃, add Polygonatum polysaccharide grafted with Australian wheat protein, and carry out post-fermentation for 19 days. Take the liquid from the uppermost layer of the membrane to obtain Polygonatum beer with stable foam.

[0109] Example 10

[0110] A method for preparing foam-stable Polygonatum beer includes the following steps:

[0111] S1: Take malt and crush it to a particle size ≤0.03mm using the re-moistening crushing method. The conditions for the re-moistening crushing method are: 1% water content, temperature 40℃, and time 1h to obtain malt granules.

[0112] S2: Mix malt granules and water at a mass ratio of 1:5, and saccharify at 68°C until saccharification is complete. Filter to obtain wort.

[0113] S3: Boil the wort for 70 minutes. Add hops at 40 minutes and 65 minutes after the wort starts boiling. After boiling, allow the wort to swirl and settle.

[0114] S4: Cool the wort obtained by vortex sedimentation to 20°C, add Polygonatum hydrolysate at 2% of the wort mass, fill it into the fermentation tank from the bottom, the fermentation tank is lined with multiple layers of mesh with a spacing of 30cm between the layers of mesh, beer yeast is fixed on the mesh, and fermentation is carried out for 10 days.

[0115] S5: Cool to 6℃, add Polygonatum polysaccharide grafted with Australian wheat protein, and carry out post-fermentation for 20 days. Take the liquid from the uppermost layer of the membrane to obtain Polygonatum beer with stable foam.

[0116] Comparative Example 1

[0117] The difference between this comparative example and Example 8 is that no Polygonatum sibiricum protein hydrolysate was added, as detailed below:

[0118] A method for preparing foam-stable Polygonatum beer includes the following steps:

[0119] S1: Take malt and crush it to a particle size ≤0.03mm using the re-moistening crushing method. The conditions for the re-moistening crushing method are: 1% water content, temperature 40℃, and time 1h to obtain malt granules.

[0120] S2: Mix malt granules and water at a mass ratio of 1:5, and saccharify at 67°C until saccharification is complete. Filter to obtain wort.

[0121] S3: Boil the wort for 70 minutes. Add hops at 40 minutes and 65 minutes after the wort starts boiling. After boiling, allow the wort to swirl and settle.

[0122] S4: Cool the wort obtained from vortex sedimentation to 19°C and fill it into the fermentation tank from the bottom. The fermentation tank is lined with multiple layers of mesh, with a spacing of 25cm between the layers of mesh. Beer-specific yeast is fixed on the mesh. Ferment for 9 days.

[0123] S5: Cool to 5℃, add Polygonatum polysaccharide grafted with Australian wheat protein, and carry out post-fermentation for 19 days. Take the liquid from the uppermost layer of the membrane to obtain Polygonatum beer with stable foam.

[0124] Comparative Example 2

[0125] The difference between this comparative example and Example 8 is that no Polygonatum polysaccharide grafted onto Australian wheat protein was added, as detailed below:

[0126] A method for preparing foam-stable Polygonatum beer includes the following steps:

[0127] S1: Take malt and crush it to a particle size ≤0.03mm using the re-moistening crushing method. The conditions for the re-moistening crushing method are: 1% water content, temperature 40℃, and time 1h to obtain malt granules.

[0128] S2: Mix malt granules and water at a mass ratio of 1:5, and saccharify at 67°C until saccharification is complete. Filter to obtain wort.

[0129] S3: Boil the wort for 70 minutes. Add hops at 40 minutes and 65 minutes after the wort starts boiling. After boiling, allow the wort to swirl and settle.

[0130] S4: Cool the wort obtained by vortex sedimentation to 19°C, add Polygonatum hydrolysate at a rate of 1.5% of the wort mass, fill it into the fermentation tank from the bottom, the fermentation tank is lined with multiple layers of mesh film with a spacing of 25cm between the layers of mesh film, beer-specific yeast is fixed on the mesh film, and ferment for 9 days.

[0131] S5: Cool to 5℃ and carry out post-fermentation for 19 days. Take the liquid from the top layer of the membrane to obtain the foam-stable Huangjing beer.

[0132] Comparative Example 3

[0133] The difference between this comparative example and Example 8 is that an equal amount of yeast was directly added, as follows:

[0134] A method for preparing foam-stable Polygonatum beer includes the following steps:

[0135] S1: Take malt and crush it to a particle size ≤0.03mm using the re-moistening crushing method. The conditions for the re-moistening crushing method are: 1% water content, temperature 40℃, and time 1h to obtain malt granules.

