A slurry water suitable for high-flavor low-alcohol white spirit and a preparation method and application thereof

Abstract

The application discloses a kind of suitable for high flavor low alcohol liquor and its preparation method and application of slurry water, belong to food processing technical field.The method is: domestic drinking water is treated by nanofiltration membrane and reverse osmosis membrane respectively, and nanofiltration treatment water and reverse osmosis treatment water are obtained;Mix them, and control the conductivity of mixed water to be 20.0~50.5 μS / cm, pH value is 6.82~7.12, namely obtained.Use the slurry water for liquor degree reduction processing, can effectively reduce the turbidity temperature of low alcohol liquor, inhibit ester substance hydrolysis, improve sensory quality, while taking into account clarity, flavor retention and taste compatibility.The method is simple in operation, and parameter is easy to monitor on line, suitable for industrial production, with wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a diluent suitable for high-flavor, low-alcohol baijiu (Chinese liquor), its preparation method, and its application. Background Technology

[0002] Low-alcohol baijiu (Chinese white liquor) is experiencing increasing market demand due to its smooth taste and low irritation. Diluting the liquor is a core process in its production, and the diluent used for this process, as a key raw material, has crucial indicators (such as pH, conductivity, and ion concentration) that directly impact the quality of the liquor. High-quality diluent not only effectively reduces the risk of the liquor becoming cloudy or losing its luster, but also creates a synergistic effect with the flavor compounds in the base liquor, enhancing stability and flavor harmony, thereby improving the sensory quality of the product. Conversely, poor-quality diluent not only increases the risk of excessive solids and cloudiness after dilution, but also disrupts the original flavor balance, leading to a decline in the overall quality of the product after dilution.

[0003] Currently, industry research on dilution reduction processes mainly focuses on optimizing dilution methods, while the intrinsic relationship between key indicators of the added water and the quality of the liquor remains unclear. Most wineries use reverse osmosis or nanofiltration membranes to treat the added water. The main difference between the two is that added water treated by reverse osmosis membranes contains extremely low ion levels, while added water treated by nanofiltration membranes can significantly reduce calcium levels. 2+ Mg 2+ Besides turbid high-valence ions, it effectively retains other anions and cations. Gao Ling et al., in "A Preliminary Study on the Influence of Water Used for Adding Distillation on the Quality and Taste of Liquor," pointed out that different types of water used for adding distillation have a significant impact on the quality and taste of the liquor. Liu Bin et al., in "Research Progress on the Influence of Water Used for Adding Distillation on the Quality of Baijiu and Treatment Methods," systematically summarized the influence of solids, pH, and metal cations in the water used for adding distillation on the quality of the liquor. Zhang Qian et al., in "Requirements for Water Used for Adding Distillation at Different Alcohol Contents," pointed out that for water used for adding distillation in low-alcohol baijiu, a combination of microporous membrane, reverse osmosis, and resin treatment can be used to treat the water to achieve a colorless, clear, transparent, and clean finish.

[0004] The aforementioned studies provide useful references for the selection and purification of distillation water, but most remain at the level of comparing baijiu produced using different treatment methods and water samples, without revealing the quantitative relationship between distillation water and the quality of the baijiu. In actual production, the ion level of distillation water is affected by various factors such as the quality of the source water and the membrane treatment process, making it difficult to control directly and precisely, and lacking a convenient control standard. Therefore, finding a distillation water preparation method that can achieve the optimal overall quality of low-alcohol baijiu based on existing knowledge is a direction worthy of further exploration by those skilled in the art. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the prior art only reveals the general correlation between certain properties of the slurry and the quality of low-alcohol liquor, but does not give the specific physicochemical indicators or preparation process conditions of the slurry used to prepare high-quality low-alcohol liquor. Therefore, those skilled in the art cannot determine how to prepare the slurry based on this.

[0006] The purpose of this invention is to provide a method for preparing distilled water suitable for high-flavor, low-alcohol baijiu. The distilled water prepared by this method can maintain good clarity of low-alcohol baijiu after dilution, inhibit ester hydrolysis to maintain flavor stability, and has excellent sensory quality.

