Preparation method and application of low-purine beer rich in Brassica rapa characteristic flavone

Abstract

The invention relates to the technical field of functional beer preparation, in particular to a preparation method and application of low-purine beer rich in characteristic flavone components from brassica rapa. Comprising the following steps: preparation of a brassica rapa extract, preparation of low-purine wort and three-stage addition of the brassica rapa extract: adding the extract in the step (1) in different process stages for three times so as to control the accumulative heating time of the extract in a high-temperature stage to be less than or equal to 20 minutes, adding the extract in a saccharification stage for the first time, and adding the extract in an amount which is 30-40% of the total amount of the extract; the second time of addition is 15-20 min before wort boiling, and the addition amount is 45-55% of the total amount of the extract; the third-time addition is performed at the later stage of fermentation, and the addition amount is 10-20% of the total amount of the extract. According to the method, through an innovative three-section type adding process, the accumulative heating time and the fusion stage of characteristic flavone components in the brassica rapa extract in the brewing process are accurately controlled, the activity of the brassica rapa extract is protected to the maximum extent, and the technical problems that the brassica rapa extract is poor in stability and low in retention rate in a beer brewing system are solved.

Description

Technical Field

[0001] This invention relates to the field of functional beer preparation technology, specifically to a beer with auxiliary uric acid-lowering function and its preparation method, and particularly to a method for preparing a beer with high flavonoid retention and low purine content by combining Chamaegu extract with a low-purine beer brewing process through a specific process. Background Technology

[0002] With increasing health awareness, the high purine content of traditional beer (usually exceeding 100 mg / L) and its potential to trigger or exacerbate hyperuricemia and gout have drawn growing attention. Developing low-purine beer has become an important direction for the industry. Conventional low-purine technologies mainly focus on raw material selection (such as using low-purine malt) and process optimization (such as utilizing purine-degrading enzymes), but these methods often focus on a single "harm reduction" goal and fail to endow the product with positive health benefits.

[0003] Brassica rapa L. is a plant used both as food and medicine. Its tuberous roots are rich in flavonoids (such as quercetin, kaempferol, and other aglycones and glycosides). Studies have shown that it has significant potential for antioxidant, anti-inflammatory, and uric acid reabsorption inhibition and uric acid excretion promotion. Introducing the characteristic flavonoids of Brassica rapa into beer holds promise for developing an innovative beverage that combines "low purine" and "aids in lowering uric acid."

[0004] However, effectively integrating plant-based active ingredients into the beer system faces significant challenges. The beer brewing process involves multiple steps, including mashing, boiling, and fermentation. The prolonged high-temperature boiling and intense fermentation environment easily lead to the degradation, polymerization, or loss of heat-sensitive and easily oxidized flavonoids, resulting in extremely low retention rates of active ingredients in the final product. If traditional one-time addition methods are used (such as adding them at the initial stage of mashing or boiling), most of the flavonoids will be destroyed during subsequent prolonged high-temperature boiling, resulting in severe functional loss and failing to achieve the expected health benefits.

[0005] Therefore, existing technologies lack a systematic solution that can efficiently and stably incorporate the characteristic flavonoid active ingredients of Chamaegu into low-purine beer systems while maintaining the traditional flavor and quality of beer, and ensure that they have high retention and high bioavailability in the final product. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a low-purine beer rich in the characteristic flavonoids of Chamaegu, its preparation method, and its application. Through an innovative "three-stage addition" process, the cumulative heating time and fusion stage of Chamaegu extract during the brewing process are precisely controlled to maximize the protection of its characteristic flavonoid activity. This solves the technical problems of poor stability and low retention rate of Chamaegu extract in the beer brewing system, ultimately resulting in a functional beer with low purine content (<50 mg / L), high total flavonoid content (90~115 mg / L), and high retention rate of characteristic flavonoids.

[0007] This invention is achieved through the following technical solution:

[0008] A method for preparing a low-purine beer rich in the characteristic flavonoids of Chamaegu is provided, comprising the following steps:

[0009] (1) Preparation of Chamaegu extract: Chamaegu tuberous root raw material is taken, washed, dried and crushed, and then water is added for reflux extraction at a temperature ≥85℃. After extraction, it is filtered, concentrated and dried to obtain Chamaegu extract powder.

[0010] (2) Preparation of low-purine wort: Low-purine barley malt with a purine content of <50mg / 100g is used, and after crushing, saccharification, filtration and boiling, wort with a total purine content of <50mg / L is obtained.

[0011] (3) Three-stage addition of Chamaegu extract: The extract obtained in step (1) is added three times at different process stages to control the cumulative heating time of the extract in the high-temperature stage to ≤20min, wherein:

[0012] The first addition is made during the saccharification stage, at a rate of 30-40% of the total extract volume.

