Studies On Processing Technology Of Hulun Buir Blueberry Juice

Making blueberry juice from blueberry can solve the problem that blueberry fresh fruit is not storable,but it is easy to have problems such as low juice yield,poor clarity and poor storage stability in the process of blueberry juice processing.This experiment optimized the blanching time,enzymolysis process(enzymatic hydrolysis time,enzymatic hydrolysis temperature,enzyme addition amount and compound enzyme ratio)and clarification process(chitosan solution addition amount,clarification temperature,p H value)conditions of blueberry juice.The effects of three sterilization methods(high pressure processing,pasteurization and high temperature short time pasteurization)on microbial indicators,anthocyanin content and ascorbic acid content and storage stability were investigated.The results showed that at 95℃,the optimal blanching time of 300 s could significantly increase the juice yield rate of blueberry and reduce the activity of polyphenol oxidase.The optimum enzymolysis conditions were enzyme addition 0.2%,ratio of complex enzyme(pectinase: cellulase)2.9:1,enzymolysis temperature 52℃,and enzymolysis time 2 h.Under these conditions,the juice yield of blueberry juice was79.58±1.12%.The best clarification conditions are the addition of chitosan solution 0.63g/L,clarification temperature 46℃,p H 3.53,and the clarity of blueberry juice was83.55±0.23 %.Combined with the analysis of the sterilization effect of the sterilization method on blueberry juice and the retention of anthocyanin and ascorbic acid content,the best sterilization method for blueberry juice was ultra-high pressure sterilization technology(HPP,600 MPa,5 min).In addition,after high pressure processing,blueberry juice could still meet the requirements of commercial sterility during 8 weeks of storage at4℃,and the anthocyanin content was maintained at 170.21 μg/m L(preservation rate was51.91%),and the ascorbic acid content was maintained at 19.91 μg/m L(preservation rate was 52.45%).The contents of total acid,reducing sugar and soluble solid had no significant change(p >0.05).In this study,the processing technology of blueberry juice was improved by optimizing blanching time,enzymolysis process,clarification process and sterilization method,which provided a basis for the industrial production of high-quality blueberry juice.