A mixed fermentation pomace composite wine and a preparation method thereof

Abstract

The application discloses a kind of mixed fermentation pomace composite wine and preparation method thereof, and it is related to the technical field of brewing wine.The present application uses the technical system of "raw material scientific compounding, ion chelation enzymolysis, compound strain fermentation" mutual coordination, based on the brewing method of pomace and high starch cereal composite substrate, by metal ion and complex enzymolysis and compound strain coupling, a new type of multi-enzyme-multiple bacteria synergistic fermentation system is constructed, the efficient conversion of pomace and cereal substrate is realized, not only significantly improves the alcohol fermentation efficiency and alcohol yield, but also improves the taste and flavor complexity of wine body, provides an effective technical solution for the high-value utilization of pomace resources.

Description

Technical Field

[0001] This invention relates to the field of brewing technology, and in particular to a mixed-culture fermented fruit pomace compound wine and its preparation method. Background Technology

[0002] Brewing, as a traditional biotransformation method, provides a feasible path for the efficient utilization of fruit pomace, but its technical system still needs systematic optimization.

[0003] Currently, brewing processes using fruit pomace as raw material still face a series of common technical challenges:

[0004] Low utilization rate is caused by limitations in the structure and composition of raw materials: the pomace contains high levels of structural polysaccharides such as pectin and cellulose, and has dense cell walls. Traditional crushing and single enzyme treatment are insufficient to fully release the effective components, resulting in a low rate of fermentable sugar dissolution, which directly affects the efficiency of subsequent fermentation and the yield of alcohol.

[0005] The fermentation substrate is nutritionally unbalanced, resulting in low alcohol yield and alcohol content: the carbon source of fruit pomace is mainly complex polysaccharides, with insufficient available sugars, and a relative lack of microbial growth factors such as nitrogen sources and minerals, which leads to slow fermentation start-up, incomplete metabolism, and a significantly lower alcohol yield than that of grain raw materials.

[0006] Poor flavor harmony and stability: The high content of polyphenols and organic acids in the pomace can easily cause a noticeable astringency and an imbalance between acidity and astringency in the wine. At the same time, insufficient release of aroma precursors and simple metabolites during fermentation result in a simple aroma structure and a rough taste in the finished wine.

[0007] Insufficient retention and activity enhancement of functional components: Traditional fermentation processes (enzymatic hydrolysis-single-strain fermentation-distillation-blending) have limited ability to protect and transform functional components such as polyphenols and flavonoids. Active substances are easily degraded and lost during fermentation, resulting in a lack of prominent functionality in the finished wine and failing to fully realize the health benefits of fruit pomace raw materials. Summary of the Invention

[0008] In response to the problems of low raw material utilization, low alcohol yield, poor flavor complexity, uncoordinated astringency and acidity, and insufficient stability and functionality of existing fruit pomace wines on the market, this patent provides a mixed-culture fermented fruit pomace compound wine and its preparation method.

[0009] This application scientifically combines fruit pomace and grains to design a highly efficient synergistic dissolution and conversion system, effectively combining high-phenolic acid fruit pomace with high-starch grain products, reducing the toxicity of fermentation byproducts, and effectively increasing the product's alcohol yield; through complex enzymatic coupling... , Using metal ion chelation technology, enzyme activity characteristics are precisely controlled to achieve optimal enzymatic hydrolysis, enhancing hydrolysis efficiency and releasing more fermentable sugars and aromatic precursors, thus achieving efficient utilization of pomace resources. Simultaneously, fermentation with compound microbial strains stimulates the fermentation metabolic potential of microorganisms, thereby achieving efficient dissolution and functional transformation of active ingredients. Combined with targeted fermentation controlled by microbial metabolism, the functional characteristics and aroma complexity of the wine are enhanced. Finally, the resulting mash is further distilled and aged to obtain a higher quality, more functional, and more harmonious pomace-based compound wine product.

[0010] In a first aspect, this application provides a method for preparing a mixed-culture fermented fruit pomace compound wine, comprising the following preparation steps:

[0011] S1 Fruit pomace treatment: Take the fruit pomace, dehydrate it to a moisture content of 55%-60%, and obtain fruit pomace slurry; add 0.05-0.3 g / L of [unspecified ingredient] to the fruit pomace slurry. and / or Metal ion solution; then add cell wall degrading enzyme, adjust pH to 4.8-5.2, and slowly stir at 35-45 ℃ to carry out enzymatic hydrolysis to promote the degradation of pectin and cellulose and release soluble sugars and aromatic precursors;

[0012] S2 Grain Processing: The grains undergo a moistening process to reduce the moisture content to 30%-35%. After moistening, the grains are steamed and soaked in hot water to fully gelatinize the starch, achieving a flowering rate of 90%-98%. The pH is adjusted to 4-5, and glucoamylase is added at 30-55 ℃ for enzymatic hydrolysis to achieve starch hydrolysis and saccharification. Then, 5-12 w / w% of steamed rice husks are added based on the total raw material mass.