[0013] The second addition should be made 15-20 minutes before the wort boils completely, and the amount added should be 45-55% of the total extract.

[0014] The third addition is made in the later stage of fermentation, and the amount added is 10-20% of the total extract.

[0015] In this technical solution, the essence of the three-stage addition is to break down the extract into smaller parts based on the different physicochemical environments at each stage of brewing, and then add them at the optimal time and in the optimal manner to minimize the loss of activity. The principle is broken down as follows:

[0016] First addition (initial saccharification): Utilizing a reducing environment for fusion. Saccharified mash (a mixture of crushed malt and water) is a strongly reducing environment rich in reducing sugars, amino acids, and natural antioxidants. At this stage (pH 5.2-5.4, 50-65℃), 30-40% of the extract is dissolved and added, providing a reducing protective environment for flavonoid molecules. The reducing substances in the mash preferentially react with oxygen, protecting the active sites such as the phenolic hydroxyl groups of the flavonoid nucleus from early oxidation and stabilizing its chemical structure. The mild temperature (far below boiling temperature) allows the flavonoids to fully dissolve and disperse, and initially fuse with polysaccharides and proteins in the malt through hydrogen bonds and hydrophobic interactions, forming a natural protective micelle, laying the foundation for subsequent high-temperature treatment.

[0017] The second addition (15-20 minutes before the end of boiling): Utilizing instantaneous high temperature to achieve sterilization and minimize thermal degradation, the maximum proportion (45-55%) of the extract is added just before the end of boiling, maximizing the necessary treatment effect with the shortest exposure time. High temperature of 100℃ is a necessary step to kill bacteria in the wort and coagulate excess protein. Traditional single-addition exposes flavonoids to high temperatures for more than 60 minutes, while this invention strictly controls the exposure time at 100℃ to ≤20 minutes. 20 minutes of boiling is sufficient to achieve instantaneous and thorough sterilization, meeting process hygiene requirements. Compared to full boiling, the high-temperature heating time is compressed by more than 2 / 3, greatly inhibiting the degradation reaction of the most heat-sensitive components such as flavonoid aglycones, achieving a high retention rate.

[0018] The third addition (late fermentation): This late addition compensates for losses and locks in the final concentration. At the end of the main fermentation stage (days 4-5), yeast proliferation has essentially stopped, and most of the condensed matter has precipitated. At this point, the remaining 10-20% of the extract is dissolved in deoxygenated water and aseptically added. This directly replenishes the flavonoids lost in the earlier stages, calibrating the flavonoid concentration in the final product to the target range. Furthermore, at this point, the wort has been converted to young beer, and the alcohol content and pH environment better dissolve and stabilize the flavonoids. Simultaneously, this avoids interference with yeast activity and early flavor development.

[0019] The core principle of this invention is the construction of a spatiotemporally differentiated active ingredient delivery and protection system. Spatially, flavonoids are allowed to enter the reducing environment of the mashing pot, the instantaneous high temperature of the boiling pot, and the compensating environment of the fermentation tank. Temporally, the addition is precisely anchored at three key nodes: the initial stage of the process, the final stage of the process, and the later stage of the biological process. This intelligently utilizes and adapts to the different stages of the brewing process itself, transforming the mashing, boiling, and fermentation processes into a segmented, progressive process of active ingredient protection and integration. This achieves the successful embedding of highly active functional ingredients into the traditional beer system.

[0020] Furthermore, the preparation of Chamaegu extract in step (1) specifically includes: the raw material is washed and dried, and then pulverized to pass through a 20-mesh sieve; the ratio of feed amount to water amount is 1:6, and the reflux extraction is performed 3 times, each time for 2 hours; the filtrates are combined, concentrated under reduced pressure to a specific gravity of 1.13 (heat measurement), and then spray dried with an inlet air temperature of 150℃ and an outlet air temperature of 90℃ to obtain a powder with a moisture content of ≤7%, which is then pulverized to pass through an 80-mesh sieve.

[0021] Furthermore, the saccharification process of low-purine wort in step (2) is as follows: material-to-water ratio 1:3.5, protein rest at 50℃ for 15 min, saccharification at 65℃ for 60 min, enzyme inactivation at 78℃ for 10 min; boiling time 60~70 min, and wort concentration 12~14°P.

[0022] Furthermore, in step (3), the first addition is as follows: the extract is dissolved in 3 times the volume of sterile water and then added to the saccharification pot together with the malt, and fused for 75 minutes at pH 5.2~5.4 and temperature 50~65℃.

[0023] Furthermore, in step (3), the second addition is as follows: the extract is directly added to the boiling wort, and the heating time is ≤20min.

[0024] Furthermore, in step (3), the third addition is specifically as follows: on the 4th to 5th day of fermentation, the extract is dissolved in deoxygenated water and added through a sterile pipeline after the concentration reaches 50 mg / mL.

