Hami characteristic fruit compound fermentation craft fruit beer and preparation method thereof

Abstract

The invention relates to the technical field of fermented fruit beer, and discloses composite fermented craft fruit beer with Hami characteristic fruits and a preparation method of the composite fermented craft fruit beer. Special fruits such as Hami melons, grapes, Chinese dates and sea-buckthorn in the Hami region are used as core raw materials, yeast, malt and hops are used as auxiliary materials, and the fruit wine is prepared through pretreatment, chemical-biological composite acid reduction, sugar regulation and sterilization, low-temperature staged fermentation, VC and EDTA-2Na compound browning inhibition, low-temperature ageing and sterile filling. According to the method, fruit acid, high sugar and low pain point are overcome through composite acid reduction, fruit aroma and nutrition are reserved through low-temperature fermentation, browning is prevented through a compound inhibitor, fruits are used for replacing part of grain raw materials, grain consumption is reduced, the concept of saving resources is met, the Hami forest fruit industry is promoted to be upgraded, and differentiated high-quality products are provided for the craft market.

Description

Technical Field

[0001] This invention belongs to the field of fermented fruit beer technology, specifically referring to a Hami-style fruit compound fermented craft beer and its preparation method. Background Technology

[0002] Traditional industrial beer production mainly relies on grain crops such as barley malt, wheat malt, and rice as core raw materials. However, the consumption of grain raw materials for beer is increasing year by year, which not only increases production costs but also puts pressure on our food security.

[0003] In recent years, single-flavor industrial beers have struggled to meet the diverse demands of the market, leading to the rapid rise of the craft beer segment. Fruit beer, an innovative beverage that blends the natural flavors of fruit with the rich taste of beer, has gradually become a popular choice for dining, entertainment, and family gatherings, catering to consumers of all ages and demonstrating significant market potential, thanks to its unique flavor profile and rich nutritional value. However, existing fruit beer production technologies still face several pressing challenges.

[0004] On the one hand, most existing fruit beer production processes use the maceration method, which involves simply mixing fruit juice with beer base, macerating it, and then filtering it. While this method is simple to operate, it has low flavor extraction efficiency, making it difficult to fully preserve the natural flavor and nutrients of the fruit. Furthermore, unpleasant odors can easily be generated during the maceration process, resulting in poor flavor harmony and insufficient stability in the product. A few fruit beer production processes that use fermentation have failed to optimize parameters based on the characteristics of the fruit raw materials, resulting in a lower level of process maturity.

[0005] On the other hand, fruit beer production faces significant constraints due to the characteristics of its raw materials. Suitable fruits for brewing fruit beer (such as sea buckthorn and jujubes from Hami) generally have high organic acid content and relatively low sugar content. Traditional fermentation processes lack effective acid-sugar regulation techniques, easily leading to fermentation disruptions. This results in a final product with a sour and astringent taste, insufficient aroma, and an inability to balance fruit flavor with the rich texture of beer. Simultaneously, polyphenols in beer are prone to oxidative browning during storage. Current technologies lack efficient browning inhibition methods that do not negatively impact product flavor, causing fruit beer to darken in color and decline in quality during storage, severely affecting shelf life and market acceptance.

[0006] In addition, existing fruit beer products mostly rely on single fruit raw materials or conventional processes, lacking customized production technologies for the special fruit resources of specific production areas. This makes it difficult to form a differentiated competitive advantage and fails to fully leverage the value of local specialty agricultural resources, thus failing to effectively drive the upgrading of the forestry and fruit industry in the production areas.

[0007] To address the shortcomings of existing technologies, there is an urgent need to develop a fruit beer craft brewing technology that can fully utilize unique fruit resources, optimize process parameters, solve acid-sugar imbalance and browning problems, and improve product flavor and stability. This would meet the market demand for high-quality fruit beer, while reducing grain consumption, promoting the healthy development of local forestry and fruit industries, and providing differentiated product solutions for the craft beer market. Summary of the Invention

[0008] To address the above issues, this paper proposes a Hami-specific fruit-based compound fermentation craft beer and its preparation method. This addresses the shortcomings of existing technologies, such as the high reliance on grain raw materials in traditional industrial beer production, which increases costs, impacts food security, and contradicts resource conservation principles; the low flavor extraction efficiency, unpleasant odors, and poor stability of existing fruit beers, and the lack of optimization for fruit characteristics in some fermentation methods; the difficulty in adjusting the acid-sugar balance of characteristic fruits using traditional processes, resulting in a sour taste and insufficient aroma; the easy oxidation and browning of beer polyphenols without effective inhibition methods, shortening product shelf life; and the lack of customized production technology for local specialty fruits, hindering the creation of differentiated products and failing to drive the upgrading of the fruit industry in the production area.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: a Hami-style fruit-based compound fermented craft beer and its preparation method, comprising:

[0010] S1: The core ingredient is a unique fruit free from mold, supplemented with traditional beer ingredients such as yeast, malt, and hops; after crushing and pressing the fruit, impurities are removed by centrifugation and sedimentation to collect pure juice.

