A method for removing turbidity by activated carbon suitable for high-flavor low-alcohol liquor

Abstract

The application discloses a kind of activated carbon turbidity removal methods suitable for high flavor low alcohol liquor, belong to food processing technical field.The method includes: selecting particle size 200 mesh, iodine adsorption value is greater than or equal to 900mg / g, barium migration is less than or equal to 5mg / kg, iron migration is less than or equal to 50mg / kg, aluminum migration is less than or equal to 50mg / kg, manganese migration is less than or equal to 15mg / kg, evaporation residue is less than or equal to 2w / % Wood activated carbon is added to low alcohol liquor, adsorbed at room temperature, stirred during, and then diatomite is filtered.The application method is limited by activated carbon metal migration amount and addition amount, while effectively removing turbidity, retaining core flavoring substances, liquor body loss temperature is less than or equal to 10 DEG C after processing, total ester loss rate is less than 5%, solid content is low, sensory quality is excellent, simple operation, suitable for industrialized batch application.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to an activated carbon turbidity removal method suitable for high-flavor, low-alcohol baijiu. Background Technology

[0002] With the transformation and upgrading of the liquor consumption market, the market demand for low-alcohol liquor continues to grow. However, low-alcohol liquor is prone to problems such as loss of luster and turbidity during the production process, which not only affects the appearance of the liquor but also reduces market acceptance. Therefore, turbidity removal has become an indispensable and crucial process in the production of low-alcohol liquor.

[0003] Activated carbon adsorption is a commonly used method for turbidity removal in the liquor industry. The porous structure of activated carbon can effectively adsorb turbid impurities in the liquor, while also removing some undesirable flavor compounds, thus improving the overall quality of the liquor. However, existing activated carbon turbidity removal processes are mostly aimed at ordinary liquor or removing off-flavors. For example, CN103131618A discloses a method for treating sauce-flavored liquor, using powdered activated carbon adsorption combined with constant temperature and humidity storage. The activated carbon addition is as high as 2% of the liquor weight, primarily for catalytic aging rather than precise turbidity removal. Zhao Jinsong et al. (Comparative Study on the Improvement of Off-Flavors in Liquor by Different Activated Carbons, *China Brewing*, 2025) compared the improvement effects of various activated carbons on off-flavored liquor, screening out activated carbons with superior overall performance. However, their research focused on removing bitterness, spiciness, and foul odors, without addressing the unique turbidity and loss of luster issues in low-alcohol liquor during the dilution process, nor providing activated carbon specifications and process conditions that can simultaneously ensure turbidity removal and high retention rates of core flavor compounds.

[0004] For low-alcohol baijiu, turbidity removal faces more stringent requirements: insufficient addition leads to incomplete turbidity removal and secondary sedimentation during shelf life; excessive addition causes over-adsorption of core flavor compounds such as ethyl hexanoate and ethyl lactate, damaging the aroma and taste of the baijiu. Furthermore, in existing activated carbon turbidity removal methods, the correlation between conventional specifications such as activated carbon particle size and iodine adsorption value and the turbidity removal effect and flavor retention of low-alcohol baijiu is unclear. This leads to reliance on experience in selecting carbon and determining processes, resulting in significant fluctuations in product quality. Therefore, developing an activated carbon turbidity removal method for high-flavor, low-alcohol baijiu that can effectively remove turbidity while maximizing the retention of core flavor compounds is of great significance for industrial production. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the existing activated carbon turbidity removal process cannot simultaneously achieve turbidity removal effect and flavor preservation when applied to low-alcohol baijiu.

[0006] The technical solution adopted by this invention to solve its technical problem is: Firstly, a method for removing turbidity with activated carbon suitable for high-flavor, low-alcohol baijiu is provided, comprising the following steps: S1. Add wood-based activated carbon to low-alcohol liquor at a mass-volume ratio of 0.03%~0.05%, and let it stand at room temperature for 8~24 hours for adsorption, stirring once every 5~10 hours during the adsorption period; The activated carbon has a particle size of 200 mesh, an iodine adsorption value ≥900 mg / g, a barium migration ≤5 mg / kg, an iron migration ≤50 mg / kg, an aluminum migration ≤50 mg / kg, a manganese migration ≤15 mg / kg, and an evaporation residue ≤2 w / %; S2. After adsorption is complete, filter to remove activated carbon particles, collect the filtrate, and you will get the treated high-flavor, low-alcohol baijiu.