[0013] S3 Inoculation with Compound Microbial Strains: Fruit pomace and grains are mixed to form a compound mixture, and a compound novel yeast is added. The compound novel yeast includes at least brewing yeast, and further includes at least one of Rhizopus, lactic acid bacteria and / or aromatic yeast.

[0014] S4 fermentation process: Fermentation includes an aerobic stage and an anaerobic stage in sequence.

[0015] Aerobic stage: After mixing the raw materials, pile them up for fermentation at a temperature of 24-38 ℃ for 12-48 h.

[0016] Anaerobic stage: After the material is cooled to 25-28 ℃, it is placed in a sealed tank and anaerobic fermentation is carried out for 20-50 days;

[0017] Early-stage aromatic yeasts are active, promoting the production of esters and floral and fruity aromas; in the middle and later stages, brewer's yeast dominates the ethanol conversion, ensuring a stable increase in alcohol content; lactic acid bacteria work together to maintain pH balance and impart a smooth taste.

[0018] S5 Distillation and Aging: After fermentation, distillation and aging are carried out in sequence; the aging temperature is controlled at 15-20 ℃, the humidity is 70-80%, and the aging period is 6-24 months.

[0019] Preferably, during the aerobic phase, saccharification and polysaccharide degradation are significant, and aromatic substances are gradually released, while spraying 0.05–0.2 g / L. Solution regulates microbial metabolic activities.

[0020] Furthermore, in step S1, Addition amount: 0.1–0.3 g / L Add 0.05–0.2 g / L.

[0021] Furthermore, in step S1, the enzymatic hydrolysis time is 90-240 min.

[0022] Furthermore, in step S1, the cell wall degrading enzyme includes pectinase and / or cellulase; the amount of the cell wall degrading enzyme used, based on the dry weight of the pomace, is 100-300 U / g.

[0023] Furthermore, in step S2, after the grains are gelatinized and before adding the bran, the pH is adjusted to 4-5, and glucoamylase (150-200 U / g, based on the dry weight of the grains) is added at 30-50℃, while stirring is maintained for 0.5-3 hours for enzymatic hydrolysis.

[0024] Furthermore, in step S2, 7-10 w / w% of steamed rice husks are added based on the total raw material mass.

[0025] Furthermore, in step S3, the compound mixture contains fruit pomace and grains in a mass ratio of 30-70:70-30; the grains include any one or a combination of sorghum, glutinous rice, corn, barley, and wheat; the apple pomace includes any one or a combination of fruit pomace, grape pomace, and pear pomace.

[0026] Furthermore, in step S3, the temperature of the compound mixture is 20-35 ℃.

[0027] Furthermore, in step S3, the amount of the novel compound yeast is 0.1-0.4% w / w based on the weight of the compound mixture; the novel compound yeast includes at least brewing yeast, and further includes at least one of Rhizopus, lactic acid bacteria and / or aromatic yeast.

[0028] Preferably, the novel compound yeast, by weight, comprises a combination of 0.05% w / w Rhizopus, 0.1% w / w Saccharomyces cerevisiae, 0.05% w / w Lactobacillus plantarum, and 0.02% w / w Metschnikowia pulcherrima.

[0029] Preferably, in step S4, 0.005-0.2 g / L is sprayed simultaneously during the aerobic stage. Solution regulates microbial metabolic activities.

[0030] Preferably, in step S5, during the distillation step, the wine is collected in segments, and the heads and tails are removed; the condensation temperature is controlled at 30 ℃.

[0031] Secondly, this application provides a wine mash or mixed-culture fermented fruit pomace compound wine obtained using the preparation method of this application.

[0032] Beneficial effects: 1. This application adopts a technical system that combines "scientific compounding of raw materials, ion chelation enzymatic hydrolysis, and fermentation of compound strains" in a synergistic manner;

[0033] A brewing method based on a complex substrate of fruit pomace and high-starch grains, wherein... , The coupling of metal ion enzymatic hydrolysis and fermentation by composite strains achieves optimal matching between enzyme activity and strain metabolism, thereby improving saccharification efficiency, alcoholic fermentation efficiency, and the complexity of the wine's flavor. In this method, metal ions form complexes with pectin and polysaccharide structures in the pomace-grain substrate, optimizing the polysaccharide spatial structure and enhancing the activity of enzymes such as pectinase, cellulase, and amylase. Simultaneously, it helps stabilize the pH and redox state of the system, providing a suitable environment for the metabolism of yeast, lactic acid bacteria, and Rhizopus strains. Specifically, It can enhance the activity of pectinase and cellulase, while stabilizing the cell structure of yeast and lactic acid bacteria. As a cofactor for various saccharifying enzymes and proteases, it can promote the release of fermentable sugars and amino acids and regulate the metabolic activity of yeast and lactic acid bacteria.