[0011] S2: The acidity of the fruit juice is adjusted by combining chemical and biological deacidification. First, an appropriate amount of deacidifying agent is added to the centrifuged fruit juice in multiple batches and allowed to stand. The acidity and pH value of the fruit juice are initially adjusted to be close to the suitable range for fermentation, and the precipitate is separated. Then, lactic acid bacteria are introduced into the clarified fruit juice and fermented at a suitable temperature. The acidity and flavor are further optimized by biological deacidification. At the same time, pectinase is added to the deacidified fruit juice. After circulation stirring and standing clarification, the supernatant is separated to improve the clarity of the fruit juice.

[0012] S3: Add edible sugars to the clarified juice to adjust the initial sugar content of the juice to the level required for fermentation, laying the foundation for the alcohol content and taste of the final product; then add an appropriate amount of antibacterial and color-protecting agent to the juice, let it stand for a certain period of time, and then sterilize it at a suitable temperature to kill miscellaneous bacteria to avoid affecting subsequent fermentation. After sterilization, quickly cool it to the temperature required for fermentation.

[0013] S4: Inoculate the cooled juice with a specific yeast strain that has been activated, and control the fermentation temperature to be in the low-temperature range; stir regularly during the fermentation process to ensure that the yeast and juice are in full contact, and continue fermentation until the juice sugar content drops to the desired level;

[0014] S5: After fermentation, add a compound inhibitor composed of VC and EDTA-2Na to the fermentation broth, stir evenly, and maintain it at a low temperature to inhibit the oxidation reaction of polyphenols in the fermentation broth and avoid browning during subsequent storage.

[0015] S6: The fermentation liquid treated with browning inhibition is transferred to a storage tank and aged in a preset low temperature environment. The sediment at the bottom of the tank is periodically discharged to optimize the flavor and clarity. After aging, adsorbents and enzyme preparations are added to the fermentation liquid. After standing, impurities are removed by high-precision filtration equipment. The product is then filled into sterilized containers using aseptic filling to obtain the finished product.

[0016] As a further description of the above technical solution:

[0017] The Hami specialty fruits in S1 are selected from one or more of Hami melons, grapes, jujubes, and sea buckthorn, and the specialty fruits must meet the quality requirements of high sugar content and high organic acid content.

[0018] The mixing ratio of traditional beer ingredients and specialty fruit juices is adjusted to a reasonable range according to the concentration of fruit flavor, wherein the ratio of malt to hops meets the basic flavor requirements of beer.

[0019] The yeast used is a dry yeast specifically for fruit wine, and the yeast activity must reach a high level to ensure fermentation efficiency.

[0020] As a further description of the above technical solution:

[0021] The acid-lowering agent in S2 is calcium carbonate, which should be added gradually in 2-3 batches to avoid sudden changes in local acidity.

[0022] The lactic acid bacteria are a mixed strain of Lactobacillus plantarum and Lactobacillus acidophilus, and the mixing ratio of the two strains is determined to be within a reasonable range based on the acid reduction efficiency and flavor impact.

[0023] As a further description of the above technical solution:

[0024] The edible sugar in S3 is glucose or sucrose, and the adjusted sugar content of the fruit juice must be able to support the fermentation process to produce the target alcohol content.

[0025] The antibacterial and color-protecting agent is sulfurous acid or SO2 solution;

[0026] The sterilization temperature and duration must balance sterilization effectiveness with preservation of juice flavor, avoiding prolonged high temperatures that could lead to loss of fruit aroma.

[0027] As a further description of the above technical solution:

[0028] The yeast activation process in S4 needs to be carried out in sterile water at a suitable temperature. An appropriate amount of glucose is added to the sterile water to provide nutrients. After adding the dry yeast, it is stirred to dissolve and kept warm until a large number of bubbles appear to ensure that the yeast is fully activated. The temperature range of the low-temperature fermentation needs to be determined according to the characteristics of the yeast strain to ensure normal yeast metabolism and reduce the generation of undesirable flavor substances.

[0029] As a further description of the above technical solution:

[0030] The ratio of VC to EDTA-2Na added in S5 needs to be adjusted to an appropriate range based on the volume of the fermentation broth and the content of polyphenols.