[0007] Furthermore, in step S1 above, the barium migration of the wood-based activated carbon is ≤4 mg / kg, iron migration is ≤40 mg / kg, aluminum migration is ≤45 mg / kg, manganese migration is ≤13 mg / kg, and evaporation residue is ≤0.5 w / .

[0008] Furthermore, in step S1 above, the amount of wood-based activated carbon added is 0.03% by mass-volume ratio.

[0009] Furthermore, in step S1 above, the adsorption time is 16 hours, and the mixture is stirred once every 8 hours during the adsorption period.

[0010] Furthermore, in step S1 above, the room temperature is 20~24℃.

[0011] Furthermore, in step S1 above, the low-alcohol baijiu is a strong-aroma baijiu.

[0012] Furthermore, in step S1 above, the alcohol content of the low-alcohol liquor is ≤38% vol.

[0013] Furthermore, the alcohol content of the aforementioned low-alcohol baijiu is 29% vol.

[0014] Furthermore, in step S2 above, diatomaceous earth filtration is used to remove activated carbon particles.

[0015] Secondly, the present invention provides the use of the above-mentioned activated carbon turbidity removal method in the reduction and turbidity removal of low-alcohol-content strong-aroma baijiu.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses specialized wood-based activated carbon with a particle size of 200 mesh, an iodine adsorption value of not less than 900 mg / g, and metal migration (barium, iron, aluminum, manganese) and evaporation residue that meet strict requirements. With appropriate addition amount and adsorption time, it can effectively remove turbidity components from low-alcohol baijiu while effectively reducing the excessive adsorption of key flavor substances such as ethyl hexanoate and ethyl lactate, thus achieving a good balance between turbidity removal and flavor preservation.

[0017] The wine treated with this invention can have its gloss loss temperature reduced to below 10℃, meeting the national standard requirement of ≤10℃. It remains clear and stable during long-term storage, without turbidity or loss of gloss. The core flavor compounds are highly retained, with main esters such as ethyl hexanoate, ethyl lactate, ethyl butyrate, and ethyl acetate all retaining over 95%, while the total ester loss rate is only about 4%, thus fully preserving the original wine's characteristic style. The treated wine is clear and transparent in appearance, with a rich and harmonious aroma, a mellow and smooth taste, and excellent overall sensory quality. Furthermore, this invention features a simple process, low production cost, and requires no complex specialized equipment, making it directly applicable to industrial-scale mass production and possessing strong practicality and promotional value. Detailed Implementation

[0018] 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.

[0019] This invention provides an activated carbon turbidity removal method suitable for high-flavor, low-alcohol baijiu (Chinese liquor). The technical solution of this invention will be described in detail below with reference to specific operating steps.

[0020] Step 1: Selection of Activated Carbon Wood-based activated carbon was selected as the adsorption medium. The particle size of the wood-based activated carbon was 200 mesh, and its iodine adsorption value was ≥900 mg / g, barium migration was ≤5 mg / kg, iron migration was ≤50 mg / kg, aluminum migration was ≤50 mg / kg, manganese migration was ≤15 mg / kg, evaporation residue was ≤2 w / %, and other indicators met the requirements of national and enterprise standards.

[0021] Existing technologies, when screening activated carbon for winemaking, typically focus only on adsorption performance indicators such as iodine adsorption value, specific surface area, and pore size distribution, as well as conventional physicochemical indicators such as particle size, moisture content, and ash content. The core objective is to pursue higher adsorption capacity. This invention first limits the iodine adsorption value and particle size of the activated carbon to ensure it has sufficient specific surface area and adsorption capacity, thereby achieving effective turbidity removal with extremely low addition amounts. The lower the iodine adsorption value, the greater the amount of activated carbon required to achieve the same turbidity removal effect. If the iodine adsorption value is lower than the value limited by this invention, the addition amount must be increased to meet the turbidity removal requirements. However, excessive addition can lead to over-adsorption of core flavor substances, severely affecting the sensory quality of the base wine and increasing the difficulty of subsequent diatomaceous earth filtration and the risk of activated carbon residue.