[0034] Furthermore, the composite bacterial strain system employed includes yeast, Rhizopus, and lactic acid bacteria. Saccharomyces cerevisiae primarily produces ethanol, Rhizopus secretes saccharifying enzymes to degrade starch and release fermentable sugars, lactic acid bacteria maintain a low pH while producing lactic acid to improve the wine's mouthfeel, and aromatic yeasts release various esters, alcohols, and aromatic precursors to enhance the complexity of the wine's aroma. This is achieved through control... , The amount, timing, and concentration range of the added strains can be carefully controlled to achieve a synergistic stabilizing effect during the staged fermentation process, thereby simultaneously improving fermentation efficiency, alcohol yield, and the sensory quality of the wine. Optimal conditions are... Addition amount: 0.1–0.3 g / L The addition amount is 0.05–0.2 g / L, the enzymatic hydrolysis temperature is 35–45°C, the pH value is 4.8–5.2, and the metal ions are added in the middle of the enzymatic hydrolysis or the early stage of fermentation to ensure that the synergistic effect of the enzyme-metal-strain system reaches the best effect.

[0035] This invention constructs a novel multi-enzyme-multi-strain synergistic fermentation system by coupling metal ions with complex enzymatic hydrolysis and complex bacterial strains, achieving efficient conversion of fruit pomace and grain substrates. This not only significantly improves alcohol fermentation efficiency and alcohol yield, but also enhances the taste and flavor complexity of the liquor, providing an effective technical solution for the high-value utilization of fruit pomace resources.

[0036] 2. Rice husks have a porous structure and a certain cation exchange capacity. During the steaming process, more active sites will form on its surface, when it contains... After the fruit pomace slurry containing metal ions is mixed with rice husks They can be adsorbed onto the surface and pores of rice husks. During the long solid-state fermentation process, these adsorbed ions can be slowly released, playing a long-term role in pH buffering and ion stabilization, which helps maintain the stable microenvironment required by fermenting microorganisms (yeast, lactic acid bacteria, etc.).

[0037] It acts as a cofactor or stabilizer for enzymes (such as pectinase and esterase), helping to maintain their activity. The aerobic-microaerobic gradient environment provided by rice husks is one of the important environmental conditions required for yeast and ester-producing yeasts (such as Metschnikowia pulcherrima) to metabolize and produce ester aromatic substances. The combination of the two provides a better platform for yeast metabolism, jointly promoting the generation of flavor compounds. Attached Figure Description

[0038] Figure 1 This is a radar image showing the results of electronic nose measurement of distilled spirits obtained in the embodiments of the present invention;

[0039] Figure 2 This is a graph showing the yield of distilled spirits produced using the methods described in the examples. Detailed Implementation

[0040] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] An example of a method for preparing a mixed-culture fermented fruit pomace compound wine includes the following steps:

[0042] S1 Fruit Pomace Treatment: Select apple pomace, grape pomace, pear pomace, etc., remove large pieces of peel and impurities, then crush (particle size ≤ 5mm), and dehydrate appropriately to a moisture content of 55%-60%. Before enzymatic hydrolysis, add 0.05-0.3 g / L of [a specific ingredient / component] to the pomace slurry. and / or Add a metal ion solution and stir for 10 min to ensure ion dispersion. Then add a cell wall degrading enzyme (100-300 U / g based on the dry weight of the fruit pomace), adjust the pH to 4.8-5.2, and slowly stir at 35-45 ℃ for 60-300 min to promote the degradation of pectin and cellulose and release soluble sugars and aromatic precursors.

[0043] S2 Grain Processing: Select grains such as sorghum, glutinous rice, corn, barley, and wheat. After washing and removing impurities, the grains undergo a moistening process to achieve a moisture content of 30%-35%. The moistened grains are then subjected to two rounds of steaming and hot water soaking to ensure complete starch gelatinization and a flowering rate of over 95%. The pH is adjusted to 4-5, and glucoamylase (150-200 U / g, based on grain dry weight) is added at 30-55℃. Enzymatic hydrolysis is carried out for 0.5-3 hours with stirring to achieve starch hydrolysis and saccharification. After steaming, bran husks (5-12%, w / w, based on total raw material mass) that have been steamed for 30-60 minutes are added as an auxiliary material to enhance aeration and, in synergy with metal ions, improve yeast fermentation and release flavor compounds.

[0044] S3 Inoculation with Compound Microbial Culture: The compound raw materials, cooled to 28 ℃, are mixed with fruit pomace and grains at a mass ratio of 30-70:30-70. A novel compound yeast is added, preferably containing 0.05% w / w Rhizopus, 0.1% w / w Saccharomyces cerevisiae, 0.05% w / w Lactobacillus plantarum, and 0.02% w / w Metschnikowia pulcherrima. This compound microbial community effectively regulates the efficient hydrolysis of starch, stable alcohol production, release of aromatic substances, and the dynamic balance of organic acids through the synergistic effects of multiple enzyme systems and metabolic pathways, thereby optimizing flavor and increasing yield.

[0045] S4 fermentation process:

[0046] (1) Stack fermentation (aerobic stage): After mixing the raw materials, stack them for fermentation. The initial temperature is above 24 ℃, and the fermentation temperature naturally increases with metabolism but does not exceed 38 ℃. The aerobic fermentation time is 12-48 h. During this stage, saccharification and polysaccharide degradation are significant, and aromatic substances are gradually released. 0.005-0.2 g / L can be sprayed simultaneously. Solution regulates microbial metabolic activities.