[0031] The addition of the compound inhibitor should be controlled after the fermentation broth has cooled to below 15°C to avoid high temperatures reducing the inhibitor's activity and to ensure the browning inhibition effect.

[0032] As a further description of the above technical solution:

[0033] The adsorbent in S6 is nano-sized SiO2, and the enzyme preparation is β-glucosidase. The amount of both added needs to be determined according to the impurity content and flavor requirements of the fermentation broth.

[0034] The high-precision filtration equipment must achieve a filtration accuracy sufficient to remove minute impurities and sediments, ensuring the product has a clear color.

[0035] The filling container is an aluminum can or a food-grade plastic bottle, which must be sterilized by moist heat treatment at 121°C before filling to ensure that the container is sterile.

[0036] As a further description of the above technical solution:

[0037] The settling and clarification time after pectinase treatment in S2 must be sufficient to allow the juice to fully separate into layers, ensuring that the supernatant after separation is free of obvious suspended impurities.

[0038] The low-temperature aging period in S6 needs to be adjusted according to the product's flavor requirements to ensure that the flavor substances in the fermentation liquid are fully integrated and to reduce pungent odors.

[0039] As a further description of the above technical solution:

[0040] The stirring frequency and duration of the fermentation process in S4 need to be adjusted according to the fermentation stage;

[0041] Increase the stirring frequency during the early stages of fermentation;

[0042] Reduce stirring frequency during the later stages of fermentation;

[0043] Determining the sugar content at the fermentation endpoint requires combining it with alcohol content testing to ensure that both reach the target range.

[0044] As a further description of the above technical solution:

[0045] The alcohol content of the fruit beer product is in the range of 12.0-14.0% vol, the total acid content is controlled within the range suitable for drinking, and the pH value is in the range of 3.2-3.8.

[0046] The beneficial effects achieved by the present invention using the above structure are as follows:

[0047] (1) In this invention, by combining the "chemical acid reduction + biological acid reduction" compound regulation technology with the precise sugar adjustment process, the problem of high organic acid content and low sugar content of Hami special fruits (such as sea buckthorn and jujube) is effectively overcome. First, the acidity is initially balanced by step-by-step acid reduction with calcium carbonate, and then the flavor is optimized by biological acid reduction with lactic acid bacteria. The sugar content is adjusted to the appropriate fermentation level with edible sugar. This not only avoids the problem of sourness and lack of aroma in the traditional process, but also achieves a precise balance between the natural flavor of the fruit and the mellow taste of the beer, significantly improving the palatability of the fruit beer.

[0048] (2) In this invention, a low-temperature fermentation process is adopted, which is combined with the synergistic effect of β-glucosidase and nano-sized SiO2. Compared with the existing maceration method for fruit beer production, it can not only fully release the flavor substances in the fruit and retain the natural nutrients and aroma of the fruit to the greatest extent, but also effectively inhibit the generation of unpleasant odors during fermentation. At the same time, the combination of VC and EDTA-2Na as a browning inhibitor completely solves the industry pain point of oxidative browning of polyphenols in beer, so that the product can still maintain a clear color and no obvious sedimentation within 6 months under normal storage conditions, which greatly extends the shelf life and quality stability of the product.

[0049] (3) Using specialty fruits from Hami region as core raw materials, on the one hand, it replaces some barley malt, wheat malt and other grain crops in traditional beer production, reducing the beer industry's dependence on grain resources and conforming to the national concept of resource conservation and food security; on the other hand, through customized craft brewing processes, local specialty agricultural products are transformed into high-value-added beverage products, which can directly drive the optimization of the fruit and forestry planting structure in Hami region, promote the development of supporting industries such as fruit and forestry picking, pre-processing and packaging, form a complete industrial chain of "agricultural products-processing-sales", and provide a practical path for the integration and upgrading of local agriculture and industry;

[0050] (4) The process route of the present invention covers the entire process of standardized operation, including raw material pretreatment, fermentation, aging, filtration and bottling. The equipment involved, such as crushing system, fermentation system and CIP cleaning system, are all adapted to the needs of industrial production. Through single-factor experiments and parameter optimization, a stable and controllable production process system has been formed. This system can ensure the consistency of flavor and quality of different batches of products, and can flexibly adjust the ratio of fruit raw materials according to market demand (such as mixing cantaloupe and grapes, mixing sea buckthorn and jujubes, etc.) to achieve large-scale production of multi-flavor fruit beer. This provides craft beer companies with replicable differentiated product solutions and helps them expand their market share. Attached Figure Description

[0051] Figure 1 This invention presents a composite deacidification and clarification process for a Hami-specific fruit-fermented craft beer and its preparation method.

