A multi-stage distillation and fractional quality improvement process for baijiu (Chinese liquor)

Abstract

This invention relates to the field of baijiu (Chinese liquor) blending technology, specifically a multi-stage distillation and fractional quality improvement process for baijiu. The process includes: pretreatment of food-grade mash to obtain ionized mash; distillation of the ionized mash; and collection of the distillation products. The distillation process comprises a first stage, a second stage, and a third stage. In this invention, the adsorption and oxidation of the adsorption substrate effectively removes impurities such as heavy metals and sulfides. Simultaneously, the catalytic oxidation by novel nano-copper enhances the stability of the liquor. The fractional activated carbon in the second stage ensures maximum adsorption efficiency, preventing excessive adsorption that could lead to the loss of effective components. The fractional addition of the esterification catalyst in the third stage controls the reaction rate, preventing violent reactions from disrupting the liquor's balance. The esterification reaction generates esters that enhance the aroma layers, resulting in a liquor that combines purity and flavor richness, meeting the modern demand for high-quality and healthy baijiu.

Description

Technical Field

[0001] This invention relates to the field of baijiu (Chinese liquor) blending technology, specifically a multi-stage distillation and fractional quality improvement process for baijiu. Background Technology

[0002] Baijiu refers to a colorless and transparent distilled spirit with a high alcohol content, unique aroma, and lingering aftertaste, made primarily from sorghum, rice, corn, wheat, glutinous rice, and potatoes through processes such as saccharification, fermentation, distillation, and aging. Its alcohol content is typically between 40% and 65% vol. It is one of the most representative solid-state fermented distilled spirits among traditional Chinese alcoholic beverages. Due to its complex production process and high quality, it is hailed as "liquid gold." In addition to its drinking value, baijiu is also widely used in cooking, medicine, and seasoning.

[0003] Traditional distillation processes have numerous limitations in improving the quality of baijiu (Chinese liquor). They struggle to comprehensively and effectively address issues such as turbidity, off-flavors, and insufficient flavor. Because they lack targeted and segmented control in processing impurities and flavor compounds, removal is incomplete and retention is insufficient, affecting the purity and taste of the liquor. Furthermore, the adsorbents used in traditional processes are limited in function and prone to secondary contamination, failing to achieve comprehensive purification. Adding excessive amounts of adsorbents or catalysts at once not only increases costs but may also lead to the loss of effective flavor components, disrupting the original aroma balance of the liquor. Esterification catalysis reactions in traditional processes are often difficult to precisely control, such as temperature and the timing of catalyst addition, leading to uncontrollable reaction rates, increased side reactions, and reduced efficiency in ester formation and flavor harmony. These problems result in uneven quality improvement effects from traditional processes, failing to meet the growing demands of modern baijiu for high quality, complex flavors, and stability.

[0004] Therefore, the present invention provides a multi-stage distillation and fractional quality improvement process for baijiu (Chinese liquor) to solve the aforementioned related technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-stage distillation and fractional quality improvement process for baijiu (Chinese liquor). Through the adsorption and oxidation of the adsorption substrate, impurities such as heavy metals and sulfides can be effectively removed. At the same time, the catalytic oxidation of novel nano-copper can improve the stability of the liquor. The second-stage fractional activated carbon ensures maximum adsorption efficiency and avoids loss of effective components due to excessive one-time addition. The fractional addition of the third-stage esterification catalyst can control the reaction rate and avoid violent reactions that disrupt the balance of the liquor. The esterification reaction generates esters that enhance the aroma layers. The final liquor has both purity and rich flavor, meeting the modern demand for high-quality and healthy baijiu.

[0006] To achieve the above objectives, the present invention provides the following technical solution: like Figure 1As shown, a multi-stage distillation and fractional quality improvement process for baijiu (Chinese liquor) includes the following steps: Food-grade fermented mash is pretreated to obtain ionized fermented mash, which is then distilled to collect the distillation products. The distillation process includes a first stage, a second stage, and a third stage. First stage: Prepare chitosan solution, mix palladium chloride and sodium borohydride to obtain nanocolloid, mix chitosan solution and nanocolloid to form composite sol, cross-link composite solution to obtain adsorption substrate, immerse adsorption substrate in copper sulfate solution to obtain novel nanocopper, mix novel nanocopper with ionized wine mash to obtain clarified wine; The second stage: Food-grade activated carbon is added in five equal portions and stirred to obtain an activated carbon mixture. The activated carbon mixture is then filtered multiple times to obtain the filtered wine. The third stage involves adding the esterification catalyst in equal amounts three times, followed by heating in a water bath to form the esterified liquor. The catalyst is then removed from the esterified liquor to obtain the final liquor.