[0022] Secondly, this invention discovered in its research that the amount of metal migration from activated carbon is also a key factor affecting the treatment effect in the turbidity removal process of low-alcohol baijiu. "Migration" refers to the phenomenon where specific metal elements (such as barium, iron, aluminum, and manganese) and non-volatile inorganic impurities contained in activated carbon dissolve or are released into the baijiu liquid from the solid phase of the activated carbon during contact with the low-alcohol baijiu. This migration process is affected by factors such as the source of the activated carbon, the activation process, and the degree of acid washing. The migration amount is expressed as the mass of metal elements migrating into the baijiu per kilogram of activated carbon (mg / kg) or the mass percentage of evaporation residue (w / %). This invention ensures that the treated baijiu will not experience increased gloss temperature, excessive solids, or flavor deterioration due to the dissolution of impurities from activated carbon by limiting the amount of metal migration from the activated carbon.

[0023] Experiments show that, under the same addition amount and adsorption conditions, the gloss loss temperature of the treated low-alcohol baijiu (Chinese liquor) increases significantly with the increase of the migration of barium, iron, aluminum, and manganese from the activated carbon. This is because the metal ions (especially multivalent ions) migrating into the liquor disrupt the stability of the colloidal system in the low-alcohol baijiu, promoting the aggregation and precipitation of large turbidity-causing substances, resulting in gloss loss and turbidity at higher temperatures. To ensure that the gloss loss temperature of the treated liquor meets the national standard (≤10℃), the aforementioned metal migration amounts must be controlled within the range defined in this invention.

[0024] Furthermore, existing technologies typically do not impose strict requirements on the evaporation residue (i.e., the content of non-carbon impurities) of activated carbon. However, this invention has found that the evaporation residue contained in activated carbon can enter the liquor during the processing, increasing the content of non-volatile substances in the liquor and leading to an increase in the solids content of the finished product, even exceeding the standard limit. Therefore, this invention also limits the evaporation residue to ≤2w / %, to ensure that the solids content meets the standard.

[0025] Step Two: Addition and Adsorption of Activated Carbon Add the selected wood-based activated carbon from step one to the low-alcohol liquor to be treated at a mass-volume ratio of 0.03% to 0.05%. Then, allow it to stand at room temperature (usually 20 to 24°C) for adsorption for 8 to 24 hours. During adsorption, stir every 5 to 10 hours to ensure that the activated carbon and the liquor are in full contact, and to avoid local adsorption saturation or sedimentation that would reduce adsorption efficiency.

[0026] In a preferred embodiment of the present invention, the amount of wood-based activated carbon added is 0.03% by mass-volume ratio. In contrast, existing technologies often require excessive addition (usually 0.3% or higher) to ensure thorough turbidity removal, but this leads to the adsorption of large amounts of core flavor compounds such as ethyl hexanoate and ethyl lactate, resulting in a weak aroma and rough taste in the wine. The key to the excellent turbidity removal effect achieved by the present invention with a much lower dosage lies in the strict screening of activated carbon in step one: a high iodine adsorption value ensures turbidity removal capability at low dosage; low metal migration avoids the increase in light loss temperature caused by the introduction of metal ions, eliminating the need to add additional carbon to compensate for insufficient colloidal stability. This extremely low addition not only achieves the ideal turbidity removal effect but also significantly reduces the non-specific adsorption of flavor compounds, keeping the total ester loss rate at an extremely low level, and achieving a core ester retention rate of over 95%.