[0052] Figure 2 This is a flowchart illustrating the linkage between sugar adjustment, sterilization, and yeast activation in a Hami-style fruit compound fermentation craft beer and its preparation method, as proposed in this invention. Detailed Implementation

[0053] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0054] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0055] To address the problems mentioned in the background art, this application provides an embodiment of a Hami-style fruit-based compound fermented craft beer and its preparation method, such as... Figures 1-2 As shown, a Hami-style fruit-based compound fermented craft beer and its preparation method include:

[0056] S1: The core ingredient is a unique fruit free from mold, supplemented with traditional beer ingredients such as yeast, malt, and hops; after crushing and pressing the fruit, impurities are removed by centrifugation and sedimentation to collect pure juice.

[0057] S2: The acidity of the fruit juice is adjusted by combining chemical and biological deacidification. First, an appropriate amount of deacidifying agent is added to the centrifuged fruit juice in multiple batches and allowed to stand. The acidity and pH value of the fruit juice are initially adjusted to be close to the suitable range for fermentation, and the precipitate is separated. Then, lactic acid bacteria are introduced into the clarified fruit juice and fermented at a suitable temperature. The acidity and flavor are further optimized by biological deacidification. At the same time, pectinase is added to the deacidified fruit juice. After circulation stirring and standing clarification, the supernatant is separated to improve the clarity of the fruit juice.

[0058] S3: Add edible sugars to the clarified juice to adjust the initial sugar content of the juice to the level required for fermentation, laying the foundation for the alcohol content and taste of the final product; then add an appropriate amount of antibacterial and color-protecting agent to the juice, let it stand for a certain period of time, and then sterilize it at a suitable temperature to kill miscellaneous bacteria to avoid affecting subsequent fermentation. After sterilization, quickly cool it to the temperature required for fermentation.

[0059] S4: Inoculate the cooled juice with a specific yeast strain that has been activated, and control the fermentation temperature to be in the low-temperature range; stir regularly during the fermentation process to ensure that the yeast and juice are in full contact, and continue fermentation until the juice sugar content drops to the desired level;

[0060] S5: After fermentation, add a compound inhibitor composed of VC and EDTA-2Na to the fermentation broth, stir evenly, and maintain it at a low temperature to inhibit the oxidation reaction of polyphenols in the fermentation broth and avoid browning during subsequent storage.

[0061] S6: The fermentation liquid treated with browning inhibition is transferred to a storage tank and aged in a preset low temperature environment. The sediment at the bottom of the tank is periodically discharged to optimize the flavor and clarity. After aging, adsorbents and enzyme preparations are added to the fermentation liquid. After standing, impurities are removed by high-precision filtration equipment. The product is then filled into sterilized containers using aseptic filling to obtain the finished product.

[0062] In this way, by combining the "chemical deacidification + biological deacidification" compound regulation technology with the precise sugar adjustment process, the raw material characteristics of Hami specialty fruits (such as sea buckthorn and jujube) with high organic acid content and low sugar content can be effectively overcome. First, calcium carbonate is used to reduce acidity step by step to initially balance the acidity. Then, lactic acid bacteria are used to biologically reduce acidity to optimize the flavor. Edible sugar is used to adjust the sugar content to the appropriate fermentation level. This not only avoids the problems of sourness and insufficient aroma in traditional processes, but also achieves a precise balance between the natural flavor of the fruit and the mellow taste of beer, significantly improving the palatability of fruit beer.

[0063] The Hami specialty fruits in S1 are selected from one or more of Hami melons, grapes, jujubes, and sea buckthorn, and the specialty fruits must meet the quality requirements of high sugar content and high organic acid content.

[0064] The mixing ratio of traditional beer ingredients and specialty fruit juices is adjusted to a reasonable range according to the concentration of fruit flavor, wherein the ratio of malt to hops meets the basic flavor requirements of beer.

[0065] The yeast used is a dry yeast specifically for fruit wine, and the yeast activity must reach a high level to ensure fermentation efficiency.

[0066] The acid-lowering agent in S2 is calcium carbonate, which should be added gradually in 2-3 batches to avoid sudden changes in local acidity.

[0067] The lactic acid bacteria are a mixed strain of Lactobacillus plantarum and Lactobacillus acidophilus, and the mixing ratio of the two strains is determined to be within a reasonable range based on the acid reduction efficiency and flavor impact.

[0068] The edible sugar in S3 is glucose or sucrose, and the adjusted sugar content of the fruit juice must be able to support the fermentation process to produce the target alcohol content.