[0007] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows.

[0008] In a first aspect, the present invention provides a method for preparing high-flavor, low-alcohol baijiu by adding water, comprising the following steps: S1. Drinking water is treated by nanofiltration membrane and reverse osmosis membrane respectively to obtain nanofiltration treated water and reverse osmosis treated water; S2. Mix the nanofiltration treated water and the reverse osmosis treated water, and adjust the mixing ratio so that the conductivity of the mixed water is 20.0~50.5μS / cm and the pH value is 6.82~7.12, to obtain the diluent for reducing the alcohol content of high-flavor, low-alcohol baijiu.

[0009] In step S1 above, the drinking water meets the requirements of GB 5749-2022 "Standards for Drinking Water Quality".

[0010] Furthermore, the aforementioned drinking water was obtained by treating Minjiang River water, with a conductivity of 330~360μS / cm and a pH of 7.2~8.0.

[0011] In step S1 above, the conductivity of the nanofiltration treated water is 65~75 μS / cm, and the pH is 7.0~7.8.

[0012] In step S1 above, the conductivity of the reverse osmosis treated water is 4~8 μS / cm, and the pH is 5.8~6.6.

[0013] Secondly, the present invention provides a diluent prepared by the above-described method for reducing the alcohol content of high-flavor, low-alcohol baijiu.

[0014] Thirdly, the present invention provides the application of the above-mentioned water-added ingredients in the preparation of high-flavor, low-alcohol baijiu.

[0015] The above application specifically includes the following steps: a. Mix the added water with the base liquor of baijiu and reduce the alcohol content to obtain low-alcohol baijiu; b. After filtering the low-alcohol baijiu using activated carbon adsorption, a high-flavor, low-alcohol baijiu is obtained.

[0016] Furthermore, in step a above, the alcohol content of the low-alcohol liquor is 29% vol.

[0017] Furthermore, in step b above, the amount of activated carbon added is 0.03~0.05% (w / v), and the adsorption time is 8~24h.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for preparing diluent suitable for high-flavor, low-alcohol baijiu (Chinese liquor) by mixing nanofiltration-treated water and reverse osmosis-treated water, and precisely controlling the conductivity and pH value of the mixed water within specific ranges. When baijiu is diluted using this method, the resulting low-alcohol baijiu is clear, transparent, free of turbidity and sediment, with a harmonious aroma and mellow taste. Specifically, this diluent effectively lowers the turbidity temperature of low-alcohol baijiu, preventing loss of luster or sedimentation under low-temperature conditions; it also significantly inhibits the hydrolysis of ester flavor compounds during storage, maintaining the flavor stability of the liquor; and it makes the liquor more mellow and harmonious in taste, resulting in a comprehensive improvement in sensory quality. This invention effectively balances the clarity, flavor retention, and sensory quality of low-alcohol baijiu after dilution, significantly improving the overall quality of low-alcohol baijiu. Detailed Implementation

[0019] To make the technical problems, solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with the embodiments. Unless otherwise defined, all technical terms used herein have the same meaning as understood by one of ordinary skill in the art.

[0020] This invention provides a method for preparing diluent suitable for high-flavor, low-alcohol baijiu (Chinese liquor). Specifically, drinking water is treated with nanofiltration membrane and reverse osmosis membrane respectively to obtain nanofiltration-treated water and reverse osmosis-treated water; the nanofiltration-treated water and reverse osmosis-treated water are mixed, and the mixing ratio is adjusted so that the conductivity of the mixed diluent is 20.0~50.5μS / cm and the pH value is 6.82~7.12, thus obtaining diluent for reducing the alcohol content of high-flavor, low-alcohol baijiu.