[0007] Furthermore, the pretreatment of food-grade fermented mash specifically includes: Add 0.1% to 0.5% (by weight) of 1-butyl-3-methylimidazole chloride to food-grade fermented mash and stir for 30 to 35 minutes to form ionized fermented mash. The temperature is raised to 72–75°C, the steam flow rate is 1.4–1.6 L / min, the condensation temperature is 9–11°C, and the initial steam flow is collected to obtain the initial fraction.

[0008] Furthermore, the preparation of the chitosan solution specifically involves: Chitosan and deionized water were mixed at a mass ratio of 1:45-55. Acetic acid was added dropwise to adjust the pH to 4.5-5.0. The mixture was heated in a water bath at 55-65°C and stirred for 1.5-2.5 hours. After stirring, the mixture was degassed in a vacuum of <10 Pa for 25-35 minutes to obtain a chitosan solution.

[0009] Furthermore, the specific steps for obtaining the nanocolloids are as follows: Palladium chloride was dissolved in deionized water at a molar ratio of 0.04–0.06 mmol / mL and stirred for 20–30 min. During stirring, sodium borohydride solution of 9%–11% by mass of deionized water was added to obtain a brown solution. The brown solution was then centrifuged to obtain nanocolloids. Chitosan solution and nanocolloids were mixed at a mass ratio of 1:0.4 to 0.6 and stirred in a constant temperature water bath at 40 to 45°C for 1.5 to 2.5 hours to obtain a composite sol.

[0010] Furthermore, the crosslinking treatment of the composite solution includes: Add 0.4% to 0.6% of the composite sol with glutaraldehyde solution, stir for 30 to 40 minutes, freeze at -75 to -85°C for 10 to 14 hours after stirring, and then dry in a vacuum at -45 to -55°C for 45 to 50°C to obtain the adsorption substrate.

[0011] Furthermore, the specific steps for obtaining the novel nano-copper are as follows: The adsorbent substrate was immersed in copper sulfate solution at a mass ratio of 1:9 to 11 and stirred at a constant temperature of 35 to 45°C for 1.8 to 2.2 hours to form a copper complex. An equal proportion of ascorbic acid solution was added to the copper complex, and sodium hydroxide solution was added dropwise to adjust the pH to 6.8 to 7.2. The reaction was carried out at 55 to 65°C for 30 to 40 minutes to obtain loaded copper nanoparticles. The loaded copper nanoparticles were washed 2-4 times with hydrochloric acid solution. After washing, the nanoparticles were centrifuged for 10-15 minutes, and the solid material was collected and dried in a vacuum at 55-60°C for 1.8-2.2 hours to obtain novel copper nanoparticles.

[0012] Furthermore, the specific steps for obtaining the filtered wine are as follows: The initial fraction was filtered, and citric acid solution was added dropwise to adjust the pH to 3.8–4.2 to obtain the pretreated wine. The novel nano-copper is mixed with anhydrous ethanol at a mass ratio of 1:18-22 and ultrasonically treated for 10-20 minutes to form a nano-copper suspension. The suspension is then mixed with pretreated wine at a mass ratio of 1:15-25, and polyvinylpyrrolidone (8%-12% by mass of the novel nano-copper) is added. The mixture is stirred at a constant temperature of 60-65℃ for 30-40 minutes to form a wine mixture. The temperature is then lowered to 28-32℃, and oxygen is introduced to continue the reaction for 70-75 hours to form a clarified wine.

[0013] Furthermore, the multiple filtrations of the activated carbon mixture are specifically as follows: The activated carbon mixture was filtered using a plate and frame filter press to obtain the initial filtered liquor. The initial filtered liquor was then mixed with diatomaceous earth at a solid-liquid ratio of 0.4–0.6 g / L and stirred for 10–15 minutes. The mixture was then filtered through a diatomaceous earth filter to obtain the filtered liquor.

[0014] Furthermore, the specific steps for forming the esterified liquor are as follows: Add 0.05% to 0.1% of the esterification catalyst to the filtered wine in five equal portions, stirring while adding, with an interval of 5 to 8 minutes between each addition. After the addition is complete, set the temperature to 65 to 75°C and allow it to react for 2 to 4 hours to obtain the esterified wine. Add 0.4% to 0.6% of the esterified liquor to an ion exchange resin, stir for 1.5 to 2.5 hours, and then filter to obtain the final liquor.

[0015] Furthermore, the esterification catalyst is selected from any one of ammonium bisulfate, dodecyl phosphotungstic acid, and silicomolybdic acid.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention achieves wine quality improvement through a three-stage synergistic process. The first stage utilizes a composite of chitosan and nano-palladium colloids to form an adsorption substrate, which is then treated with copper sulfate solution to generate novel nano-copper. This nano-copper removes impurities and promotes clarification through adsorption and redox reactions. The second stage involves adding activated carbon in stages and then stirring and filtering to deeply adsorb pigments and off-flavors. The third stage uses esterification catalysts added in stages and heated in a water bath to promote alcohol-esterification reactions and generate flavor compounds. Finally, ion exchange resin is used to remove residual catalysts. This third stage specifically addresses issues such as wine turbidity, off-flavors, and insufficient flavor, forming a gradient quality improvement system from physical adsorption to chemical catalysis.