[0027] In a preferred embodiment of the present invention, the adsorption time is 16 hours, with stirring every 8 hours during the adsorption period. If the adsorption time is too short, the turbid substances will not be fully adsorbed, resulting in a higher gloss loss temperature of the treated wine and a higher likelihood of secondary precipitation during shelf life. If the adsorption time is too long, it not only reduces production efficiency but may also cause adsorbed esters to desorb and re-enter the wine, or disrupt the original acid-ester balance of the wine due to prolonged contact, affecting the flavor harmony. Therefore, 16 hours is the preferred adsorption time to achieve sufficient turbidity removal with minimal flavor loss; stirring every 8 hours maintains the concentration gradient between the solid and liquid phases, ensuring the adsorption process continues efficiently.

[0028] Step 3: Diatomaceous earth filtration After adsorption, diatomaceous earth filtration is used to remove activated carbon particles from the liquor, and the filtrate is collected to obtain the treated high-flavor, low-alcohol liquor.

[0029] 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.

[0030] Example 1 (1) Preparation of activated carbon: Take wood-based activated carbon with a particle size of 200 mesh, an iodine adsorption value of 1038 mg / g, an iron migration of 47 mg / kg, an aluminum migration of 39 mg / kg, a manganese migration of 11 mg / kg, and an evaporation residue of 1.8 w / % for later use.

[0031] (2) Sample pretreatment: The strong-aroma baijiu base liquor was diluted to 29% vol to obtain a low-alcohol baijiu with an alcohol content of 29% vol. It was observed to be slightly turbid at room temperature.

[0032] (3) Activated carbon turbidity removal: Weigh the above-mentioned wood-based activated carbon at a mass-volume ratio of 0.03%, add it to the diluted liquor, stir thoroughly, and let it stand at room temperature for 16 hours for adsorption, stirring once every 8 hours during this period. After adsorption, use diatomaceous earth filtration to remove activated carbon particles and collect the filtrate.

[0033] The treated wine samples were analyzed for turbidity removal, flavor compound content, and sensory evaluation. Sensory scoring was conducted by a 10-member sensory evaluation panel, assessing the wine's color, aroma, and taste, and ranking the poorest performers. These poorest performers were then converted into scores (5 to 1 point for the 1st to 5th poorest performers), with a total score of 100. Results showed that the treated wine was clear and transparent, with a turbidity temperature of 7.9℃; the retention rates of ethyl hexanoate, ethyl lactate, ethyl butyrate, and ethyl acetate all exceeded 96%, with a total ester loss of approximately 3.5%; the sensory score was 96 points, indicating a rich and harmonious aroma, a mellow and smooth taste, and full preservation of the original wine's typical style.

[0034] Example 2 (1) Preparation of activated carbon: Take wood-based activated carbon with a particle size of 200 mesh, an iodine adsorption value of 1063 mg / g, an iron migration of 41 mg / kg, an aluminum migration of 41 mg / kg, a manganese migration of 12 mg / kg, and an evaporation residue of 1.5 w / % for later use.

[0035] (2) Sample pretreatment: The strong-aroma baijiu base liquor was diluted to 29% vol to obtain a low-alcohol baijiu with an alcohol content of 29% vol. It was observed to be slightly turbid at room temperature.

[0036] (3) Activated carbon turbidity removal: Weigh the above-mentioned wood-based activated carbon at a mass-volume ratio of 0.03%, add it to the diluted liquor, stir thoroughly, and let it stand at room temperature for 16 hours for adsorption, stirring once every 8 hours during this period. After adsorption, use diatomaceous earth filtration to remove activated carbon particles and collect the filtrate.

[0037] The treated wine samples were analyzed for turbidity removal, flavor compound content, and sensory evaluation. Results showed that the treated wine was clear and transparent, with a turbidity temperature of 7.7℃; the retention rates of ethyl hexanoate, ethyl lactate, ethyl butyrate, and ethyl acetate were all approximately 95%, with a total ester loss rate of about 4.4%; the sensory score was 95 points, indicating a rich and harmonious aroma, a mellow and smooth taste, and full preservation of the original wine's typical style.