[0047] (2) Primary fermentation (anaerobic stage): After the material is cooled to 25-28 ℃, it is placed in a sealed tank and anaerobic fermentation is carried out for 20-50 days. In the early stage, aromatic yeasts are active, promoting the production of esters and floral and fruity aromas; in the middle and late stages, brewer's yeast takes the lead in completing the ethanol conversion, ensuring a stable increase in alcohol content; lactic acid bacteria work together to maintain pH balance and give it a mellow taste.

[0048] (3) The criteria for determining the completion of fermentation are that the mash has a strong aroma, and when squeezed by hand, a hollow shell appears with a small amount of liquid overflowing.

[0049] S5 Distillation and Aging: After primary fermentation, the spirit is distilled in fractions, removing the heads and tails while retaining the characteristic flavor compounds concentrated in the middle fraction. The condensation temperature is controlled below 30°C to preserve aroma. The resulting spirit requires aging to improve stability and flavor harmony. Aging is performed in oak barrels at 15-20°C and 70-80% humidity for 6-24 months, during which esterification and aromatic stabilization occur, ultimately yielding a smooth-bodied, complex pomace wine.

[0050] By scientifically blending fruit pomace and grains, pre-treatment with ion chelation and enzymatic hydrolysis, synergistic fermentation with multiple strains of microorganisms, and staged distillation and aging, this invention not only significantly improves the utilization rate of recalcitrant components in fruit pomace and the complexity of the wine's flavor, but also enhances the sensory quality and flavor complexity of the product, thus meeting the development needs of high-quality fruit wine.

[0051] Example 1, a method for preparing a mixed-strain fermented fruit pomace compound wine - single-strain fermentation:

[0052] The fermentation of the fruit pomace and sorghum blend was carried out using a single yeast strain, *Saccharomyces cerevisiae*. This example visually reflects the utilization efficiency of the fermentable sugars and sorghum starch provided by the fruit pomace in the blend during enzymatic hydrolysis and fermentation, and evaluates their contribution to alcohol production and flavor formation.

[0053] The preparation process includes the following:

[0054] (1) Fruit pomace treatment: Select apple pomace, remove impurities and crush (particle size ≤ 5 mm), and dehydrate appropriately to a moisture content of 58%. Add pectinase (200 U / g, based on dry weight of pomace) and cellulase (100 U / g, based on dry weight of pomace) for enzymatic hydrolysis, adjust the pH to 5.0, and slowly stir and hydrolyze for 90 min at 48 ℃.

[0055] (2) Grain processing: Selected sorghum, washed and cleaned to remove impurities, and moistened to a moisture content of 32%. It was steamed twice (40 min each time) and soaked in 85 ℃ hot water for 30 min to fully gelatinize the starch and achieve a flowering rate of 95%. Food-grade citric acid was added dropwise to the gelatinized grain slurry under stirring conditions to adjust the pH to 5.0. 150 U / g of glucoamylase based on the dry weight of the grain was added at 45 ℃ for 1 h to achieve starch hydrolysis and saccharification. After steaming the bran for 40 min, 8 w / w% of the steamed bran was added based on the total raw material mass.

[0056] (3) Inoculation of strains: The fruit pomace treated by S1 and the grain treated by S2 were mixed at a mass ratio of 50:50 to form a compound mixture. The mixture was cooled to 28°C and then the activated brewing yeast (Saccharomyces cerevisiae) was evenly sprinkled in at an inoculation amount of 0.1% w / w. After being evenly mixed, the mixture was put into the fermentation stage.

[0057] (4) Fermentation: After the raw materials and yeast are evenly mixed, fermentation is carried out. Brewing yeast is added and pile fermentation (aerobic stage) is carried out at a temperature of 32 ℃. The aerobic fermentation time is 24 h. After the aerobic fermentation is completed, the temperature is controlled at 30 ℃ and the anaerobic fermentation is carried out for 30 days.

[0058] (5) Distillation: After the primary fermentation is completed, the wine is distilled in stages to remove the heads and tails, retaining the middle fraction. The condensation temperature is controlled at 4 ℃. The resulting wine is aged in oak barrels at a temperature of 20 ℃ and a humidity of 75% for 18 months to achieve esterification and the stabilization of aromatic substances.

[0059] Example 2: A method for preparing a mixed-strain fermented fruit pomace compound wine - fermentation with compound strains:

[0060] This embodiment further blends grains and fruit pomace, and introduces mixed strains such as lactic acid bacteria, Rhizopus, and aromatic yeasts to synergistically ferment with brewing yeast, in order to increase the yield and alcohol content, enrich the aroma and flavor layers of the wine, and thus obtain a fruit pomace blended wine of superior quality.

[0061] (1) Fruit pomace treatment: Select apple pomace, remove impurities and crush (particle size ≤ 5 mm), and dehydrate appropriately to a moisture content of 58%. Add pectinase (200 U / g, based on dry weight of pomace) and cellulase (100 U / g, based on dry weight of pomace) for enzymatic hydrolysis, adjust the pH to 5.0, and slowly stir and hydrolyze for 90 min at 48 ℃.