[0025] Furthermore, in step (3), the total amount of Chamaegu extract added in the three-stage addition process accounts for 0.15~0.16% of the total feed amount.

[0026] A beer prepared by the method described above for preparing beer that lowers uric acid using characteristic flavonoid components of Chamaegu has a purine content of <50mg / L and a flavonoid content of 90~115mg / L. The characteristic flavonoids, including rutin, baicalin, and daidzein, are derived from Chamaegu extract added through a three-stage addition process.

[0027] Application of a low-purine beer rich in Chamaegu characteristic flavonoids in the preparation of beverages suitable for people with hyperuricemia or metabolic syndrome.

[0028] The beneficial effects of this invention are:

[0029] I. High Retention of Flavonoid Activity: Through an innovative three-stage addition strategy, the time for most of the flavonoid extract (45-55%) to be placed in a high-temperature environment is strictly limited to within 20 minutes, and the reducing environment of the saccharification stage is utilized for protection. Supplementation is then carried out in the later stages of fermentation, systematically avoiding the prolonged thermal degradation and process losses caused by traditional one-time addition. Experiments show that using the method of this invention, the retention rate of characteristic flavonoids of Chaga mushroom in the final product can reach over 90%, far exceeding the approximately 60% of the traditional process.

[0030] II. Balancing Functionality and Flavor: The beer prepared by this invention not only successfully increases the flavonoid content to a functional level (≥90 mg / L), but also, through a phased fusion process, harmonizes the flavor of plant extracts with the original hop and malt flavors of the beer, avoiding medicinal or unpleasant off-flavors and maintaining the typical flavor characteristics and taste of the beer.

[0031] III. Clear Health Orientation: The product possesses both low-purine (<50 mg / L) and high-flavonoid properties. The low-purine characteristic reduces the risk to people with hyperuricemia, while the high content of Chaga mushroom's characteristic flavonoids may provide potential auxiliary uric acid-lowering functions through mechanisms such as inhibiting xanthine oxidase activity and promoting uric acid excretion. It is a suitable health drink choice for people with hyperuricemia and metabolic syndrome.

[0032] IV. Stable and controllable process: The extract preparation, wort control and three-stage addition process parameters provided by this invention are clear, easy to realize industrial production, and the product quality is stable and uniform.

[0033] V. Synergistic Effect of Core Functional Components and Clear Uric Acid-Lowering Efficacy: The beer prepared by this invention achieves efficient enrichment and retention of three core characteristic flavonoid substances for lowering uric acid: rutin, baicalin, and daidzein. These three substances work synergistically through different mechanisms of action: inhibiting uric acid synthesis, promoting uric acid excretion, and protecting liver and kidney function. Animal experiments have shown that, within the corresponding daily drinking dosage range for adults, the product can significantly reduce serum uric acid levels in hyperuricemia model animals, inhibit the activity of key enzymes in uric acid synthesis, promote uric acid excretion, and alleviate liver and kidney damage caused by hyperuricemia. It has a clear auxiliary effect in lowering uric acid and no obvious dose-related side effects.

[0034] VI. Significant enrichment effect of active ingredients and outstanding technological advantages: The three-stage addition process achieves synergistic enrichment and retention of characteristic flavonoid active ingredients of Chaga mushroom. The contents of core uric acid-lowering substances such as rutin, baicalin, and daidzein are significantly higher than the simple summation of the single-stage addition group, rather than simply adding materials in stages. This fully demonstrates the significant advantages of this process in the protection, fusion, and enrichment of active ingredients, and provides a brand-new technical approach for integrating plant active ingredients into the beer brewing system. Attached Figure Description

[0035] Table 1 is a comparison table of the detection and effects of the product in Example 3 of the present invention and the comparative product.

[0036] Table 2 is a comparison table of the detection data of flavonoid content in beer under different addition methods of the present invention;

[0037] Figure 1 is a schematic diagram of dosage conversion for animal experiments on the auxiliary uric acid lowering effect of the product in Example 3 of the present invention;

[0038] Figure 2 shows the effect of the product of Example 3 of the present invention on the growth parameters of hyperuricemia model mice;

[0039] Figure 3 shows the effect of the product of Example 3 of the present invention on serum biochemical indicators of hyperuricemia model mice;

[0040] Figure 4 shows the effect of the product of Example 3 of the present invention on uric acid synthesis and liver damage-related indicators in a hyperuricemia model mouse.

[0041] Figure 5 shows the effect of the product of Example 3 of the present invention on the level of inflammatory factors in the kidneys of mice with hyperuricemia.