[0021] In one specific embodiment of the present invention, the drinking water conforms to GB 5749-2022 "Standards for Drinking Water Quality". Taking the Minjiang River source water as an example, after treatment in the water treatment workshop, the ion content, conductivity, and pH value of this source water show relatively small fluctuations after long-term tracking analysis, indicating relatively stable water quality. Its conductivity is 330~360μS / cm, and its pH is 7.2~8.0. The water treated in the water treatment workshop is then further treated by nanofiltration membranes and reverse osmosis membranes, further reducing the fluctuation range of its effluent parameters. This makes the water quality of the nanofiltration-treated water and the reverse osmosis-treated water more stable, thus allowing for the stable production of slurry water with a conductivity of 20.0~50.5μS / cm and a pH of 6.82~7.12 through a predetermined mixing ratio.

[0022] It should be noted that the above parameter ranges are preferred intervals derived from research results on drinking water obtained after treatment in a water treatment plant from the Minjiang River. For other drinking water with stable quality after treatment in a water treatment plant, those skilled in the art can refer to the technical concept of this invention and determine the corresponding mixing ratios and parameter ranges through conventional experiments. This is a conventional adjustment that those skilled in the art can make after understanding the technical solution of this invention.

[0023] In one specific embodiment of the present invention, the above-mentioned drinking water is treated with a nanofiltration membrane to obtain nanofiltration-treated water. The nanofiltration membrane can retain most high-valence ions (such as Ca2+) in the water. 2+ Mg 2+ (Iso-turbid ions), while allowing some low-valence ions (such as K) + Na + Nanofiltration allows the permeation of small molecules and other substances. Therefore, nanofiltration-treated water typically retains a certain amount of beneficial ions, has a moderately high conductivity, and is generally weakly alkaline. In a preferred embodiment of the present invention, the conductivity of the nanofiltration-treated water is controlled at 65~75 μS / cm, and the pH value is controlled at 7.0~7.8.

[0024] In one specific embodiment of the present invention, the aforementioned drinking water is treated with a reverse osmosis membrane to obtain reverse osmosis treated water. The reverse osmosis membrane has an extremely high ion rejection rate, capable of removing most dissolved salts from the water. Therefore, the ion level of the reverse osmosis treated water is extremely low, its conductivity is typically very low, and its pH value is weakly acidic due to the presence of dissolved carbon dioxide. In a preferred embodiment of the present invention, the conductivity of the reverse osmosis treated water is controlled at 4~8 μS / cm, and the pH value is controlled at 5.8~6.6.

[0025] It should be noted that the above-mentioned index ranges for nanofiltration treated water and reverse osmosis treated water are typical values ​​obtained based on specific raw water and specific nanofiltration membrane models and reverse osmosis membrane models. In actual production, there may be slight fluctuations due to differences in membrane models and raw water quality. However, as long as there is a significant difference in ion levels between nanofiltration treated water and reverse osmosis treated water, they can be adjusted to the target range through subsequent mixing.

[0026] In one specific embodiment of the present invention, when mixing the nanofiltration treated water and the reverse osmosis treated water, since the water quality of the two types of treated water is relatively fixed (under the premise that the raw water is stable), a rough mixing ratio range can be predetermined through calculation. In actual production, operators can first mix according to the calculated ratio, and then make fine adjustments based on the conductivity and pH value monitored online. For example, when the measured conductivity is low, the proportion of nanofiltration treated water is appropriately increased; when the conductivity is high, the proportion of reverse osmosis treated water is appropriately increased. The pH value adjustment is usually related to the trend of conductivity change and does not need to be adjusted separately. During the adjustment process, conductivity and pH value should be continuously monitored to avoid adjusting too quickly and causing the indicators to exceed the range.

[0027] While existing technologies have compared the effects of diluents from different sources or processed using different methods on the quality of low-alcohol baijiu, and drawn qualitative conclusions such as weak alkalinity, moderate ion content, and the ability of metal cations to promote maturation and improve stability and taste, these conclusions are all directional suggestions. They do not provide specific physicochemical index ranges for the diluents, nor do they specify the corresponding preparation process conditions. Therefore, those skilled in the art cannot directly determine which diluent can stably produce high-quality low-alcohol baijiu based on these scattered and non-quantitative teachings.