[0062] (2) Grain processing: Selected sorghum, washed and cleaned to remove impurities, and moistened to a moisture content of 32%. It was steamed twice (40 min each time) and soaked in 85 ℃ hot water for 30 min to fully gelatinize the starch and achieve a flowering rate of 95%. Food-grade citric acid was added dropwise to the gelatinized grain slurry under stirring conditions to adjust the pH to 5.0. 150 U / g of glucoamylase based on the dry weight of the grain was added at 45 ℃ for 1 h to achieve starch hydrolysis and saccharification. After steaming the bran for 40 min, 8 w / w% of the steamed bran was added based on the total raw material mass.

[0063] (3) Inoculation with compound microorganisms: The fruit pomace treated by S1 and the grain treated by S2 are mixed at a mass ratio of 50:50 to form a compound mixture. The mixture is cooled to 28 ℃ and then evenly sprinkled with compound new type of yeast. The inoculation amounts are: 0.05% w / w Rhizopus, 0.1% w / w Saccharomyces cerevisiae, 0.05% w / w Lactic acid bacteria, and 0.02% w / w Aromatic yeast (Metschnikowia pulcherrima). Fermentation is started.

[0064] (4) Fermentation: Mix the fruit pomace with the cooked grains in proportion, add the compound new type of yeast, and carry out pile fermentation (aerobic stage) at 32 ℃ for 24 h. After the aerobic fermentation is completed, control the temperature at 30 ℃ for anaerobic fermentation for 30 days.

[0065] (5) Distillation: After the primary fermentation is completed, the wine is distilled in stages to remove the heads and tails, retaining the middle fraction. The condensation temperature is controlled below 4 ℃. The resulting wine is aged in oak barrels at a temperature of 20 ℃ and a humidity of 75% for 18 months to achieve esterification and stabilization of aromatic substances, thus obtaining a mixed-strain fermented pomace complex wine. Through scientific blending of pomace and grains, ion chelation and enzymatic pretreatment, multi-strain synergistic fermentation, and staged distillation and aging, the utilization rate of recalcitrant components in the pomace and the complexity of the wine's flavor are improved.

[0066] Example 3: A method for preparing a mixed-culture fermented fruit pomace compound wine - ion chelation enzymatic hydrolysis single-strain fermentation:

[0067] Example 3, based on the single-strain fermentation of Example 1, further introduces... , The metal ion chelation enzymatic hydrolysis technology utilizes metal ions to form complexes with the polysaccharide structures of fruit pomace and grain composite substrates. This optimizes the spatial configuration of pectin, cellulose, and starch, thereby enhancing enzymatic hydrolysis efficiency and releasing more fermentable sugars and aromatic precursors. Fermentation with *Saccharomyces cerevisiae* further increases the alcohol production rate and yield, while also improving the complexity and flavor profile of the wine, resulting in a high-quality fruit pomace composite single-strain fermented wine.

[0068] (1) Fruit pomace treatment: Select apple pomace, remove large pieces of peel and impurities, crush (particle size ≤ 5 mm), and dehydrate appropriately to a moisture content of 58%. Before enzymatic hydrolysis, prepare food-grade... Mother liquor (0.1 mol / L) is added to the pomace slurry to make the final product... The concentration is 3 mmol / L ( 0.120 g / L; for example, 30 mL of 0.1 M solution needs to be added to 1 L of slurry. The mother liquor was stirred for 10 min to ensure ion dispersion. Then pectinase (200 U / g, based on dry weight of pomace) and cellulase (100 U / g, based on dry weight of pomace) were added, the pH was adjusted to 5.0, and the enzyme was slowly stirred at 48 °C for 90 min for enzymatic hydrolysis.

[0069] (2) Grain processing: Sorghum was selected, washed to remove impurities, and then soaked to a moisture content of 32%. After soaking, the grain was first steamed (40 min) and then soaked in 85 ℃ hot water (30 min) to achieve a flowering rate of 75%. It was then steamed again (40 min) to completely gelatinize the starch and achieve a flowering rate of over 95%. Under stirring conditions, food-grade citric acid was added dropwise to the gelatinized grain slurry to adjust the pH to 5.0. Glucoamylase (150 U / g, based on the dry weight of the grain) was added at 45 ℃ and stirred for 1 h to achieve starch hydrolysis and saccharification. After steaming the rice husks for 40 min, 8 w / w% of the steamed rice husks were added based on the total raw material mass to improve aeration and release flavor substances. In addition, the fruit pomace was treated with ultrasonic or microwave assistance to break down the cell walls of the fruit pomace, promote the release of aromatic substances and polyphenols, and provide rich substrates and aroma precursors for subsequent fermentation.

[0070] (3) Inoculation of strains: The fruit pomace treated by S1 and the grain treated by S2 are mixed at a mass ratio of 50:50 to form a compound mixture. The mixture is cooled to 28 ℃ and the activated brewing yeast (Saccharomyces cerevisiae) is evenly sprinkled in at an inoculation amount of 0.1% w / w (based on the wet basis mass of the fruit pomace). After even mixing, the mixture is put into the fermentation stage.