[0017] The adsorption and oxidation of the adsorption substrate can effectively remove impurities such as heavy metals and sulfides. At the same time, the catalytic oxidation of novel nano-copper can improve the stability of the liquor. The second-stage activated carbon ensures maximum adsorption efficiency and avoids loss of effective components due to excessive one-time addition. The third-stage esterification catalyst can control the reaction rate and avoid violent reactions that would disrupt the balance of the liquor. The esterification reaction generates esters that enhance the aroma layers. In the end, the liquor has both purity and rich flavor, which meets the high-quality and health-oriented requirements of modern baijiu. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is the overall flow chart of the multi-stage distillation and fractional quality improvement process for baijiu (Chinese liquor) of the present invention; Figure 2 Line graph showing the quality test results of the multi-stage distillation and fractional quality improvement process for baijiu (Chinese liquor) according to the present invention. Figure 3 This is a comparative chart showing the environmental performance of the multi-stage distillation and fractional quality improvement process for baijiu (Chinese liquor) according to the present invention. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In this embodiment, unless otherwise specified, all raw materials are conventional commercial products. Among them, the particle size of the nanocolloid is 8-10nm, the chitosan is purchased from Shaanxi Yuanye Biotechnology Co., Ltd., the food-grade activated carbon is purchased from Zhengzhou Zhongchuang Water Purification Materials Co., Ltd., and the diatomite is purchased from Lingshou County Shuntian Mineral Products Processing Plant. The ascorbic acid solution was prepared by mixing vitamin C with deionized water at a molar ratio of 0.15 mol / L. The vitamin C was purchased from Wuhan Baixing Biotechnology Co., Ltd.

[0022] Example 1 like Figure 1 As shown, a multi-stage distillation and fractional quality improvement process for baijiu (Chinese liquor) includes the following steps: The quality improvement process includes the following steps: Food-grade fermented mash is pretreated to obtain ionized fermented mash, which is then distilled to collect the distillation products. The distillation process includes a first stage, a second stage, and a third stage. First stage: Prepare chitosan solution, mix palladium chloride and sodium borohydride to obtain nanocolloid, mix chitosan solution and nanocolloid to form composite sol, cross-link composite solution to obtain adsorption substrate, immerse adsorption substrate in copper sulfate solution to obtain novel nanocopper, mix novel nanocopper with ionized wine mash to obtain clarified wine; The second stage: Food-grade activated carbon is added in equal amounts multiple times and stirred to obtain an activated carbon mixture. The activated carbon mixture is then filtered multiple times to obtain the filtered wine. The third stage involves adding esterification catalyst in equal amounts multiple times, followed by heating in a water bath after the addition is complete to form an esterified liquor. The catalyst in the esterified liquor is then removed to obtain the final liquor.

[0023] Furthermore, the pretreatment of food-grade fermented mash specifically includes: Add 0.5% (by weight) of 1-butyl-3-methylimidazole chloride to food-grade fermented mash, stir for 35 minutes to form ionized fermented mash; The temperature was raised to 75℃, the steam flow rate was 1.6L / min, the condensation temperature was 11℃, and the initial steam flow was collected to obtain the initial fraction.

[0024] Furthermore, the preparation of the chitosan solution specifically involves: Chitosan and deionized water were mixed at a mass ratio of 1:55. Acetic acid was added dropwise to adjust the pH to 5.0. The mixture was heated in a water bath at 65°C and stirred for 2.5 hours. After stirring, the mixture was degassed in a vacuum of <10 Pa for 25-35 minutes to obtain a chitosan solution.

[0025] Furthermore, the specific steps for obtaining the nanocolloids are as follows: Palladium chloride was dissolved in deionized water at a molar ratio of 0.06 mmol / mL and stirred for 30 min. During stirring, sodium borohydride solution with a mass of 11% deionized water was added to obtain a brown solution. The brown solution was centrifuged to obtain nanocolloids. Chitosan solution and nanocolloid were mixed at a mass ratio of 1:0.6 and stirred in a constant temperature water bath at 45℃ for 2.5 h to obtain composite sol.

[0026] Furthermore, the crosslinking treatment of the composite solution includes: Add 0.6% (by mass) of glutaraldehyde solution to the composite sol, stir for 40 min, freeze at -85℃ for 14 h after stirring, and then dry in a vacuum at -55℃ for 50 h to obtain the adsorption substrate.