[0028] This invention, through extensive research, has discovered a close correlation between the conductivity and pH value of the added water and the turbidity temperature, ester hydrolysis rate, and sensory quality of the diluted low-alcohol baijiu. Specifically, the optimal conductivity range is 20.0~50.5 μS / cm. Within this range, the ion concentration in the added water is suitable, effectively improving the stability of the baijiu colloids and resulting in better sensory performance after storage. The optimal pH range is 6.82~7.12. Within this range, a high level of ethyl hexanoate is maintained, which is beneficial for the retention of flavor compounds in the baijiu, while avoiding the risk of bleaching due to excessively high turbidity temperatures.

[0029] Furthermore, the present invention observed in experiments that the effects of conductivity and pH on the quality of liquor are not independent, but rather interrelated and synergistic. Only when both fall within the aforementioned ranges can the diluted liquor maintain good clarity, effectively inhibit ester hydrolysis, and possess excellent sensory quality. If the conductivity exceeds 50.5 μS / cm and the pH is close to 7.2, the sensory quality declines significantly; if the conductivity is below 20.0 μS / cm, even with a suitable pH, the ester hydrolysis rate will still increase significantly, resulting in poor sensory quality; if the pH deviates from 6.82~7.12, the flavor harmony will be significantly affected regardless of whether the conductivity is within the preferred range. Therefore, conductivity and pH must simultaneously meet the above-mentioned limiting conditions to achieve the optimal balance between clarity, ester stability, and sensory quality.

[0030] Various methods for treating slurry-treated water have been disclosed in the prior art, including nanofiltration membrane treatment, reverse osmosis membrane treatment, and combinations of both. However, these combined methods typically involve sequentially passing the raw water through nanofiltration and reverse osmosis membranes in series to further reduce the ion level and obtain purer slurry-treated water. This series treatment method can only change the ion level of the slurry-treated water in one direction (i.e., decrease it), and cannot simultaneously regulate the conductivity and pH value to a specific intermediate range. Those skilled in the art know that there is a positive correlation between the conductivity and pH value of slurry-treated water; relying solely on series treatment or single membrane treatment makes it difficult to precisely control the conductivity and pH value within a specific range while maintaining an appropriate ion concentration. More importantly, national standards for baijiu production explicitly prohibit the addition of exogenous food additives to the liquor, thus preventing the direct addition of minerals or acid-base regulators to the slurry-treated water to alter its conductivity and pH value. Therefore, how to achieve precise control of the conductivity and pH value of slurry-treated water without introducing exogenous additives has become a technical challenge for those skilled in the art.

[0031] Based on the aforementioned technical challenges, this invention creatively proposes a method of separately treating raw water through nanofiltration and reverse osmosis membranes to obtain two types of treated water with significantly different ion levels. Then, through physical mixing, the complementary nature of the differences in water quality between the two types is utilized to precisely control the conductivity and pH value of the mixed water to the target range. Unlike conventional treatment methods that involve series treatment and single-direction purification, this invention employs a separate treatment followed by mixing approach. This avoids the use of exogenous additives and achieves precise and synergistic control of conductivity and pH value, thus solving the technical challenge of simultaneously achieving clarity, ester stability, and sensory quality in low-alcohol baijiu.

[0032] This invention also provides an application of the aforementioned diluted water in the preparation of high-flavor, low-alcohol baijiu. Specifically, the diluted water is mixed with baijiu base liquor and stirred evenly to reduce the alcohol content of the base liquor to a target level (usually 38% vol or below, for example, 29% vol), resulting in low-alcohol baijiu. To further improve the clarity of the liquor, activated carbon adsorption filtration can be performed after the alcohol reduction treatment. That is, activated carbon is added to the reduced-alcohol baijiu, with the amount of activated carbon added being 0.03%~0.05% by mass-volume ratio, and the adsorption time being 8~24 hours. Activated carbon adsorption can remove trace amounts of off-flavor substances that may be present in the liquor. After adsorption is complete, the activated carbon is filtered out to obtain the finished high-flavor, low-alcohol baijiu.