[0071] (4) Fermentation: After the raw materials and yeast are evenly mixed, fermentation is carried out. Brewing yeast is added and pile fermentation (aerobic stage) is carried out at a temperature of 32 ℃. The aerobic fermentation time is 24 h. After the aerobic fermentation is completed, the temperature is controlled at 30 ℃ and the anaerobic fermentation is carried out for 30 days.

[0072] (5) Distillation: After primary fermentation, the wine is distilled in stages to remove the heads and tails, retaining the middle fraction. The condensation temperature is controlled at 4 ℃. The resulting wine is aged in oak barrels at a temperature of 20 ℃ and a humidity of 75% for 18 months to achieve esterification and stabilization of aromatic substances. Through scientific blending of pomace and grains, ion chelation and enzymatic pretreatment, multi-strain synergistic fermentation, and staged distillation and aging, the utilization rate of recalcitrant components in the pomace and the complexity of the wine's flavor are improved.

[0073] Example 4: A method for preparing a mixed-culture fermented fruit pomace compound wine - ion chelation enzymatic hydrolysis mixed-culture fermentation

[0074] Example 4 in the introduction , Building upon metal ion chelation enzymatic hydrolysis technology, this invention further employs a mixed-strain fermentation method using a combination of strains including *Saccharomyces cerevisiae*, *Lactobacillus plantarum*, *Rhizopus*, and aromatic yeasts. Metal ions complex with pectin and polysaccharides in the pomace and grain substrates, optimizing enzymatic hydrolysis efficiency and releasing abundant fermentable sugars and aromatic precursors. Simultaneously, it regulates the metabolic activity of each strain during the staged fermentation process, achieving yeast-dominated ethanol production, lactic acid bacteria maintaining acidity balance, and *Aspergillus* promoting starch hydrolysis and saccharification. This complex system not only increases the yield and alcohol content but also significantly enhances the complexity and flavor profile of the wine, resulting in a consistent style and high-quality pomace-fermented mixed-strain wine.

[0075] (1) Fruit pomace treatment: Select apple pomace, remove large pieces of peel and impurities, crush (particle size ≤ 5 mm), and dehydrate appropriately to a moisture content of 58%. Before enzymatic hydrolysis, prepare food-grade... Mother liquor (0.1 mol / L, (Content 0.12 g / L), add mother liquor to the pomace pulp to make the final The concentration is 3 mmol / L ( 0.120 g / L, taking 1 L of slurry as an example, requires the addition of 30 mL of 0.1 M [amount missing]. The mother liquor was stirred for 10 min to ensure ion dispersion. Then pectinase (200 U / g, based on dry weight of pomace) and cellulase (100 U / g, based on dry weight of pomace) were added, the pH was adjusted to 5.0, and the enzyme was slowly stirred at 48 °C for 90 min for enzymatic hydrolysis.

[0076] (2) Grain processing: Sorghum was selected, washed to remove impurities, and then moistened to a moisture content of 32%. After moistening, the grain was initially steamed (40 min) and then soaked in 85 ℃ hot water (30 min) to achieve a flowering rate of 75%. It was then re-steamed (40 min) to completely gelatinize the starch and achieve a flowering rate of over 95%. Under stirring conditions, food-grade citric acid was added dropwise to the gelatinized grain slurry to adjust the pH to 5.0. Glucoamylase (150 U / g, based on the dry weight of the grain) was added at 45 ℃ and stirred for 1 h to achieve starch hydrolysis and saccharification. After steaming the rice husks for 40 min, 8 w / w% of the steamed rice husks were added based on the total raw material mass to improve aeration and release flavor substances. In addition, ultrasonic or microwave-assisted treatment of the fruit pomace was combined to break down the cell walls of the fruit pomace, promote the release of aromatic substances and polyphenols, and provide rich substrates and aroma precursors for subsequent fermentation.

[0077] (3) Inoculation with compound microorganisms: The fruit pomace treated by S1 and the grain treated by S2 are mixed at a mass ratio of 50:50 to form a compound mixture. The mixture is cooled to 28 ℃ and then evenly sprinkled with compound new type of yeast. The inoculation amounts are: 0.05% w / w Rhizopus, 0.1% w / w Saccharomyces cerevisiae, 0.05% w / w Lactic acid bacteria, and 0.02% w / w Aromatic yeast (Metschnikowia pulcherrima). Fermentation is started.

[0078] (4) Fermentation: Mix the fruit pomace with the cooked grains in a certain proportion, add the compound new type of yeast, and carry out pile fermentation (aerobic stage) at 32 ℃ for 24 h to prepare food grade Mother liquor (0.05 mol / L, The mother liquor (containing 3.27 g / L) is sprayed onto the fermentation material during the initial stage of aerobic fermentation to ensure that the fermentation system contains... The final concentration was 0.10 g / L; after aerobic fermentation, the temperature was controlled at 30 ℃ for anaerobic fermentation for 30 days.