[0069] The antibacterial and color-protecting agent is sulfurous acid or SO2 solution;

[0070] The sterilization temperature and duration must balance sterilization effectiveness with preservation of juice flavor, avoiding prolonged high temperatures that could lead to loss of fruit aroma.

[0071] The yeast activation process in S4 needs to be carried out in sterile water at a suitable temperature. An appropriate amount of glucose is added to the sterile water to provide nutrients. After adding the dry yeast, it is stirred to dissolve and kept warm until a large number of bubbles appear to ensure that the yeast is fully activated. The temperature range of the low-temperature fermentation needs to be determined according to the characteristics of the yeast strain to ensure normal yeast metabolism and reduce the generation of undesirable flavor substances.

[0072] The ratio of VC to EDTA-2Na added in S5 needs to be adjusted to an appropriate range based on the volume of the fermentation broth and the content of polyphenols.

[0073] The addition of the compound inhibitor should be controlled after the fermentation broth has cooled to below 15°C to avoid high temperatures reducing the inhibitor's activity and to ensure the browning inhibition effect.

[0074] The adsorbent in S6 is nano-sized SiO2, and the enzyme preparation is β-glucosidase. The amount of both added needs to be determined according to the impurity content and flavor requirements of the fermentation broth.

[0075] The high-precision filtration equipment must achieve a filtration accuracy sufficient to remove minute impurities and sediments, ensuring the product has a clear color.

[0076] The filling container is an aluminum can or a food-grade plastic bottle, which must be sterilized by moist heat treatment at 121°C before filling to ensure that the container is sterile.

[0077] The settling and clarification time after pectinase treatment in S2 must be sufficient to allow the juice to fully separate into layers, ensuring that the supernatant after separation is free of obvious suspended impurities.

[0078] The low-temperature aging period in S6 needs to be adjusted according to the product's flavor requirements to ensure that the flavor substances in the fermentation liquid are fully integrated and to reduce pungent odors.

[0079] The stirring frequency and duration of the fermentation process in S4 need to be adjusted according to the fermentation stage;

[0080] Increase the stirring frequency during the early stages of fermentation;

[0081] Reduce stirring frequency during the later stages of fermentation;

[0082] Determining the sugar content at the fermentation endpoint requires combining it with alcohol content testing to ensure that both reach the target range.

[0083] The alcohol content of the fruit beer product is in the range of 12.0-14.0% vol, the total acid content is controlled within the range suitable for drinking, and the pH value is in the range of 3.2-3.8.

[0084] To better understand the working process of the Hami-style fruit compound fermentation craft beer and its preparation method according to the embodiments of this application, please refer to... Figures 1-2 The following is a specific embodiment:

[0085] I. Raw Material Selection and Matching

[0086] Fresh sea buckthorn berries (16% sugar content, 9g / 100g organic acid content) at 88% maturity and seedless white grapes (18% sugar content, 6g / 100g organic acid content) at 90% maturity from the Hami region were selected and mixed at a mass ratio of 1:2 as the core fruit raw materials. The complementary acid and sugar properties of the two fruits were utilized to reduce the impact of excessive organic acid content in a single fruit. In the traditional beer raw materials, malt and hops were mixed at a mass ratio of 100:0.5, and fruit wine-specific dry yeast with an activity ≥10^9 CFU / g was selected to ensure fermentation efficiency and flavor development.

[0087] II. Preprocessing Stage

[0088] Fruit pretreatment: Wash the mixed fruits with 22℃ water for 6 minutes. Retain the peel of sea buckthorn (rich in flavonoid nutrients). Peel and destem the grapes. Crush and press the juice using a screw press with a pressure of 0.4MPa, achieving a juice extraction rate of 86%. Process the juice with a centrifuge at 4000r / min for 20 minutes to remove pulp residue and coarse fiber, obtaining a pure compound juice with a turbidity of 4NTU. Store the juice temporarily in a sterile storage tank at 10℃ to prevent oxidation and spoilage.

[0089] Traditional raw material pretreatment: Malt is crushed and passed through a 20-mesh sieve (92% sieve pass rate), and hops are crushed and sealed for later use; yeast activation is started simultaneously by adding 3% glucose to sterile water at 38℃, adding 0.1% dry yeast and stirring to dissolve, and keeping warm for 45 minutes until a large number of uniform bubbles appear (yeast activity reaches 1.2×10^9 CFU / mL), and temporarily storing in a light-protected environment at 21℃ to ensure that the yeast is in an active state.