[0042] Figure 6 shows the effect of the product of Example 3 of the present invention on the pathological morphology of kidney tissue in mice with hyperuricemia (HE section). Detailed Implementation

[0043] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0044] Example 1: Preparation of Chamaegu Extract

[0045] 1000 kg of fresh Chamaegu tubers were washed twice with tap water, drained, and then dried in hot air at 60℃ until the moisture content was ≤10%. The tubers were pulverized and passed through a 20-mesh sieve. The pulverized raw material was placed in an extraction tank, and 6 times the volume (6000 L) of purified water was added. The mixture was heated to 90℃ and refluxed at a slight boiling state for 2 hours. The mixture was filtered, and the filtrate was collected. The residue was subjected to the same extraction process twice. The three filtrates were combined and filtered using a plate and frame filter press to remove fine residue. The filtrate was pumped into a vacuum concentrator, and the temperature was controlled at ≤80℃ to concentrate it to a thick extract with a relative density of 1.13 (measured at 60℃). The extract was spray-dried, with the inlet air temperature controlled at 150℃ and the outlet air temperature at 90℃, yielding a pale yellow powder with a moisture content of 6.2%. This powder was pulverized using a universal pulverizer and passed through an 80-mesh sieve to obtain approximately 85 kg of Chamaegu water extract powder. HPLC analysis showed that the total flavonoid content (calculated as rutin) was 5.8%.

[0046] Example 2: Preparation of low-purine wort

[0047] 100 kg of low-purine barley malt (purine content 42 mg / 100 g) was pulverized using a roller mill. The malt was added to a mashing tank with 350 L of purified water. The initial temperature was 50°C, and protein rest was allowed for 15 min. The temperature was then raised to 65°C and maintained for 60 min of mashing. Finally, the temperature was raised to 78°C and maintained for 10 min to inactivate the enzymes. After mashing, the malt was pumped into a filter tank to obtain the first wort, which was then washed twice with 78°C hot water. The wort was combined, and the original wort concentration was measured to be approximately 11.5°P. The wort was then pumped into a boiling kettle and heated to boiling for a total boiling time of 65 min. Hops were added in three stages: 50% of the total hops were added at the initial boil, 30% in the last 30 min, and 20% in the last 5 min. After boiling, the wort was passed through a vortex settling tank to remove hot coagulated material, yielding a clear, finalized wort with a concentration of 12.8°P. Sampling and testing revealed that the total purine content in the wort was 48 mg / L.

[0048] Example 3: Preparation of low-purine beer rich in Chamaegu characteristic flavonoids

[0049] Raw materials: Chamaegu extract powder (total flavonoid content 5.8%) prepared in Example 1 and low-purine wort (total purine content 48 mg / L) prepared in Example 2.

[0050] Total addition calculation: For a target production of 1000 L of beer, the total addition of Chamaegu extract powder is 1.85 kg (0.155% of the total feed amount), added in three stages.

[0051] Three-stage addition:

[0052] First addition: Weigh 0.65 kg of extract powder (35.1% of the total amount), dissolve it in 1.95 L of sterile water, and add it to the saccharification tank along with the crushed malt during saccharification. The saccharification process is carried out at pH 5.3, temperature 50-65℃, and for 75 min of incorporation.

[0053] Second addition: Weigh 0.95 kg of extract powder (accounting for 51.4% of the total amount) and add it directly to the boiling wort 18 minutes before the wort boils. Heat it at 100°C for 18 minutes before the boiling ends.

[0054] Third addition: Weigh 0.25 kg of extract powder (accounting for 13.5% of the total amount) and dissolve it in 5 L of deoxygenated sterile water on the 5th day after the start of the main fermentation (inoculation with the yeast below, fermentation at 10°C). Then, inject it into the fermenter through a sterile addition pump.

[0055] Subsequent processes: After the third addition, fermentation continues until diacetyl reduction reaches the target. The mixture is then cooled to 0°C and stored for 7 days. After diatomaceous earth filtration, membrane filtration, and aseptic bottling, the finished beer is obtained.

[0056] Comparative Example

[0057] The raw materials and processes for this comparative example are the same as those for Example 3, except that the Chamaegu extract is added all at once at the beginning of the wort boiling process, totaling 1.85 kg.

[0058] The beer prepared in Example 3 was tested and compared with the beer prepared in the comparative example. The product test results and effect comparison are shown in Table 1 below.

[0059] Table 1. Comparison of Detection and Effects between Example 3 Product and Comparative Product Testing items Add group only in the first stage (saccharification stage) Add the group only in the second stage (towards the end of boiling). Add the group only in the third stage (late fermentation stage) Example 3 Product (Three-stage addition) Comparison Beer Original wort concentration (°P) 12.8 12.8 12.8 12.8 12.8 Alcohol content (% vol) 5.2 5.2 5.2 5.2 5.2 Total purine content (mg / L) 46 46 46 46 58 Total flavonoid content (mg / L) 45 55 60 102 15 Flavonoid retention rate (%) 66.7 75 80.1 91.5 52.3 Flavor Evaluation It has a slight herbal flavor, but the integration with the beer flavor is average. It has a distinct herbal flavor and a slightly astringent taste. The herbal notes are prominent, masking some of the hop aromas. It has a harmonious aroma of malt and hops, with a slight hint of vegetal fragrance, and no off-odors. It has no herbal flavor and has typical malt and hop aromas.