[0079] (5) Distillation: After primary fermentation, the wine is distilled in stages to remove the heads and tails, retaining the middle fraction. The condensation temperature is controlled at 4 ℃. The resulting wine is aged in oak barrels at a temperature of 20 ℃ and a humidity of 75% for 18 months to achieve esterification and stabilization of aromatic substances. Through scientific blending of pomace and grains, ion chelation and enzymatic pretreatment, multi-strain synergistic fermentation, and staged distillation and aging, the utilization rate of recalcitrant components in the pomace and the complexity of the wine's flavor are improved.

[0080] Example 5: A method for preparing a mixed-culture fermented fruit pomace compound wine, the difference from Example 3 is that in step S1, the following is added: 0.5 g / L.

[0081] Example 6: A method for preparing a mixed-culture fermented fruit pomace compound wine, the difference from Example 3 is that in step S2, 15 w / w% of steamed rice husks are added based on the total raw material mass.

[0082] Example 7: A method for preparing a mixed-culture fermented fruit pomace compound wine, the difference from Example 3 is that in step S1, the following is added: 0.5 g / L; In step S2, add 15 w / w% of steamed rice husks based on the total raw material mass.

[0083] Performance metrics:

[0084] 1) Physicochemical properties:

[0085] Moisture content of fermented mash: Moisture content was determined by gravimetric method, referring to the national standard GB 5009.3-2016 "National Food Safety Standard - Determination of Moisture in Food".

[0086] Acidity: The acidity of the fermented mash was determined by titration according to the method specified in GB 5009.239-2016 "National Food Safety Standard - Determination of Acidity in Food".

[0087] Reducing sugars: The content of reducing sugars was determined according to the method of Deepa Khatri et al. (Khatri & Chhetri, 2020).

[0088] Total nitrogen was determined in accordance with GB / T 5009.5-2025 "Determination of Protein in Food".

[0089] Ethyl acetate: Volatile compounds were analyzed by gas chromatography (GC). The analytical instrument was a Trace 1300 gas chromatograph (Thermo Fisher Scientific, USA), equipped with a flame ionization detector (FID) and a TR-WAX capillary column (30 m × 0.32 mm × 0.25 μm). For sample preparation, 0.8 mL of sample was accurately transferred to a headspace vial, diluted to 1.0 mL, sealed, and analyzed via headspace injection. Headspace injection conditions were: equilibrium temperature 80 °C, equilibrium time 30 min. Chromatographic analysis conditions were: injector temperature 220 °C; column temperature program: initial temperature 40 °C, hold for 8 min, ramp to 240 °C at a rate of 10 °C / min, hold for 2 min; detector temperature 280 °C. Carrier gas and detector gas conditions were: air flow rate 350 mL / min, hydrogen flow rate 35 mL / min.

[0090] Alcohol yield:

[0091]

[0092] In the formula: m is the yield of 55% vol raw wine, in g; M is the amount of raw materials used, in g.

[0093] The physicochemical properties of the mash obtained in the examples are shown in Table 1, and the ethyl acetate content and yield of the distilled spirits in the examples are also shown in Table 1. The radar chart of the electronic nose measurement results of the distilled spirits is shown in the figure. Figure 1 .

[0094] Table 1. List of physicochemical properties of the obtained mash, ethyl acetate content of the compound liquor, and liquor yield.

[0095] Group Moisture content of fermented mash (%) Acidity mmol / 10 g Reducing sugar % Total nitrogen g / 100 g Ethyl acetate mg / kg Alcohol yield % Example 1 74.37±0.52 2.41±0.12 1.22±0.02 0.51±0.03 645.13±22.41 52.90±0.66 Example 2 75.52±0.08 3.13±0.23 1.04±0.11 0.55±0.01 862.77±14.01 54.40±1.41 Example 3 74.88±0.36 2.67±0.19 0.89±0.19 0.62±0.04 955.04±23.37 53.70±0.96 Example 4 74.26±0.27 3.42±0.30 0.67±0.05 0.65±0.02 1273.16±2.20 60.10±0.82 Example 5 74.95±0.30 2.23±0.15 1.83±0.10 0.46±0.03 348.12±3.87 43.50±1.85 Example 6 73.93±0.35 3.85±0.08 0.54±0.12 0.52±0.02 1550.25±10.46 44.50±0.57 Example 7 74.80±0.04 3.77±0.12 1.96±0.04 0.43±0.03 344.04±11.20 40.17±0.42

[0096] Based on experience, the optimal index ranges for mash and distilled spirits are as follows (1-4 are the indexes for mash with the optimal fermentation days in S4; 5-6 are the indexes for distilled spirits in S5):

[0097] 1. Moisture content of fermented mash (%): 74.0–77.0

[0098] 2. Acidity of fermented mash (mmol / 10 g): 2.3–3.6

[0099] 3. Reducing sugars in fermented mash (%): 0.5–1.5

[0100] 4. Total nitrogen in fermented mash (g / 100 g): 0.48–0.70;

[0101] 5. Ethyl acetate for distilled spirits (mg / L): 300–1500; preferred range is 900–1300;

[0102] 6. Distilled spirits yield (%): 45–62.