[0090] III. Acid-Sugar Adjustment and Clarification

[0091] Compound acid reduction: First, a 12% calcium carbonate solution was prepared and added to the compound fruit juice in three separate additions (each addition 2 hours apart). The first addition was 30% of the total amount, with a stirring speed of 70 r / min. After standing for 2 hours, the pH was measured to be 3.9. The second addition was 70% of the total amount, and after standing for 4 hours, the juice was filtered to remove the calcium carbonate precipitate. At this point, the pH of the juice was stable at 3.5. Subsequently, Lactobacillus plantarum and Lactobacillus acidophilus (mixed ratio 1:1.5) were inoculated at an inoculum size of 0.1%, and fermented at 29℃ for 10 hours. Through the metabolism and decomposition of some organic acids by lactic acid bacteria, the total acid of the juice was finally adjusted to 12 g / L (calculated as lactic acid), while lactic acid flavor substances were generated, optimizing the taste harmony.

[0092] Pectinase clarification: Add pectinase with an enzyme activity of 3000 U / g to the deacidified juice at a rate of 80g / ton of juice. Circulate and stir at 50℃ for 1.5 hours to allow the pectinase to fully decompose the pectin in the juice and disrupt its colloidal stability. Then let it stand at 21℃ for 10 hours. Separate the supernatant by siphoning to obtain a clarified compound juice with a turbidity of 1.8 NTU, thus avoiding precipitation during subsequent fermentation.

[0093] IV. Sugar Adjustment, Sterilization, and Yeast Synergy

[0094] Precise sugar adjustment: The initial sugar content of the clarified juice was 17%. A mixed sugar solution of glucose and sucrose (mass ratio 2:1) was added in three gradients (stirring for 15 minutes after each addition) to finally adjust the sugar content of the juice to 24%, providing sufficient carbon source for the target alcohol content to be generated during the fermentation process.

[0095] Antibacterial, color-protecting, and sterilization: 10% sulfurous acid solution was added to the sugar-adjusted juice to achieve a SO2 residue of 60 mg / L. The juice was then left to stand in the dark for 10 hours to inhibit the growth of miscellaneous bacteria and protect the natural color of the fruit. Subsequently, the juice was sterilized in stages using a plate heat exchanger. First, the juice was heated to 60℃ and held for 10 minutes, then heated to 75℃ and held for 30 minutes, and finally cooled to 60℃ and held for 10 minutes. After sterilization, the juice was rapidly cooled to 27℃ (cooling rate 4℃ / min). The total bacterial count was found to be 8 CFU / mL, meeting the requirements for aseptic fermentation.

[0096] Yeast inoculation linkage: After confirming that the activated yeast activity meets the standard, slowly add the yeast liquid to the cooled juice at a ratio of 0.12% and mix evenly at a stirring speed of 80r / min. This allows the yeast to quickly adapt to the suitable temperature and sugar content environment, laying the foundation for the subsequent fermentation start-up.

[0097] V. Dynamic Control of Low-Temperature Fermentation

[0098] Staged fermentation control: In the initial stage of fermentation (0-24h, adaptation period), the temperature is controlled at 27℃, and the stirring frequency is 3 times / h (10min each time) to allow the yeast to quickly adapt to the juice environment and multiply. The yeast count increases from the initial 1.2×10^9 CFU / mL to 5.8×10^8 CFU / mL. In the middle stage of fermentation (24-72h, logarithmic stage), the temperature is raised to 28℃, and the stirring frequency is increased to 5 times / h (15min each time) to promote yeast metabolism and rapidly decompose sugars to produce alcohol and flavor substances. At this time, the sugar content decreases from 24% to 10%, and the alcohol content increases to 8% vol. In the later stage of fermentation (72-168h, stabilization period), the temperature is lowered to 26℃, and the stirring frequency is reduced to 2 times / h (8min each time) to reduce oxidation reactions and allow flavor substances to fully integrate. Finally, the sugar content decreases to 4%, and the alcohol content reaches 13.5% vol.

[0099] Real-time feedback adjustment: Sugar content, alcohol content and pH are measured every 4 hours during fermentation. When it is found that the sugar content decrease rate is only 0.3 Bx / day after 96 hours of fermentation, the stirring frequency is increased to 3 times / hour and the stirring time is extended to 10 minutes each time. After 24 hours, the sugar content decrease rate recovers to 0.6 Bx / day, ensuring sufficient fermentation.

[0100] VI. Browning Inhibition and Quality Stability

[0101] After fermentation is terminated, the fermentation broth is cooled to 14℃, and a compound inhibitor is added at a ratio of 0.08% VC and 0.03% EDTA-2Na. After stirring evenly, the mixture is kept at 12℃ for 3 hours. The reducing properties of VC and the chelating effect of EDTA-2Na work together to inhibit the contact between polyphenols and oxygen in the fermentation broth, thus preventing oxidative browning. At the same time, the amount of inhibitor added is controlled within a range that does not affect the flavor of the product, ensuring that the fruit beer retains the natural aroma of sea buckthorn and grapes.