[0033] The following specific embodiments will be provided to explain the solution of the present invention. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0034] Example 1 is applicable to the preparation of diluent for high-flavor, low-alcohol baijiu. (1) The raw water was selected from the Minjiang River and was treated in the water treatment workshop to meet the GB 5749-2022 "Standards for Drinking Water Quality". The conductivity, pH and content of some metal elements of the raw water were tested and the results are shown in Table 1.

[0035] (2) The above raw water was treated by nanofiltration membrane equipment and reverse osmosis membrane equipment respectively. The nanofiltration treated water and reverse osmosis treated water were collected respectively, and the conductivity, pH and content of some metal elements of the two were tested. The results are shown in Table 1.

[0036] Table 1

[0037] (3) Mix the nanofiltration treated water and reverse osmosis treated water at a certain volume ratio. During the mixing process, monitor the conductivity and pH value of the mixed water in real time. Adjust the addition ratio of the two types of water according to the monitoring results until the conductivity of the mixed water reaches 20.0~50.5μS / cm and the pH value reaches 6.82~7.12. Stop mixing to obtain the diluent for reducing the alcohol content of high-flavor, low-alcohol baijiu.

[0038] Example 2: Application of adding water in the preparation of high-flavor, low-alcohol baijiu (1) Take the nanofiltration water and reverse osmosis water prepared in Example 1 and mix them at different volume ratios. During the mixing process, monitor the conductivity and pH value of the mixed water in real time. Six groups of mixed slurry water were prepared and numbered 1 to 6. The conductivity, pH and content of some metal elements of slurry water 1 to 6 were measured respectively. The results are shown in Table 2.

[0039] Table 2

[0040] (2) Take the nanofiltration water, reverse osmosis water, and the above-mentioned slurry water 1-6 prepared in Example 1, and slowly add them to the base liquor of strong-aroma baijiu. Stir evenly and reduce the alcohol content to 29% vol. Then, add activated carbon (0.03%, w / v) for adsorption for 16 hours, filter, and obtain high-flavor, low-alcohol baijiu. Seal and store at room temperature. The turbidity temperature, sensory score, and ethyl hexanoate hydrolysis rate of each sample after 12 months of bottle storage were measured. The sensory score was comprehensively evaluated by 10 members of the sensory evaluation group from the aspects of color, aroma, and taste of the liquor, and the quality difference was ranked. The quality difference results were converted into scores (quality difference 1 to 5 were scored from 5 to 1 points respectively), and the total score was converted to 100 points. The test results are shown in Table 3.

[0041] Table 3

[0042] Table 3 shows that using only reverse osmosis water as the diluent results in a bland taste, poor layering, low sensory scores, and a high ester hydrolysis rate. Using only nanofiltration water leads to increased turbidity, a rough taste, and low sensory scores. Furthermore, the desired effect cannot be achieved with any mixing ratio of the two diluents. When the conductivity and pH of the mixed diluent exceed the limits defined in this invention, at least one indicator will significantly deteriorate. This indicates that only by mixing nanofiltration water and reverse osmosis water, and precisely controlling the conductivity and pH of the mixed water within the specified ranges, can the clarity, flavor retention, and sensory quality of low-alcohol baijiu be effectively balanced.

[0043] Example 3: Synergistic Effects of Diluent Conductivity and pH on Wine Quality (1) In order to further investigate the effect of different combinations of conductivity and pH on the quality of wine, nanofiltration water and reverse osmosis water prepared in Example 1 were mixed in different volume ratios to obtain a series of mixed slurry waters with different conductivity and pH values.

[0044] (2) Take the above series of mixed slurry water and reduce the alcohol content according to the method of Example 2 to obtain low alcohol content liquor samples. Determine the sensory score of each sample according to the sensory scoring method of Example 2, and determine the turbidity temperature and the hydrolysis rate of ethyl hexanoate after 12 months of bottle storage. The results are shown in Table 4.