[0038] Comparative Example 1 Five types of activated carbon with similar metal migration and evaporation residue values ​​(iodine adsorption values ​​of 675 mg / g, 796 mg / g, 907 mg / g, 1038 mg / g, and 1152 mg / g) were used to treat 29% vol strong-aroma baijiu. The minimum addition amount required to meet the turbidity removal requirements was 0.05%, 0.04%, 0.03%, 0.03%, and 0.03%, respectively. All other conditions were the same as in Example 1.

[0039] Sensory evaluation analysis was performed on the treated wine samples. The results showed that: when the iodine adsorption value was 675 mg / g, the sensory score was 66 points with an addition of 0.05%; when the iodine adsorption value was 796 mg / g, the sensory score was 72 points with an addition of 0.04%; when the iodine adsorption value was 907 mg / g, the sensory score was 92 points with an addition of 0.03%; when the iodine adsorption value was 1038 mg / g, the sensory score was 90 points with an addition of 0.03%; and when the iodine adsorption value was 1152 mg / g, the sensory score was 92 points with an addition of 0.03%.

[0040] The results show that when the iodine adsorption value is below 900 mg / g, the amount added needs to be increased to achieve the desired turbidity removal effect. This not only leads to a significant decrease in sensory scores (66-72 points), but also increases the difficulty of subsequent diatomaceous earth filtration, reduces filtration cleanliness, and the excessive amount itself has a significant negative impact on sensory quality. Therefore, considering cost, turbidity removal effect, and sensory quality, this invention limits the iodine adsorption value to ≥900 mg / g to ensure effective turbidity removal and flavor protection at a low addition amount of 0.03%.

[0041] Comparative Example 2 Four types of activated carbon with different metal migration amounts (barium, iron, aluminum, and manganese) (similar iodine adsorption values ​​and evaporation residues) were used to treat 29% vol strong-aroma baijiu with an addition amount of 0.03%, and other conditions were the same as in Example 1. The metal migration amounts of the four types of activated carbon and the gloss loss temperatures of the treated baijiu samples are as follows.

[0042] The migration amounts of barium, iron, aluminum, and manganese in activated carbon 1 were 2.877 mg / kg, 31.264 mg / kg, 33.201 mg / kg, and 8.483 mg / kg, respectively, and the light loss temperature was 9.3℃.

[0043] The migration amounts of barium, iron, aluminum, and manganese in activated carbon 2 were 3.708 mg / kg, 39.895 mg / kg, 44.408 mg / kg, and 12.118 mg / kg, respectively, and the light loss temperature was 9.5℃.

[0044] The migration amounts of barium, iron, aluminum, and manganese in activated carbon 3 were 5.142 mg / kg, 50.796 mg / kg, 52.356 mg / kg, and 15.369 mg / kg, respectively, and the light loss temperature was 9.8℃.

[0045] The migration amounts of barium, iron, aluminum, and manganese in activated carbon 4 were 6.351 mg / kg, 62.830 mg / kg, 63.229 mg / kg, and 18.271 mg / kg, respectively, and the light loss temperature was 10.1℃.

[0046] The results show that as the migration amounts of barium, iron, aluminum, and manganese in the activated carbon increased, the gloss loss temperature of the treated liquor samples gradually rose from 9.3℃ to 10.1℃. When the metal migration amounts exceeded the ranges defined in this invention (iron > 50 mg / kg, aluminum > 50 mg / kg, manganese > 15 mg / kg, barium > 5 mg / kg), the gloss loss temperature exceeded 10℃, failing to meet national standards. Therefore, the metal migration amounts defined in this invention are crucial for ensuring that the gloss loss temperature of low-alcohol liquor meets the standards.

[0047] Comparative Example 3 Four types of activated carbon (with similar iodine adsorption values ​​and metal migration rates) with evaporation residues of 0.41%, 1.98%, 3.70%, and 5.01% were used to treat 29% vol strong-aroma baijiu with an addition amount of 0.03%, and other conditions were the same as in Example 1. The solid content of the treated baijiu samples was analyzed, and the untreated original baijiu sample was used as a control.