[0027] Furthermore, the specific steps for obtaining the novel nano-copper are as follows: The adsorbent substrate was immersed in copper sulfate solution at a mass ratio of 1:11 and stirred at 45°C for 2.2 h to form a copper complex. An equal proportion of ascorbic acid solution was added to the copper complex, and sodium hydroxide solution was added dropwise to adjust the pH to 7.2. The reaction was carried out at 65°C for 40 min to obtain loaded copper nanoparticles. The loaded copper nanoparticles were washed four times with hydrochloric acid solution. After washing, the nanoparticles were centrifuged for 15 minutes, and the solid material was collected and dried in a vacuum at 60°C for 2.2 hours to obtain novel copper nanoparticles.

[0028] Furthermore, the specific steps for obtaining the filtered wine are as follows: The initial fraction was filtered, and citric acid solution was added dropwise to adjust the pH to 4.2 to obtain the pretreated wine. The novel nano-copper was mixed with anhydrous ethanol at a mass ratio of 1:22 and ultrasonically treated for 20 minutes to form a nano-copper suspension. The suspension was mixed with the pretreated wine at a mass ratio of 1:25, and polyvinylpyrrolidone (12% by mass of the novel nano-copper) was added. The mixture was stirred at a constant temperature of 65°C for 40 minutes to form a wine mixture. The temperature was then lowered to 32°C, and oxygen was introduced to continue the reaction for 75 hours to form a clarified wine.

[0029] Furthermore, the multiple filtrations of the activated carbon mixture are specifically as follows: The activated carbon mixture was filtered using a plate and frame filter press to obtain the initial filtered wine. The initial filtered wine was then mixed with diatomaceous earth at a solid-liquid ratio of 0.6 g / L and stirred for 15 minutes. The mixture was then filtered through a diatomaceous earth filter to obtain the filtered wine.

[0030] Furthermore, the specific steps for forming the esterified liquor are as follows: Add 0.1% of the esterification catalyst to the filtered wine in five equal portions, stirring while adding, with an 8-minute interval between each addition. After the addition is complete, set the temperature to 75℃ and allow it to react for 4 hours to obtain the esterified wine. Add 0.6% by weight of ion exchange resin to the esterified liquor, stir for 2.5 hours, and then filter to obtain the final liquor.

[0031] Furthermore, the esterification catalyst is ammonium bisulfate.

[0032] Example 2 The preparation method of the multi-stage distillation and fractional upgrading process for baijiu provided in this embodiment is basically the same as that in Example 1. The main difference between the two lies in the specific composition and ratio of the raw materials used. The specific composition of the raw materials used in this embodiment is as follows: The upgrading process includes the following steps: The quality improvement process includes the following steps: Food-grade fermented mash is pretreated to obtain ionized fermented mash, which is then distilled to collect the distillation products. The distillation process includes a first stage, a second stage, and a third stage. First stage: Prepare chitosan solution, mix palladium chloride and sodium borohydride to obtain nanocolloid, mix chitosan solution and nanocolloid to form composite sol, cross-link composite solution to obtain adsorption substrate, immerse adsorption substrate in copper sulfate solution to obtain novel nanocopper, mix novel nanocopper with ionized wine mash to obtain clarified wine; The second stage: Food-grade activated carbon is added in equal amounts multiple times and stirred to obtain an activated carbon mixture. The activated carbon mixture is then filtered multiple times to obtain the filtered wine. The third stage involves adding esterification catalyst in equal amounts multiple times, followed by heating in a water bath after the addition is complete to form an esterified liquor. The catalyst in the esterified liquor is then removed to obtain the final liquor.

[0033] Furthermore, the pretreatment of food-grade fermented mash specifically includes: Add 0.5% (by weight) of 1-butyl-3-methylimidazole chloride to food-grade fermented mash, stir for 35 minutes to form ionized fermented mash; The temperature was raised to 75℃, the steam flow rate was 1.6L / min, the condensation temperature was 11℃, and the initial steam flow was collected to obtain the initial fraction.

[0034] Furthermore, the preparation of the chitosan solution specifically involves: Chitosan and deionized water were mixed at a mass ratio of 1:55. Acetic acid was added dropwise to adjust the pH to 5.0. The mixture was heated in a water bath at 65°C and stirred for 2.5 hours. After stirring, the mixture was degassed in a vacuum of <10 Pa for 35 minutes to obtain a chitosan solution.

[0035] Furthermore, the specific steps for obtaining the nanocolloids are as follows: Palladium chloride was dissolved in deionized water at a molar ratio of 0.06 mmol / mL and stirred for 30 min. During stirring, sodium borohydride solution with a mass of 11% deionized water was added to obtain a brown solution. The brown solution was centrifuged to obtain nanocolloids. Chitosan solution and nanocolloid were mixed at a mass ratio of 1:0.6 and stirred in a constant temperature water bath at 45℃ for 2.5 h to obtain composite sol.

[0036] Furthermore, the crosslinking treatment of the composite solution includes: Add 0.6% (by mass) of glutaraldehyde solution to the composite sol, stir for 40 min, freeze at -85℃ for 14 h after stirring, and then dry in a vacuum at -55℃ for 50 h to obtain the adsorption substrate.