[0060] As shown in Table 1, this invention, through a three-stage addition process, successfully increased the flavonoid content in beer to 102 mg / L, with a flavonoid retention rate as high as 91.5%, significantly higher than the 58 mg / L and 52.3% retention rate of the single-stage addition comparison. Simultaneously, the purine content of the product from this invention was effectively controlled below 50 mg / L, meeting the low-purine requirements. Flavor evaluation also showed that the staged addition process better integrates the chamaegu flavor into the beer system, avoiding the generation of unpleasant off-flavors.

[0061] Example 4: Effects of different total addition amounts

[0062] Three batches of beer were prepared by maintaining a fixed three-stage addition ratio (35%:50%:15%) and varying the total addition amount. The flavonoid content of the final product was measured, and the results are as follows:

[0063] Adding 1.8 kg / 1000L: The final product contains 95 mg / L of flavonoids.

[0064] Adding 1.85 kg / 1000L: The final product contains 102 mg / L of flavonoids.

[0065] Adding 1.92 kg / 1000L: The final product contains 112 mg / L of flavonoids.

[0066] The results show that, under the process of the present invention, when the total amount of extract added is in the range of 0.15% to 0.16%, an ideal product with a flavonoid content of 90 to 115 mg / L can be obtained.

[0067] Example 5: Detection of flavonoid content and verification of uric acid-lowering efficacy

[0068] To further verify the enrichment effect of the three-stage addition process of the present invention on the characteristic flavonoids of Chamaegu and the auxiliary uric acid-lowering function of the finished beer, liquid chromatography-mass spectrometry (LC-MS) was used to detect the total content of flavonoids in the group without Chamaegu extract, the group with only one stage of Chamaegu extract addition (first stage / second stage / third stage), and the three-stage addition group (product of Example 3 of the present invention). At the same time, an animal model of hyperuricemia was constructed to verify the auxiliary uric acid-lowering effect of the finished beer. The specific results are as follows.

[0069] 5.1 Results of Flavonoid Content Detection

[0070] This test focused on three core functional substances: rutin, baicalin, and daidzein. Other flavonoids were used as auxiliary indicators. The results showed that the flavonoid content in the group without the addition of Chaga mushroom extract was the same as that in the ordinary control beer, with extremely low overall content and no functional flavonoid enrichment effect. Only the single-stage addition group showed a slight enrichment of flavonoids, with the contents of rutin, baicalin, and daidzein being about 1 / 3 of those in the three-stage addition group, and the overall flavonoid richness was lower than that in the three-stage addition group. In the three-stage addition group (Example 3), the contents of rutin, baicalin, and daidzein achieved a leapfrog enrichment, reaching 967.32 ng / ml, 971.46 ng / ml, and 303.36 ng / ml, respectively, which was much higher than the simple sum of the single-stage addition groups. The contents and richness of other flavonoids such as apigenin, luteolin, and hesperidin were also significantly increased. Specific test data are shown in Table 2 below.

[0071] Table 2. Comparison of flavonoid content in beer under different addition methods

[0072] Analysis of the data in Table 2 shows that the stability and enrichment behavior of different flavonoids in the Chamaegu extract differ in this brewing system. The content of components such as scutellarin fluctuated slightly after the addition of the extract, possibly related to the process response of the inherent components of the beer matrix. These components are not the characteristic flavonoids of Chamaegu of interest in this invention and do not affect the evaluation of the enrichment effect of the core functional components (rutin, baicalin, and daidzein). The contents of baicalin, quercetin, and kaempferol were relatively stable in each experimental group, indicating that the three-stage addition process of this invention has good compatibility with these substances and can effectively prevent their degradation. More importantly, the contents of core functional substances such as rutin, baicalin, and daidzein in the three-stage addition group (product of Example 3 of this invention) (967.32, 971.46, and 303.36 ng / ml, respectively) achieved a significant increase, far exceeding the simple sum of the contents of each single-stage addition group, exhibiting a significant synergistic enrichment effect.

[0073] The above results fully demonstrate that the three-stage addition process of the present invention is not a simple step-by-step feeding process, but rather achieves efficient retention and synergistic enrichment of the characteristic flavonoid active ingredients of Chamaegu (especially the core uric acid-lowering functional substances) through reducing protection during the saccharification stage, short-term high-temperature fusion at the end of boiling, and loss compensation during the later stage of fermentation. This fundamentally solves the technical problem of poor stability and low retention rate of flavonoids in the beer brewing system.