[0048] The results showed that the solids content of the original wine sample was 0.05 g / L. After treatment with activated carbon containing 0.41% evaporation residue, the solids content was 0.06 g / L; when the evaporation residue was 1.98%, the solids content was 0.09 g / L; when the evaporation residue was 3.70%, the solids content increased to 0.13 g / L; and when the evaporation residue was 5.01%, the solids content further increased to 0.19 g / L.

[0049] The results show that when the activated carbon evaporation residue exceeds 2%, the solids content of the treated wine sample increases significantly (from 0.09 g / L to over 0.13 g / L), easily exceeding the standard limit. Therefore, this invention limits the activated carbon evaporation residue to ≤2 w / %, to ensure that the solids content of the finished wine does not exceed the standard.

[0050] In summary, this invention, by selecting specific wood-based activated carbon and combining it with low addition amounts and suitable adsorption times, can effectively remove turbidity-causing substances from low-alcohol baijiu while significantly reducing the adsorption of core flavor compounds, achieving a balance between turbidity removal and flavor preservation. Examples 1 and 2 verify that the turbidity temperature of the baijiu treated by this method can be reduced to below 10°C, the retention rate of core esters reaches over 95%, the total ester loss rate is less than 5%, the solids content is controllable, and the sensory score is excellent. Comparative Examples 1-3 further confirm that if the iodine adsorption value of the activated carbon is below 900 mg / g, the metal migration exceeds the limits of this invention, or the evaporation residue exceeds 2 w / %, it will lead to problems such as a decrease in sensory score, exceeding the turbidity temperature limit, or an increase in solids content, failing to simultaneously meet the requirements for turbidity removal, aroma preservation, and product stability in low-alcohol baijiu. Therefore, this invention provides a standardized, stable, and industrially applicable activated carbon turbidity removal method for high-flavor, low-alcohol baijiu, demonstrating significant technological advancement and application value.

Claims

1. A method for removing turbidity with activated carbon suitable for high-flavor, low-alcohol baijiu, characterized in that, Includes the following steps: S1. Add wood-based activated carbon to low-alcohol liquor at a mass-volume ratio of 0.03%~0.05%, and let it stand at room temperature for 8~24 hours for adsorption, stirring once every 5~10 hours during the adsorption period; The activated carbon has a particle size of 200 mesh, an iodine adsorption value ≥900 mg / g, a barium migration ≤5 mg / kg, an iron migration ≤50 mg / kg, an aluminum migration ≤50 mg / kg, a manganese migration ≤15 mg / kg, and an evaporation residue ≤2 w / %; S2. After adsorption is complete, filter to remove activated carbon particles, collect the filtrate, and you will get the treated high-flavor, low-alcohol baijiu.

2. The activated carbon turbidity removal method according to claim 1, characterized in that: In step S1, the barium migration of the wood-based activated carbon is ≤4 mg / kg, iron migration is ≤40 mg / kg, aluminum migration is ≤45 mg / kg, manganese migration is ≤13 mg / kg, and evaporation residue is ≤0.5 w / .

3. The activated carbon turbidity removal method according to claim 1, characterized in that: In step S1, the amount of wood-based activated carbon added is 0.03% by mass-volume ratio.

4. The activated carbon turbidity removal method according to claim 1, characterized in that: In step S1, the adsorption time is 16 hours, and the mixture is stirred once every 8 hours during the adsorption period.

5. The activated carbon turbidity removal method according to claim 1, characterized in that: In step S1, the room temperature is 20~24℃.

6. The activated carbon turbidity removal method according to claim 1, characterized in that: In step S1, the low-alcohol baijiu is a strong-aroma baijiu.

7. The activated carbon turbidity removal method according to claim 1, characterized in that: In step S1, the alcohol content of the low-alcohol liquor is ≤38%vol.

8. The activated carbon turbidity removal method according to claim 7, characterized in that: In step S1, the alcohol content of the low-alcohol liquor is 29% vol.

9. The activated carbon turbidity removal method according to claim 1, characterized in that: In step S2, diatomaceous earth filtration is used to remove activated carbon particles.

10. The use of the activated carbon turbidity removal method according to any one of claims 1 to 9 in the reduction and turbidity removal of low-alcohol strong-aroma baijiu.