[0037] Furthermore, the specific steps for obtaining the novel nano-copper are as follows: The adsorbent substrate was immersed in copper sulfate solution at a mass ratio of 1:11 and stirred at 45°C for 1.8–2.2 h to form a copper complex. An equal proportion of ascorbic acid solution was added to the copper complex, and sodium hydroxide solution was added dropwise to adjust the pH to 7.2. The reaction was carried out at 65°C for 40 min to obtain loaded copper nanoparticles. The loaded copper nanoparticles were washed four times with hydrochloric acid solution. After washing, the nanoparticles were centrifuged for 15 minutes, and the solid material was collected and dried in a vacuum at 60°C for 2.2 hours to obtain novel copper nanoparticles.

[0038] Furthermore, the specific steps for obtaining the filtered wine are as follows: The initial fraction was filtered, and citric acid solution was added dropwise to adjust the pH to 4.2 to obtain the pretreated wine. The novel nano-copper was mixed with anhydrous ethanol at a mass ratio of 1:22 and ultrasonically treated for 20 minutes to form a nano-copper suspension. The suspension was mixed with the pretreated wine at a mass ratio of 1:25, and polyvinylpyrrolidone (12% by mass of the novel nano-copper) was added. The mixture was stirred at a constant temperature of 65°C for 40 minutes to form a wine mixture. The temperature was then lowered to 32°C, and oxygen was introduced to continue the reaction for 75 hours to form a clarified wine.

[0039] Furthermore, the multiple filtrations of the activated carbon mixture are specifically as follows: The activated carbon mixture was filtered using a plate and frame filter press to obtain the initial filtered wine. The initial filtered wine was then mixed with diatomaceous earth at a solid-liquid ratio of 0.6 g / L and stirred for 15 minutes. The mixture was then filtered through a diatomaceous earth filter to obtain the filtered wine.

[0040] Furthermore, the specific steps for forming the esterified liquor are as follows: Add 0.1% of the esterification catalyst to the filtered wine in five equal portions, stirring while adding, with an 8-minute interval between each addition. After the addition is complete, set the temperature to 75℃ and allow it to react for 4 hours to obtain the esterified wine. Add 0.6% by weight of ion exchange resin to the esterified liquor, stir for 2.5 hours, and then filter to obtain the final liquor.

[0041] Furthermore, the esterification catalyst is selected as dodecaphosphotungstic acid.

[0042] Example 3 The preparation method of the multi-stage distillation and fractional upgrading process for baijiu provided in this embodiment is basically the same as that in Example 1. The main difference between the two lies in the specific composition and ratio of the raw materials used. The specific composition of the raw materials used in this embodiment is as follows: The upgrading process includes the following steps: The quality improvement process includes the following steps: Food-grade fermented mash is pretreated to obtain ionized fermented mash, which is then distilled to collect the distillation products. The distillation process includes a first stage, a second stage, and a third stage. First stage: Prepare chitosan solution, mix palladium chloride and sodium borohydride to obtain nanocolloid, mix chitosan solution and nanocolloid to form composite sol, cross-link composite solution to obtain adsorption substrate, immerse adsorption substrate in copper sulfate solution to obtain novel nanocopper, mix novel nanocopper with ionized wine mash to obtain clarified wine; The second stage: Food-grade activated carbon is added in equal amounts multiple times and stirred to obtain an activated carbon mixture. The activated carbon mixture is then filtered multiple times to obtain the filtered wine. The third stage involves adding esterification catalyst in equal amounts multiple times, followed by heating in a water bath after the addition is complete to form an esterified liquor. The catalyst in the esterified liquor is then removed to obtain the final liquor.

[0043] Furthermore, the pretreatment of food-grade fermented mash specifically includes: Add 0.3% (by weight) of 1-butyl-3-methylimidazole chloride to food-grade fermented mash, stir for 33 minutes to form ionized fermented mash; The temperature was raised to 73°C, the steam flow rate was 1.5 L / min, the condensation temperature was 10°C, and the initial steam flow was collected to obtain the initial fraction.

[0044] Furthermore, the preparation of the chitosan solution specifically involves: Chitosan and deionized water were mixed at a mass ratio of 1:50. Acetic acid was added dropwise to adjust the pH to 4.8. The mixture was heated in a water bath at 60°C and stirred for 2 hours. After stirring, the mixture was degassed in a vacuum of <10 Pa for 30 minutes to obtain a chitosan solution.

[0045] Furthermore, the specific steps for obtaining the nanocolloids are as follows: Palladium chloride was dissolved in deionized water at a molar ratio of 0.05 mmol / mL and stirred for 25 min. During stirring, sodium borohydride solution with a mass of 10% deionized water was added to obtain a brown solution. The brown solution was centrifuged to obtain nanocolloids. Chitosan solution and nanocolloid were mixed at a mass ratio of 1:0.5 and stirred in a constant temperature water bath at 43℃ for 1.5 to 2.5 hours to obtain composite sol.