[0074] This invention utilizes a three-stage additive process to enrich three core substances: rutin, baicalin, and daidzein. These substances provide a solid material foundation for the product's auxiliary uric acid-lowering function. The uric acid-lowering mechanisms of these three substances are clear and synergistic: ① Rutin significantly inhibits the activity of xanthine oxidase (XOD), reducing uric acid synthesis in the body, while simultaneously enhancing the body's antioxidant capacity and alleviating oxidative stress damage caused by hyperuricemia; ② Baicalin effectively inhibits the reabsorption of uric acid by the kidneys, promoting uric acid excretion through urine, reducing serum uric acid concentration, and protecting the kidneys, reducing damage to kidney tissue caused by hyperuricemia; ③ Daidzein can lower blood uric acid levels by regulating uric acid metabolism pathways and has good anti-inflammatory activity, alleviating joint inflammation caused by hyperuricemia. These three substances achieve a synergistic uric acid-lowering effect through multiple pathways of "reducing synthesis, promoting excretion, and protecting organs."

[0075] 5.2 Animal experiments verifying the uric acid-lowering effect

[0076] Male KM mice aged 6-8 weeks were used as experimental subjects, with 10 mice in each group to construct a mouse model of hyperuricemia. The following groups were established: a normal control group, a model group, a regular beer intervention group, a low-dose intervention group for the product of Example 3 of this invention, and a high-dose intervention group for the product of Example 3. An experiment was conducted to verify the uric acid-lowering efficacy of the product. The low-dose dose of the product of Example 3 was 30 μl / g, and the high-dose dose was 60 μl / g. The specific conversion for human consumption is shown in Figure 1. The intervention continued until the end of the experimental period. Mouse growth parameters, serum biochemical indicators, liver uric acid synthesis, and liver damage-related indicators were measured to verify the product's auxiliary uric acid-lowering efficacy.

[0077] 5.2.1 Growth Parameter Results

[0078] There was no significant difference in the initial body weight of the mice in each group; Figure 2 As shown, after modeling, the final body weight of mice in the model group was significantly lower than that in the normal group, while the liver and kidney indices were significantly increased, suggesting that the hyperuricemia modeling process may have affected the growth status and liver and kidney organs of mice. Compared with the model group and the ordinary beer intervention group, the weight loss trend of mice in the Example 3 product intervention group was alleviated, and the organ indices were closer to normal levels, with the improvement trend of the high-dose group being better than that of the low-dose group. These results preliminarily indicate that the Example 3 product may have the effect of reducing hyperuricemia-related bodily damage, and its effect is better than that of ordinary beer, suggesting that its efficacy may be related to the enriched chamaegu flavonoids, rather than common components such as alcohol.

[0079] 5.2.2 Serum biochemical index results

[0080] like Figure 3 As shown, compared with the normal group, the model group mice had significantly higher serum uric acid (UA), blood urea nitrogen (BUN), and creatinine (Cr) levels, while urinary uric acid content was lower, indicating that the modeling was successful in inducing uric acid metabolism disorder and biochemical signs of renal function impairment. After intervention with the product in Example 3, compared with the model group and the ordinary beer group, serum UA, BUN, and Cr levels showed a significant decreasing trend, while urinary uric acid content rebounded. These results indicate that the product in Example 3 can effectively regulate uric acid metabolism in hyperuricemia model mice, help reduce serum uric acid levels, and improve related renal function impairment indicators. The rebound in urinary uric acid content suggests that its mechanism of action includes promoting uric acid excretion through the kidneys.

[0081] 5.2.3 Results of hepatic uric acid synthesis and liver injury-related indicators

[0082] like Figure 4As shown, the activities of xanthine oxidase (XOD) and the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and adenosine deaminase (ADA), which reflect liver damage, were significantly higher in the liver tissue of the model group mice than in the normal group, suggesting hyperuricemia in the liver and hepatocellular damage. After intervention with the product of Example 3, especially compared with the ordinary beer intervention group, the activities of these enzymes were more effectively inhibited. This result proves that the product of Example 3 can significantly inhibit the activity of XOD, a key enzyme in uric acid synthesis, which may be one of the important mechanisms by which it reduces serum uric acid levels. At the same time, its superior improvement effect on liver damage indicators (AST, ALT, ADA) indicates that the chamaegu flavonoids contained in the product of Example 3 may have the effect of protecting liver function and alleviating liver damage related to hyperuricemia.

[0083] 5.2.4 Detection of renal inflammatory factor levels

[0084] like Figure 5 As shown, this section detects the levels of four chronic inflammatory factors—TNF-α, IL-1β, IL-6, and IL-8—in the kidney tissue of hyperuricemia model mice. The corresponding groups are: NC group (normal group), M group (model group), LKB group (low-dose intervention group of product in Example 3), HKB group (high-dose intervention group of product in Example 3), and PC group (positive drug control group). Figure 5 Data are expressed as mean ± standard deviation. "**" indicates a highly significant difference compared to the NC group (P<0.01), and "##" indicates a highly significant difference compared to the M group (P<0.01).