[0045] It should be noted that, in order to avoid the adverse effects of the addition of exogenous substances on the quality of the wine, the conductivity and pH of all mixed water added in this embodiment of the invention are adjusted only by the combination of nanofiltration water and reverse osmosis water. Since conductivity and pH are positively correlated, it is not possible to independently control the two to cover all theoretical combinations. Some combinations cannot be achieved in actual mixing and are indicated by " / " in the table.

[0046] Table 4

[0047] As shown in Table 4, the effects of conductivity and pH on the quality of the liquor are not independent but rather work together and are indispensable. When the conductivity is below 20 μS / cm, regardless of the pH value, the ester hydrolysis rate is high and the sensory score is low. When the conductivity is above 50.5 μS / cm and the pH value is high, the turbidity temperature increases significantly and the sensory score decreases significantly. Only when the conductivity is between 20.0 and 50.5 μS / cm and the pH value is between 6.82 and 7.12 can the turbidity temperature, ester hydrolysis rate, and sensory score all reach the ideal state simultaneously. If only the conductivity range is met while the pH value deviates, or only the pH value range is met while the conductivity deviates, it is impossible for all three indicators to meet the standards simultaneously. The above results further confirm that conductivity and pH value need to be controlled synergistically; both must fall within the range defined by this invention to obtain high-quality low-alcohol liquor.

[0048] In summary, Examples 1-3 demonstrate that the method of the present invention, by controlling the conductivity and pH value of the added water within the ranges of 20.0-50.5 μS / cm and 6.82-7.12, effectively solves the problem that existing technologies struggle to simultaneously achieve clarity, stability of ester flavor compounds, and sensory quality in low-alcohol baijiu. This method is simple to operate, and the parameters are easy to monitor online, making it suitable for industrial production in baijiu enterprises and possessing broad application prospects.

Claims

1. A method for preparing high-flavor, low-alcohol baijiu by adding water, characterized in that, Includes the following steps: S1. Drinking water is treated by nanofiltration membrane and reverse osmosis membrane respectively to obtain nanofiltration treated water and reverse osmosis treated water; S2. Mix the nanofiltration treated water and the reverse osmosis treated water, and adjust the mixing ratio so that the conductivity of the mixed water is 20.0~50.5μS / cm and the pH value is 6.82~7.12, to obtain the diluent for reducing the alcohol content of high-flavor, low-alcohol baijiu.

2. The method for preparing slurry according to claim 1, characterized in that: In step S1, the drinking water meets the requirements of GB 5749-2022 "Standards for Drinking Water Quality".

3. The method for preparing slurry according to claim 2, characterized in that: The drinking water is obtained by treating Minjiang River water as a source, with a conductivity of 330~360μS / cm and a pH of 7.2~8.

0.

4. The method for preparing slurry according to claim 1, characterized in that: In step S1, the conductivity of the nanofiltration treated water is 65~75 μS / cm, and the pH is 7.0~7.

8.

5. The method for preparing slurry according to claim 1, characterized in that: In step S1, the conductivity of the reverse osmosis treated water is 4~8 μS / cm, and the pH is 5.8~6.

6.

6. The diluent prepared by the method according to any one of claims 1 to 5 for reducing the alcohol content of high-flavor, low-alcohol baijiu.

7. The application of the water added according to claim 6 in the preparation of high-flavor, low-alcohol baijiu.

8. The application according to claim 7, characterized in that, Includes the following steps: a. Mix the added water with the base liquor of baijiu and reduce the alcohol content to obtain low-alcohol baijiu; b. After filtering the low-alcohol baijiu using activated carbon adsorption, a high-flavor, low-alcohol baijiu is obtained.

9. The application according to claim 8, characterized in that: In step a, the alcohol content of the low-alcohol liquor is 29% vol.

10. The application according to claim 8, characterized in that: In step b, the amount of activated carbon added is 0.03~0.05% (w / v), and the adsorption time is 8~24 hours.

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