[0046] Furthermore, the crosslinking treatment of the composite solution includes: Add 0.5% (by mass) of glutaraldehyde solution to the composite sol, stir for 35 min, freeze at -80℃ for 12 h after stirring, and then dry in a vacuum at -50℃ for 48 h to obtain the adsorption substrate.

[0047] Furthermore, the specific steps for obtaining the novel nano-copper are as follows: The adsorbent substrate was immersed in copper sulfate solution at a mass ratio of 1:9 to 11 and stirred at 40°C for 2 hours to form a copper complex. An equal proportion of ascorbic acid solution was added to the copper complex, and sodium hydroxide solution was added dropwise to adjust the pH to 7.0. The reaction was carried out at 60°C for 35 minutes to obtain loaded copper nanoparticles. The loaded copper nanoparticles were washed three times with hydrochloric acid solution. After washing, the nanoparticles were centrifuged for 13 minutes, and the solid material was collected and dried in a vacuum at 58°C for 2 hours to obtain novel copper nanoparticles.

[0048] Furthermore, the specific steps for obtaining the filtered wine are as follows: The initial fraction was filtered, and citric acid solution was added dropwise to adjust the pH to 4.0 to obtain the pretreated wine. The novel nano-copper was mixed with anhydrous ethanol at a mass ratio of 1:20 and ultrasonically treated for 15 minutes to form a nano-copper suspension. The suspension was then mixed with the pretreated wine at a mass ratio of 1:20, and polyvinylpyrrolidone (10% by mass of the novel nano-copper) was added. The mixture was stirred at a constant temperature of 63°C for 35 minutes to form a wine mixture. The mixture was then cooled to 30°C and oxygen was introduced to continue the reaction for 72 hours to form a clarified wine.

[0049] Furthermore, the multiple filtrations of the activated carbon mixture are specifically as follows: The activated carbon mixture was filtered using a plate and frame filter press to obtain the initial filtered wine. The initial filtered wine was then mixed with diatomaceous earth at a solid-liquid ratio of 0.5 g / L and stirred for 13 minutes. The mixture was then filtered through a diatomaceous earth filter to obtain the filtered wine.

[0050] Furthermore, the specific steps for forming the esterified liquor are as follows: Add 0.08% of the esterification catalyst to the filtered wine in five equal portions, stirring while adding, with a 6-minute interval between each addition. After the addition is complete, set the temperature to 70℃ and allow it to react for 3 hours to obtain the esterified wine. Add 0.5% (by weight) of ion exchange resin to the esterified liquor, stir for 2 hours, and then filter to obtain the final liquor.

[0051] Furthermore, the esterification catalyst is selected from molybdenum silicochemical acid.

[0052] Comparative Example 1: The preparation method and specific ratio of raw materials for the multi-stage distillation and fractional quality improvement process of baijiu provided in this example are roughly the same as those in Example 1. The main difference is that this example does not contain polyvinylpyrrolidone, which was purchased from Shanghai Liming Chemical Co., Ltd.

[0053] Comparative Example 2: The preparation method and specific ratio of raw materials for the multi-stage distillation and segmented quality improvement process of baijiu provided in this embodiment are roughly the same as those in Example 1. The main difference is that an equal amount of nano-copper is used instead of novel nano-copper in this embodiment.

[0054] Comparative Example 3: The preparation method and specific ratio of raw materials for the multi-stage distillation and fractional quality improvement process of baijiu provided in this embodiment are roughly the same as those in Example 1. The main difference is that in this embodiment, an equal amount of chitosan is used instead of the adsorption substrate.

[0055] Effect test The multi-stage distillation and fractional quality improvement processes of baijiu described in Examples 1-3 of this invention are designated as Experimental Examples 1-3; the multi-stage distillation and fractional quality improvement processes of baijiu described in Comparative Examples 1-3 are designated as Comparative Examples 1-3; and then the performance of each group of multi-stage distillation and fractional quality improvement processes of baijiu in equal quantities is tested.

[0056] Experimental setup: Security testing: Following the "Procedures and Methods for Food Safety Toxicology Evaluation" (GB 15193.3-2014), an acute oral toxicity experiment was conducted in mice to verify the safety of the improved wines from each example and comparative example. Sixty healthy Kunming mice (half male, half female, weighing 18-22g) were randomly divided into six groups of ten mice each, corresponding to the final wines of Examples 1-3 and Comparative Examples 1-3, respectively. A blank control group (physiological saline) was also included. The mice were administered the medication via gavage at a dose of 5000 mg / kg body weight (bw). Observations were conducted for 14 consecutive days, recording mouse survival, behavior, and changes in vital signs. After the experiment, the mice were dissected to observe for any abnormalities in their organs. All mice in the six sample groups survived without any obvious poisoning reaction or pathological damage to their organs, reaching the practically non-toxic level and meeting food safety requirements.

