| Nongxiangxing baijiu is a very popular alcoholic beverage in china.Its production is based on the premise of Nongxiangxing crude baijiu.However,due to various factors,Nongxiangxing crude baijiu may be brought into various flavors during the brewing process,which will affect the quality of the crude baijiu.At the same time,in order to meet the needs of finished Baijiu body design,the crude baijiu still needs to be stored and matured for a long time after being put into storage.The liquor loss during storage,the requirements for storage capacity,Baijiu storage equipment and facilities,etc will bring some burden to the enterprise.Therefore,it is necessary to study the aging process of crude baijiu and find methods that can effectively improve its quality and shorten its aging period.As a food processing auxiliary that can be used in the post-treatment stage of Baijiu production,activated carbon has the characteristics of simple process operation,low cost,low environmental burden,etc in the production and application of enterprises.It is of great significance to apply activated carbon to the impurity removal and aging of Nongxiangxing crude baijiu.Based on this,this study analyzed the changes in physicochemical indicators and sensory quality of Nongxiangxing crude baijiu in different storage time,established an evaluation basis for the effect of impurity removal and aging promotion of the crude baijiu,and then established the optimal process conditions for active carbon impurity removal and aging promotion.Finally,combined with the storage and aging process to explore the application effect of activated carbon on impurity removal and aging promotion of Nongxiangxing crude baijiu.the main research contents and results are as follows:(1)The physicochemical indexes of nine Nongxiangxing crude baijiu with different quality grades stored for 0,1,3,5,and 10 years were determined by gas chromatography and acid-base titration,respectively,and the sensory evaluation of the Baijiu samples was conducted.The results showed that the alcohol loss(AL)increased with the prolongation of storage time,and the electrical conductivity,total acid to total ester showed an overall upward trend during storage,while the p H value showed a downward trend.The sensory quality of the crude baijiu was improved.It was clarified that there were mainly changes in the ratio of chemically balanced aroma components in the Baijiu body,namely,the ratios of ethyl caproate to caproic acid,ethyl acetate to acetic acid,and n-hexanol to n-hexanal decreased during storage,while the ratios of ethyl butyrate to butyric acid,acetal to acetaldehyde,isoamyl alcohol to isoamyl acetate,caproic acid to n-hexanal,and 3-hydroxy-2-butanone to 2,3-butanediol increased.The aging time models that established for different quality grades of crude baijiu(B,C,D),using alcohol loss(X1),p H value(X2),ethyl butyrate to butyric acid(X3),caproic acid to n-hexanal(X4),3-hydroxy-2-butanone to 2,3-butanediol(X5)as the main variables related to storage time(Y)were as follows:B:Y=3.406X1+2.749X3+0.353X5,C:Y=2.652X1+1.132X3+0.004X4+0.445X5,D:Y=11.853+3.987X1-3.044X2+0.005X4+0.128X5.(2)The pore structure of four plant derived activated carbons was determined by an adsorption analyzer to determine the impact of the nature of the activated carbon on the quality of Nongxiangxing crude baijiu.Using the sensory score improvement rate(SSIR),methanol and higher alcohol removal rate(RRMA),and aroma component loss rate(FCIR)as evaluation indicators,the type of activated carbon suitable for impurity removal and aging promotion of Nongxiangxing crude baijiu was determined to be coconut shell activated carbon with a specific surface area of 266.67 m~2/g and an average adsorption pore size of 4.63 nm.The effects of activated carbon particle size,addition amount,and processing time on the quality of Nongxiangxing crude baijiu were investigated through a single factor experiment.Based on this,orthogonal experiments were designed to optimize the conditions for removing impurities and accelerating aging of Nongxiangxing crude baijiu using activated carbon,and it was found that when the particle size of activated carbon was 45-75μm Under the combined conditions of adding 2 g/L of impurities and adsorption time of 36 hours,the effect of impurity removal and aging promotion was significant,and the quality of the original liquor was improved.The factors affecting the effect of impurity removal and aging promotion of Nongxiangxing crude baijiu were the addition amount of activated carbon>adsorption time>particle size,respectively.Three different quality grades of crude baijiu(B,C,D)were selected to validate the orthogonal experimental results.The results showed that using activated carbon to treat the crude baijiu under optimized experimental conditions can effectively improve the sensory quality of the crude baijiu.At the same time,through the validation of the aging time models of crude baijiu,it was found that the crude baijiu samples treated with activated carbon are equivalent to the natural aged crude baijiu that has been stored for more than 6 months,which once again confirms the effect of activated carbon in removing impurities and promoting aging.(3)Combining the activated carbon artificial impurity removal and aging technology with the traditional storage aging research of Baijiu,the influence of ceramic containers and stainless steel containers on the quality of Nongxiangxing baijiu after the activated carbon impurity removal and aging treatment was compared with that of natural storage aging Baijiu samples.The experiment shows that both storage methods can optimize the taste of the crude baijiu,thereby improving the quality of the crude baijiu,and the storage effect of ceramic containers is better than that of stainless steel containers.Under the optimized experimental conditions for removing impurities and accelerating aging,the quality of the crude baijiu treated with activated carbon remained stable during a short period of storage of 5 months,which was equivalent to the natural aging of the crude baijiu for more than 10 months,.In conclusion,the using of activated carbon to remove impurities and promote aging of Nongxiangxing crude baijiu,combined with the storage of ceramic containers,can shorten the aging time of crude baijiu,effectively improve the quality of the crude baijiu,and the promotion and application in production will generate considerable economic benefits... |
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