[0136] S2: Mix malt granules and water at a mass ratio of 1:5, and saccharify at 67°C until saccharification is complete. Filter to obtain wort.

[0137] S3: Boil the wort for 70 minutes. Add hops at 40 minutes and 65 minutes after the wort starts boiling. After boiling, allow the wort to swirl and settle.

[0138] S4: Cool the wort obtained from vortex sedimentation to 19°C, add Polygonatum hydrolysate at a rate of 1.5% of the wort mass, fill the fermentation tank from the bottom, add beer-specific yeast, and ferment for 9 days;

[0139] S5: Cool to 5℃, add Polygonatum polysaccharide grafted with Australian wheat protein, and carry out post-fermentation for 19 days. Take the top layer of liquid to obtain Polygonatum beer with stable foam.

[0140] The foam holding value of the Polygonatum beer in the above embodiment was determined by the instrumental method in GB / T4928-2008. The foam holding values ​​were determined at the initial stage and after 6 months of storage at room temperature.

[0141] The content of foam active protein in Polygonatum beer was determined at the initial stage and after 6 months of storage at room temperature.

[0142] The results are shown in Table 2 below:

[0143] Table 2

[0144]

[0145]

[0146] Determination of beer clarity: The transmittance was measured at 660 nm using a 10 mL cuvette;

[0147] Determination of antioxidant capacity: DPPH free radical scavenging activity (DSA) was tested by taking 0.1 ml of a 1:1 diluted sample of Polygonatum odoratum beer and adding 2.9 ml of 6×10⁻⁶ ppm scavenging agent. -5A 1 mol / L DPPH solution was reacted at room temperature for 1 h, and then the scavenging rate was calculated by colorimetric analysis at a wavelength of 517 nm. The Trolox value was then calculated based on the standard curve, and the results are expressed as mmolTrolox value / L (mmolTE / L). The results are shown in Table 3.

[0148] Table 3

[0149] <![CDATA[Clarity T 660 > DSA (mmolTE / L) Example 8 90.2 4.93 Comparative Example 1 90.1 4.66 Comparative Example 2 90.2 4.02 Comparative Example 3 82.7 4.77 Beer sold in a certain city 84.9 1.45

[0150] Sensory evaluation: The sensory quality of Huangjing beer was evaluated by a panel of 10 experienced professionals. The evaluation focused on four aspects: color, aroma, taste, and style. The evaluation is shown in Table 4 below, and the results are presented in Table 5 below.

[0151] Table 4

[0152]

[0153]

[0154] Table 5

[0155] Appearance (20 points) Aroma (20 points) Taste (30 points) Style (30 points) Total Score Example 8 19 18 27 26 90 Comparative Example 1 14 17 27 26 84 Comparative Example 2 16 16 27 25 84 Comparative Example 3 15 17 25 23 80 Beer sold in a certain city 15 16 26 24 81