[0057] Catalytic effect test: Referring to the evaluation standards for esterification catalysis in the liquor industry, the esterification rate was used as the core indicator to test the catalytic efficiency of the esterification reaction during the quality improvement process of each sample. The higher the esterification rate, the better the catalytic effect. The experiment used titration to determine the content of esters in the liquor before and after the reaction, and calculated the esterification rate. Each group of samples was measured in triplicate, and the average value was taken. The experimental results are detailed in Table 1. Table 1: Catalytic Effect Table

[0058] Examples 1-3 showed good catalytic effects, with Example 1 having the highest esterification rate due to its optimal parameters. Comparative Example 1, which did not contain polyvinylpyrrolidone, Comparative Example 2, which used ordinary nano-copper, and Comparative Example 3, which used pure chitosan, all resulted in a decrease in catalytic activity or stability, demonstrating that the novel nano-copper, adsorbent substrate, and polyvinylpyrrolidone are crucial to the catalytic effect.

[0059] Wine quality testing: Test criteria: Referencing the standard "Strong-Aroma Baijiu" (GB / T 10781.1-2021), the core quality indicators of the liquor were tested, including alcohol content (%vol), total esters (g / L), total acid (g / L), and fusel oil content (mg / 100mL). Each group was measured in triplicate, and the average value was taken to evaluate the quality grade of the liquor. The data results are shown in Table 2 and... Figure 2 : Table 2: Wine Quality Test Table

[0060] Examples 1-3 all met the superior grade standard of GB / T 10781.1-2021, with sufficient total ester and total acid content, low fusel oil content, and a mellow taste and harmonious flavor. Comparative Examples 1-3 only met the first grade standard, with insufficient total ester content and high fusel oil content. This was mainly due to the substitution or absence of raw materials, leading to a decrease in purification and esterification effects. This proves that the quality improvement process of this invention can effectively improve the quality of the liquor, and the core raw materials are irreplaceable.

[0061] Process efficiency test: The total time spent on distillation and refining, and the yield of the spirit, are the core indicators for evaluating process efficiency. Shorter total time and higher yield indicate better process efficiency. Yield = final spirit mass / initial mash mass × 100%. Each experiment used the same mass (10 kg) of food-grade mash. Total time was recorded, yield was calculated, and the results were repeated twice in parallel. The average value is shown in Table 3. Table 3: Process Efficiency Table

[0062] The process efficiency of Examples 1-3 is better than that of Comparative Examples 1-3. Example 1 has the shortest total time and the highest yield. Comparative Examples 1-3 have increased reaction and purification time and decreased yield due to the replacement or absence of raw materials. This proves that the process of the present invention can effectively improve production efficiency and reduce production costs.

[0063] Environmental performance test: Referring to the "Integrated Wastewater Discharge Standard" (GB 8978-1996) and the "Pollution Control Standard for Storage and Landfill of General Industrial Solid Waste" (GB 18599-2020), the COD value of the wastewater and the amount of solid waste generated by the process were tested. The lower the COD value and the less solid waste generated, the better the environmental performance. Each experiment used 10 kg of fermented mash, collected wastewater and solid waste, and conducted two parallel measurements, taking the average value, as shown in Table 4. Figure 3 As shown: Table 4: Environmental Performance Table

[0064] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A multi-stage distillation and fractional quality improvement process for baijiu (Chinese liquor), characterized in that: The quality improvement process includes: Food-grade fermented mash is pretreated to obtain ionized fermented mash, which is then distilled to collect the distillation products. The distillation process includes a first stage, a second stage, and a third stage. First stage: Prepare chitosan solution, mix palladium chloride and sodium borohydride to obtain nanocolloid, mix chitosan solution and nanocolloid to form composite sol, cross-link composite solution to obtain adsorption substrate, immerse adsorption substrate in copper sulfate solution to obtain novel nanocopper, mix novel nanocopper with ionized wine mash to obtain clarified wine; The second stage: Food-grade activated carbon is added in equal amounts multiple times and stirred to obtain an activated carbon mixture. The activated carbon mixture is then filtered multiple times to obtain the filtered wine. The third stage involves adding esterification catalyst in equal amounts multiple times, followed by heating in a water bath after the addition is complete to form an esterified liquor. The catalyst in the esterified liquor is then removed to obtain the final liquor.

2. The multi-stage distillation and fractional quality improvement process for baijiu as described in claim 1, characterized in that: The pretreatment of food-grade fermented mash specifically involves: Add 0.1% to 0.5% (by weight) of 1-butyl-3-methylimidazole chloride to food-grade fermented mash and stir for 30 to 35 minutes to form ionized fermented mash. The temperature is raised to 72–75°C, the steam flow rate is 1.4–1.6 L / min, the condensation temperature is 9–11°C, and the initial steam flow is collected to obtain the initial fraction.