[0102] VII. Aged Bottling and Quality Closed Loop

[0103] Mature aging: The fermentation liquid after browning inhibition is transferred to a storage tank that has been cleaned with CIP, sterilized at 121℃ for 30 minutes and cooled to 3℃. It is aged at 4℃ for 25 days. During this period, the sediment at the bottom of the tank (mainly yeast mud and protein sediment) is drained every 5 days to promote the integration of flavor substances and reduce the pungent odor of the product.

[0104] Purification and Filtration: After aging, 0.2 g / L of nano-sized SiO2 and 20 g / ton of β-glucosidase are added to the fermentation liquid. After stirring evenly, it is allowed to stand for 6 hours. The nano-sized SiO2 adsorbs tiny impurities and some proteins in the fermentation liquid, and the β-glucosidase decomposes residual pectin and glycosides, improving the flavor release efficiency. Then, it is filtered through a plate and frame filter with a precision of 0.3 μm to obtain a clear fruit beer base liquid.

[0105] Aseptic filling and testing: The cans were sterilized by moist heat at 121℃ for 18 minutes. The fruit beer base liquid was then filled into the containers using aseptic filling equipment. After filling, the cans were inspected by light, and unqualified products with impurities or insufficient filling volume were removed. The final product test showed that the alcohol content was 13.5% vol, the total acid was 8g / L (calculated as lactic acid), the pH was 3.6, the color was golden yellow, the aroma of sea buckthorn and grape was strong, there was no unpleasant odor, and there was no browning or precipitation after 6 months of normal storage.

[0106] Summary of core working principles

[0107] This application employs a comprehensive, collaborative design across the entire process: "Specialty Fruit Compound Ratio → Compound Acid Reduction (Chemical + Biological) → Precise Sugar Adjustment → Low-Temperature Staged Fermentation → Compound Browning Inhibitor → Purification and Aging." This approach specifically addresses technical challenges such as high acidity and low sugar content in fruits, unstable fermentation, and susceptibility to browning. Specifically, the compound acid reduction technology optimizes both acidity and flavor; low-temperature staged fermentation ensures a balance between alcohol content and flavor; and compound inhibitors and purification filtration technology enhance product stability. The close integration of each process step, through precise matching of raw material characteristics and process parameters, ultimately produces high-quality, differentiated compound fermented craft fruit beer.

[0108] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0109] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0110] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A Hami specialty fruit compound fermented craft fruit beer and a preparation method thereof, characterized in that, Comprise: S1: No mildew characteristic fruit as the core raw material, supplemented by yeast, malt, hops and other traditional beer raw materials; after crushing and squeezing treatment of the characteristic fruit, remove impurities by centrifugal sedimentation separation, collect pure fruit juice; S2: The chemical and biological acid reduction combined method is used to adjust the acidity of the fruit juice; add appropriate amount of acid reducing agent to the centrifuged fruit juice, add gradually for several times and stand, initially adjust the acidity and pH value of the fruit juice to the appropriate range for fermentation, and separate the precipitate; then inoculate lactic acid bacteria into the clarified fruit juice, ferment at appropriate temperature, further optimize the acidity and flavor by biological acid reduction; at the same time, add pectinase to the fruit juice after acid reduction, clarify by circulating stirring and standing, separate the supernatant to improve the clarity of the fruit juice; S3: Add edible sugar to the clarified fruit juice to adjust the initial sugar content of the fruit juice to the level required for fermentation, lay the foundation for the alcohol content and taste of the final product; then add appropriate amount of bacteriostatic color protection agent to the fruit juice, stand for a certain period of time, and then sterilize at appropriate temperature to kill bacteria to avoid affecting the subsequent fermentation; cool quickly to the required fermentation temperature after sterilization; S4: Inoculate the cooled fruit juice into the activated specific yeast strain, control the fermentation temperature in the low temperature range; stir regularly during fermentation to ensure that the yeast and fruit juice are in full contact, and continue to ferment until the sugar content of the fruit juice decreases to the desired level; S5: After the fermentation is completed, add a compound inhibitor composed of VC and EDTA-2Na to the fermentation broth, stir uniformly and maintain in a low temperature environment to inhibit the oxidation reaction of polyphenolic substances in the fermentation broth and avoid browning during subsequent storage; S6: Transfer the fermentation broth treated by browning inhibition to the wine storage tank, age in the pre-set low temperature environment, and regularly discharge the sediment at the bottom of the tank to optimize the flavor and clarity; after aging, add adsorbent and enzyme preparation to the fermentation broth, stand, and then remove impurities by high-precision filtration equipment; use sterile filling method to fill the product into sterilized containers to obtain the finished product.