[0085] In the NC group, the levels of various inflammatory factors in the kidney tissue of mice remained at baseline, with no obvious inflammatory response. Compared with the NC group, the levels of TNF-α, IL-1β, IL-6, and IL-8 in the kidneys of M group mice were significantly increased (**P<0.01), indicating that hyperuricemia had induced a significant chronic inflammatory response in the mouse kidneys, which is one of the important mechanisms of kidney damage caused by hyperuricemia. After low-dose intervention with the product in Example 3, the levels of various inflammatory factors in the kidneys of LKB group mice were significantly lower than those in M ​​group (##P<0.01), and the inflammatory response was effectively alleviated. The inflammatory factor regulation effect of HKB group (high-dose intervention) was more prominent, with the levels of factors such as TNF-α and IL-1β further reduced, approaching the normal levels of the NC group. The improvement effect of inflammatory factors in the kidneys of PC group mice was similar to that of HKB group, and the levels of each factor were significantly lower than those in M ​​group.

[0086] The above results indicate that the product of Example 3 can effectively inhibit the chronic inflammatory response of the kidneys in mice induced by hyperuricemia, and the regulatory effect of high-dose intervention is better, demonstrating a certain dose-response relationship. Its anti-inflammatory effect has a similar regulatory efficacy to that of positive control drugs.

[0087] 5.2.5 Pathological observation of kidney HE sections

[0088] like Figure 6 As shown, this section uses HE staining to observe the histopathological morphology of kidney tissue in hyperuricemia model mice. The corresponding group labels are: NC group (normal group), M group (model group), LKB group (low-dose intervention group of product in Example 3), HKB group (high-dose intervention group of product in Example 3), and PC group (positive drug control group). Yellow arrows indicate glomeruli and blue arrows indicate renal tubules.

[0089] The kidney tissue pathology of mice in the NC group was clear, with regular glomeruli of uniform size and shape, and regular tubular lumens, without tissue vacuolation or structural abnormalities. Compared with the NC group, mice in the M group showed significant kidney pathological damage, characterized by marked glomerular atrophy and irregular morphology, significant dilation of the glomerular capsule and tubular lumen, and vacuolation of the kidney tissue, indicating that hyperuricemia had caused organic damage to the kidneys of mice. After low-dose intervention with the product in Example 3, the kidney pathological damage of mice in the LKB group was alleviated to some extent, the degree of glomerular atrophy was reduced, and the dilation of the tubular lumen and tissue vacuolation were improved compared with the M group, but slight structural disorder still existed. The improvement in the kidney tissue pathology of mice in the HKB group (high-dose intervention) was more significant, with the glomerular morphology basically restored to regularity, the degree of dilation of the capsule and tubular lumen significantly reduced, tissue vacuolation basically alleviated, and the kidney structure approached the normal state of the NC group. The improvement in kidney pathological damage of mice in the PC group was similar to that in the HKB group, and the structural abnormalities of the glomeruli and tubules were effectively corrected.

[0090] The above results indicate that the product of Example 3 can effectively alleviate the pathological damage to the kidneys of mice caused by hyperuricemia, and the improvement effect is better with high-dose intervention. Its kidney protective effect has a similar regulatory effect to that of positive control drugs.

[0091] 5.3 Experimental Conclusions

[0092] The results of flavonoid content detection show that the three-stage addition process of this invention can achieve efficient enrichment of characteristic flavonoids of Chamaegu, especially significantly increasing the content of three core uric acid-lowering substances: rutin, baicalin, and daidzein. Animal experiments further demonstrate that the product prepared in Example 3 of this invention can effectively reduce serum uric acid levels in model animals, accompanied by inhibition of liver XOD activity, increased uric acid excretion in urine, and improvement of liver and kidney damage indicators. This suggests that it may exert its uric acid-lowering effect through multiple pathways, including inhibiting uric acid synthesis, promoting uric acid excretion, and protecting liver and kidney function. Moreover, the improvement effect is significantly better than that of ordinary beer, showing a certain dose-response relationship within the experimental dosage range. Furthermore, based on body surface area conversion, the experimental dosage is within the range of daily beer consumption for adults, providing a basis for further application research of this product.

[0093] The low-purine beer rich in characteristic flavonoids of Chamaegu prepared by the three-stage addition process of this invention was subjected to comprehensive performance testing. The results showed that the total purine content of the product was 46 mg / L, which meets the low-purine standard of < 50 mg / L; the total flavonoid content was 102 mg / L, which is within the functional content range of 90~115 mg / L; sensory evaluation showed that the product has a harmonious malt aroma and hop aroma, with a slight Chamaegu herbal aroma, no off-flavors, and maintains the typical flavor characteristics and taste of beer.