[0156] It should be noted that, although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for the preparation of a foam stable Polygonatum sibiricum beer, characterized by, The method comprises the following steps: S1: taking the dried rhizome of Polygonatum sibiricum, cleaning it, and then mixing it with 20% yellow rice wine to make it moist, placing it in a steamer to steam for 3 hours, taking it out, drying it to semi-dry, and then drying it at a constant temperature, and crushing it to 80 mesh; S2: stirring with 25 times the volume of water, placing it in a microwave oven, extracting for 50-70 seconds at a microwave intensity of 0.95 W / g, taking it out, and centrifuging to obtain the filtrate and residue of Polygonatum sibiricum; S3: adding savage reagent to the filtrate, filtering to obtain the supernatant, concentrating the supernatant, adding anhydrous ethanol to a concentration of 80%, and then placing it at 4°C for 24 hours, and centrifuging at 4000 r / min for 6-8 minutes, washing and drying the precipitate to obtain Polygonatum sibiricum polysaccharide; S4: taking the residue of Polygonatum sibiricum, adding 0.2 mol / L phosphate buffer solution, stirring for 4 hours, centrifuging at 10000 r / min for 15 minutes, taking the supernatant, adding ammonium sulfate to saturation, placing it at 4°C, centrifuging to obtain the precipitate, and then placing it in a 3500 Da dialysis bag to dialyze to obtain a Polygonatum sibiricum protein solution, and then freeze-drying to obtain Polygonatum sibiricum protein; S5: preparing a 7% Polygonatum sibiricum protein solution, adjusting the pH to 8.0 and the temperature to 45°C, adding trypsin, and then adding 0.5 mol / L NaOH solution dropwise to maintain the pH at 8.0, and then taking out the enzyme solution after reacting for 20-30 minutes, boiling in water for 10 minutes to inactivate the enzyme, adjusting the pH to 7.0 after cooling to room temperature, and then centrifuging at 3000 r / min for 20 minutes, and then freeze-drying the supernatant to obtain Polygonatum sibiricum protein hydrolysate; S6: taking malt, crushing it to a particle size of ≤0.03 mm by a moisture recovery crushing method to obtain malt particles; S7: stirring the malt particles with water at a mass ratio of 1:5, saccharifying at a temperature of 66-68°C until complete saccharification, and then filtering to obtain wort; S8: boiling the wort, controlling the boiling process time to 70 minutes, adding hops at 40 minutes and 65 minutes after the start of wort boiling, and then performing whirlpool sedimentation after boiling; S9: cooling the wort obtained by whirlpool sedimentation to 18-20°C, adding Polygonatum sibiricum protein hydrolysate, and then filling it into a fermentation tank from the bottom, placing multiple layers of net membranes in the fermentation tank, fixing special beer yeast on the net membranes, and then fermenting for 8-10 days; S10: cooling to 4-6°C, adding Polygonatum sibiricum polysaccharide grafted Australian malt protein, and then performing post-fermentation for 18-20 days, and then taking the liquid on the upper layer of the uppermost net membrane to obtain foam-stable Polygonatum sibiricum beer; The addition amount of the Polygonatum sibiricum protein hydrolysate in S9 is 0.5-2% of the mass of the wort; The spacing between the multiple layers of net membranes in S9 is 20-30 cm; The preparation method of the net membrane in S9 is: (1) uniformly dispersing aluminum silicate fibers in silica sol, slowly adding 15% ammonium chloride solution, and stirring; (2) adding nano-garnet powder and stirring uniformly; (3) transferring the mixture to a syringe in an electrospinning device to perform electrospinning, and obtaining an electrospun net membrane; (4) after the electrospun net membrane is gelled and hardened, taking it off from the receiving plate, drying it, and obtaining a net membrane with a pore size of 2-5 μm; (5) The mesh film is put into water for soaking, and then is put into an oven for drying sterilization at 200 DEG C, to obtain a sterilized mesh film; (6) A suspension of brewer's yeast cells at a concentration of 2 x 10 8 The sterilized mesh is then used to adsorb the yeast cells at 15°C for 30-40 min, and the mesh with the adsorbed yeast cells is then continuously cultured in a reactor at the same temperature for 2 h to obtain the mesh with the immobilized brewer's yeast. The mass ratio of the aluminum silicate fiber, the silica sol, the ammonium chloride and the nanometer garnet powder is 0.4:100:7:270; The preparation method of the polysaccharide grafted oat protein in S10 is as follows: (1) The polysaccharide and the oat protein obtained in S3 are respectively prepared into a polysaccharide solution and an oat protein solution with a mass fraction of 1%, and the two solutions are mixed in a volume ratio of 1: (1-2) and stirred uniformly; (2) After vacuum freeze-drying, the polysaccharide-mixture is obtained, and is placed in a desiccator with a saturated potassium bromide solution at the bottom and is reacted at 85 DEG C for 2 h; (3) The polysaccharide-mixture is dissolved in deionized water, dialyzed for 48 h, and then freeze-dried to obtain the polysaccharide grafted oat protein.

2. A process for the preparation of a foam stable Jatamansi beer as claimed in claim 1, wherein, The mass-volume ratio of the filter residue of the rhizoma polygonati and the phosphate buffer in S4 is 1 g: (30-35) mL.

3. A process for the preparation of a foam stable Polygonatum sibiricum beer as claimed in claim 1, wherein, The mass ratio of the trypsin and the rhizoma polygonati protein in S5 is 1.5:

100.

4. A process for the preparation of a foam stable Polygonatum sibiricum beer as claimed in claim 1, wherein, The conditions of the moisture regaining and crushing method in S6 are as follows: 1% water, 40 DEG C, and 1 h.

5. The foam-stabilized rhizoma polygonati beer prepared by the preparation method in any one of claims 1-4.

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