2. The Hami characteristic fruit compound fermented fruit beer according to claim 1 and the preparation method thereof, characterized in that: The Hami characteristic fruit in S1 is selected from one or more mixtures of Hami melon, grape, jujube and sea buckthorn, and the characteristic fruit meets the quality requirements of high sugar content and organic acid content; The mixing ratio of the traditional beer raw material and the characteristic fruit juice is adjusted to a reasonable range according to the fruit flavor concentration, and the ratio of malt to hops meets the basic flavor requirements of beer; The yeast is selected from fruit wine special dry yeast, and the yeast activity needs to reach a high level to ensure the fermentation efficiency.

3. The Hami characteristic fruit compound fermented fruit beer according to claim 2 and the preparation method thereof, characterized in that: The acid reducing agent in S2 is calcium carbonate, which needs to be added gradually in 2-3 times to avoid sudden change of local acidity; The lactic acid bacteria are mixed strains of Lactobacillus plantarum and Lactobacillus acidophilus, and the mixing ratio of the two strains is determined in a reasonable range according to the acid reduction efficiency and flavor influence.

4. The Hami characteristic fruit compound fermented fruit beer according to claim 3 and the preparation method thereof, characterized in that: The edible sugar in S3 is glucose or sucrose, and the adjusted sugar content of the fruit juice should be able to support the production of target alcohol content during fermentation; The bacteriostatic color protection agent is sulfurous acid or SO2 solution; The sterilization temperature and time should take into account the sterilization effect and the retention of fruit juice flavor, avoiding the loss of fruit flavor caused by long-term high temperature.

5. The Hami characteristic fruit compound fermented craft beer and its preparation method according to claim 4, characterized in that, The yeast activation treatment in S4 needs to be carried out in sterile water at a suitable temperature, and a suitable amount of glucose is added to the sterile water to provide nutrition. After adding dry yeast, stir to dissolve and keep warm until a large amount of bubbles appear, to ensure that the yeast is fully activated. The temperature range of low-temperature fermentation needs to be determined according to the characteristics of the yeast strain, to ensure normal metabolism of the yeast and reduce the generation of undesirable flavor substances.

6. The Hami characteristic fruit compound fermented craft beer and its preparation method according to claim 5, characterized in that, The addition ratio of VC and EDTA-2Na in S5 needs to be adjusted to an appropriate range according to the volume of the fermentation liquid and the content of polyphenolic substances; The addition time of the compound inhibitor needs to be controlled after the fermentation liquid is cooled to below 15℃, to avoid the reduction of inhibitor activity at high temperature and ensure the inhibition effect of browning.

7. The Hami characteristic fruit compound fermented craft beer and its preparation method according to claim 6, characterized in that, The adsorbent in S6 is nano-sized SiO2, and the enzyme preparation is β-glucosidase. The addition amount of both needs to be determined according to the impurity content and flavor demand of the fermentation liquid; The filtration precision of the high-precision filtration equipment needs to reach a level that can remove small impurities and precipitates, to ensure the clear color of the product; The filling container is a pop-top can or a food-grade plastic bottle, which needs to be treated with 121℃ moist heat sterilization before filling, to ensure that the container is sterile.

8. The Hami characteristic fruit compound fermented craft beer and its preparation method according to claim 7, characterized in that, The standing and clarification time after pectinase treatment in S2 needs to meet the requirement of sufficient stratification of the fruit juice, to ensure that the supernatant after separation has no obvious suspended impurities; The low-temperature aging period in S6 needs to be adjusted according to the flavor demand of the product, to ensure that the flavor substances in the fermentation liquid are fully integrated and the irritating odor is reduced.

9. The Hami characteristic fruit compound fermented craft beer and its preparation method according to claim 8, characterized in that, The stirring frequency and time of the fermentation process in S4 need to be adjusted according to the fermentation stage; Increase the stirring frequency in the early stage of fermentation; Reduce the stirring frequency in the later stage of fermentation; The sugar content judgment at the end of fermentation needs to be combined with alcohol content detection, to ensure that both reach the target range.

10. The Hami characteristic fruit compound fermented craft beer and its preparation method according to claim 9, characterized in that, The alcohol content of the fruit beer product is in the range of 12.0-14.0%vol, the total acid content is controlled in the range of suitable drinking, and the pH value is in the range of 3.2-3.8.

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