[0103] Table 2. List of substances detected for each indicator of the electronic pen

[0104] Electronic nose sensor name Main response substance Electronic nose sensor name Main response substance S1 Propane, fumes, etc. S10 Hydrogen and hydrogen-containing gases S2 Carbon-containing substances S11 Hydrocarbons, carbon monoxide, etc. S3 hydrogen S12 Liquefied petroleum gas, methane S4 sulfides S13 Short-chain hydrocarbons S5 Nitrogen-containing substances S14 methane, fuel gas, smoke, etc. S6 Aldehydes and ketones S15 Carbon-containing substances, alcohols, aldehydes, etc. S7 Short-chain hydrocarbons, flammable gases, etc. S16 hydrogen sulfide S8 Liquefied gas S17 ammonia, amines, etc. S9 Hydrocarbons, alcohols, ketones, etc. S18 Toluene, acetone, ethanol, etc.

[0105] 2) Distilled spirit yield: The distilled spirit yield using the method described in the example is as follows... Figure 2 As shown.

[0106] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for preparing a mixed-culture fermented fruit pomace compound wine, characterized in that, The preparation steps include the following: S1: Fruit pomace treatment: Take the fruit pomace, dehydrate it to a moisture content of 55%-60%, and obtain fruit pomace slurry; add a solution with a concentration of 0.05-0.3 g / L to the fruit pomace slurry. and / or Metal ion solution; then add cell wall degrading enzyme, adjust pH to 4.8-5.2, and slowly stir at 35-45 ℃ to carry out enzymatic hydrolysis; S2 Grain Processing: The grains are moistened to a moisture content of 30%-35%; after moistening, the grains are steamed and soaked in hot water to fully gelatinize the starch and achieve a flowering rate of 90%-98%; 5-12 w / w% of steamed rice husks are added based on the total raw material mass. S3 Inoculation with Compound Microbial Strains: Fruit pomace and grains are mixed to form a compound mixture, and a compound novel yeast is added. The compound novel yeast is a compound microbial strain that includes at least brewing yeast and further includes at least one of Rhizopus, lactic acid bacteria and / or aromatic yeast. S4 fermentation process: Fermentation includes an aerobic stage and an anaerobic stage in sequence; Aerobic stage: After mixing the raw materials, pile them up for fermentation at a temperature of 24-38 ℃ for 12-48 h. Anaerobic stage: After the material is cooled to 25-28 ℃, it is placed in a sealed tank and anaerobic fermentation is carried out for 20-50 days; S5 Distillation and Aging: After fermentation, distillation and aging are carried out in sequence; the aging temperature is controlled at 15-20℃, the humidity is 70-80%, and the aging period is 6-24 months.

2. The method for preparing a mixed-culture fermented fruit pomace compound wine according to claim 1, characterized in that, In step S1, Addition amount: 0.1-0.3 g / L and Add 0.05-0.2 g / L.

3. The method for preparing a mixed-culture fermented fruit pomace compound wine according to claim 1 or 2, characterized in that, In step S1, the enzymatic hydrolysis time is 90-240 min.

4. The method for preparing a mixed-culture fermented fruit pomace compound wine according to claim 3, characterized in that, In step S1, the cell wall degrading enzyme includes pectinase and / or cellulase; the amount of the cell wall degrading enzyme used, based on the dry weight of the pomace, is 100-300 U / g.

5. A method for preparing a mixed-culture fermented fruit pomace compound wine according to any one of claims 1-2 and 4, characterized in that, In step S2, add 7-10 w / w% of steamed rice husks based on the total raw material mass.

6. The method for preparing a mixed-culture fermented fruit pomace compound wine according to claim 5, characterized in that, In step S2, after the grains are gelatinized and before adding the bran, the pH is adjusted to 4-5, and 150-200 U / g of glucoamylase based on the dry weight of the grains is added at 30-50 ℃. The mixture is stirred and hydrolyzed for 0.5-3 h.

7. A method for preparing a mixed-culture fermented fruit pomace compound wine according to any one of claims 1-2, 4, and 6, characterized in that, In step S3, the compound mixture contains fruit pomace and grains in a mass ratio of 30-70:70-30. The grains include any one or a combination of sorghum, glutinous rice, corn, barley, and wheat; the pomace includes any one or a combination of apple pomace, grape pomace, and pear pomace.

8. The method for preparing a mixed-culture fermented fruit pomace compound wine according to claim 7, characterized in that, In step S3, the temperature of the compound mixture is 20-35 ℃.

9. A method for preparing a mixed-culture fermented fruit pomace compound wine according to any one of claims 1-2, 4, 6, and 8, characterized in that, In step S3, the amount of the compound novel yeast is 0.1-0.4% w / w based on the weight of the compound mixture; the compound novel yeast includes at least brewing yeast, and further includes at least one of Rhizopus, lactic acid bacteria and / or aromatic yeast.

10. A compound wine made from fermented mash or mixed-culture fermented fruit pomace, obtained by the preparation method described in claims 1-9.

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