[0094] In summary, the results of the above embodiments show that the present invention, through a precise three-stage addition process, successfully enriches high levels of the characteristic flavonoid active ingredients of Chamaegu while achieving the low-purine properties of beer. This gives the product three core functions: low purine, high flavonoid, and auxiliary uric acid reduction. Moreover, the process parameters are clear, stable, and controllable, making it easy to industrialize and produce products with uniform quality. Consuming this type of beer can reduce the risk of gout caused by excessive uric acid due to high purine intake.

[0095] This invention effectively solves the problem of easy degradation of plant active ingredients in beer brewing through a unique three-stage addition process, and successfully prepares an innovative beer with both low purine and high functional flavonoid content, which has good application prospects.

[0096] Of course, the above description is not limited to the examples above. Technical features not described in this invention can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solutions of this invention and are not intended to limit this invention. This invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention do not depart from the spirit of this invention and should also fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a low-purine beer rich in characteristic flavonoids of Chamaegu, characterized in that: Includes the following steps: (1) Preparation of Chamaegu extract: Chamaegu tuberous root raw material was washed, dried and crushed, and then water was added for reflux extraction at a temperature ≥85℃. After extraction, it was filtered, concentrated and dried to obtain Chamaegu extract powder. (2) Preparation of low-purine wort: Low-purine barley malt with a purine content of <50mg / 100g is used, and after crushing, saccharification, filtration and boiling, wort with a total purine content of <50mg / L is obtained. (3) Three-stage addition of Chamaegu extract: The extract obtained in step (1) is added three times at different process stages to control the cumulative heating time of the extract in the high-temperature stage to ≤20min, wherein: The first addition is made during the saccharification stage, at a rate of 30-40% of the total extract volume. The second addition should be made 15-20 minutes before the wort boils completely, and the amount added should be 45-55% of the total extract. The third addition is made in the later stage of fermentation, and the amount added is 10-20% of the total extract.

2. The method for preparing low-purine beer rich in characteristic flavonoids of Chamaegu according to claim 1, characterized in that: The preparation of Chamaegu extract in step (1) specifically includes: the raw material is washed and dried, and then pulverized to pass through a 20-mesh sieve; the ratio of feed amount to water amount is 1:6, and the reflux extraction is performed 3 times, each time for 2 hours; the filtrates are combined, concentrated under reduced pressure to a specific gravity of 1.13 (heat measurement), and then spray dried with an inlet air temperature of 150℃ and an outlet air temperature of 90℃ to obtain a powder with a moisture content of ≤7%, which is then pulverized to pass through an 80-mesh sieve.

3. The method for preparing low-purine beer rich in characteristic flavonoids of Chamaegu according to claim 1, characterized in that: The saccharification process for low-purine wort in step (2) is as follows: material-to-water ratio 1:3.5, protein rest at 50℃ for 15 min, saccharification at 65℃ for 60 min, enzyme inactivation at 78℃ for 10 min; boiling time 60~70 min, and wort concentration 12~14°P.

4. The method for preparing low-purine beer rich in characteristic flavonoids of Chamaegu according to claim 1, characterized in that: In step (3), the first addition is as follows: the extract is dissolved in 3 times the volume of sterile water and then added to the saccharification pot together with the malt. The mixture is then fused for 75 minutes at pH 5.2~5.4 and temperature 50~65℃.

5. The method for preparing low-purine beer rich in characteristic flavonoids of Chamaegu according to claim 1, characterized in that: In step (3), the second addition is as follows: the extract is directly added to the boiling wort and heated for ≤20 minutes.

6. The method for preparing low-purine beer rich in characteristic flavonoids of Chamaegu according to claim 1, characterized in that: In step (3), the third addition is specifically: on the 4th to 5th day of fermentation, the extract is dissolved in deoxygenated water and added through a sterile pipeline after the concentration reaches 50 mg / mL.

7. The method for preparing low-purine beer rich in characteristic flavonoids of Chamaegu according to claim 1, characterized in that: In step (3), the total amount of Chamaegu extract added in the three-stage addition process accounts for 0.15~0.16% of the total feed amount.

8. A beer prepared by the method of any one of claims 1 to 7 for preparing beer that lowers uric acid using characteristic flavonoid components of Chamaegu, wherein the purine content is <50mg / L, the flavonoid content is 90~115mg / L, and the rutin, baicalin and daidzein in the flavonoids are derived from Chamaegu extract incorporated through a three-stage addition process.

9. The use of the beer of claim 8 in the preparation of a beverage suitable for people with hyperuricemia or metabolic syndrome.

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