3. The multi-stage distillation and fractional quality improvement process for baijiu as described in claim 1, characterized in that: The preparation of the chitosan solution specifically involves: Chitosan and deionized water were mixed at a mass ratio of 1:45-55. Acetic acid was added dropwise to adjust the pH to 4.5-5.

0. The mixture was heated in a water bath at 55-65°C and stirred for 1.5-2.5 hours. After stirring, the mixture was degassed in a vacuum for 25-35 minutes to obtain a chitosan solution.

4. The multi-stage distillation and fractional quality improvement process for baijiu as described in claim 3, characterized in that: The specific steps for obtaining the nanocolloids are as follows: Palladium chloride was dissolved in deionized water at a molar ratio of 0.04–0.06 mmol / mL and stirred for 20–30 min. During stirring, sodium borohydride solution of 9%–11% by mass of deionized water was added to obtain a brown solution. The brown solution was then centrifuged to obtain nanocolloids. Chitosan solution and nanocolloids were mixed at a mass ratio of 1:0.4 to 0.6 and stirred in a constant temperature water bath at 40 to 45°C for 1.5 to 2.5 hours to obtain a composite sol.

5. The multi-stage distillation and fractional quality improvement process for baijiu as described in claim 4, characterized in that: The crosslinking treatment of the composite solution includes: Add 0.4% to 0.6% of the composite sol with glutaraldehyde solution, stir for 30 to 40 minutes, freeze at -75 to -85°C for 10 to 14 hours after stirring, and then dry in a vacuum at -45 to -55°C for 45 to 50°C to obtain the adsorption substrate.

6. The multi-stage distillation and fractional quality improvement process for baijiu as described in claim 5, characterized in that: The specific steps for obtaining the novel nano-copper are as follows: The adsorbent substrate was immersed in copper sulfate solution at a mass ratio of 1:9 to 11 and stirred at a constant temperature of 35 to 45°C for 1.8 to 2.2 hours to form a copper complex. An equal proportion of ascorbic acid solution was added to the copper complex, and sodium hydroxide solution was added dropwise to adjust the pH to 6.8 to 7.

2. The reaction was carried out at 55 to 65°C for 30 to 40 minutes to obtain loaded copper nanoparticles. The loaded copper nanoparticles were washed 2-4 times with hydrochloric acid solution. After washing, the nanoparticles were centrifuged for 10-15 minutes, and the solid material was collected and dried in a vacuum at 55-60°C for 1.8-2.2 hours to obtain novel copper nanoparticles.

7. The multi-stage distillation and fractional quality improvement process for baijiu (Chinese liquor) according to claim 1, characterized in that: The specific steps for obtaining the filtered wine are as follows: The initial fraction was filtered, and citric acid solution was added dropwise to adjust the pH to 3.8–4.2 to obtain the pretreated wine. The novel nano-copper is mixed with anhydrous ethanol at a mass ratio of 1:18-22 and ultrasonically treated for 10-20 minutes to form a nano-copper suspension. The suspension is then mixed with pretreated wine at a mass ratio of 1:15-25, and polyvinylpyrrolidone (8%-12% by mass of the novel nano-copper) is added. The mixture is stirred at a constant temperature of 60-65℃ for 30-40 minutes to form a wine mixture. The temperature is then lowered to 28-32℃, and oxygen is introduced to continue the reaction for 70-75 hours to form a clarified wine.

8. The multi-stage distillation and fractional quality improvement process for baijiu as described in claim 1, characterized in that: The specific steps for multiple filtrations of the activated carbon mixture are as follows: The activated carbon mixture was filtered using a plate and frame filter press to obtain the initial filtered liquor. The initial filtered liquor was then mixed with diatomaceous earth at a solid-liquid ratio of 0.4–0.6 g / L and stirred for 10–15 minutes. The mixture was then filtered through a diatomaceous earth filter to obtain the filtered liquor.

9. The multi-stage distillation and fractional quality improvement process for baijiu as described in claim 1, characterized in that: The specific steps for forming the esterified wine are as follows: Add 0.05% to 0.1% of the esterification catalyst to the filtered wine in five equal portions, stirring while adding, with an interval of 5 to 8 minutes between each addition. After the addition is complete, set the temperature to 65 to 75°C and allow it to react for 2 to 4 hours to obtain the esterified wine. Add 0.4% to 0.6% of the esterified liquor to an ion exchange resin, stir for 1.5 to 2.5 hours, and then filter to obtain the final liquor.

10. The multi-stage distillation and fractional quality improvement process for baijiu as described in claim 1, characterized in that: The esterification catalyst is selected from any one of ammonium bisulfate, dodecyl phosphotungstic acid, and molybdic acid.

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