Effect of processing methods on quality of blackberry juice

摘要

The manufacture processes of clarified blackberry juice include extraction, clarification, sterilization and storage, which all affect the quality of juice including anthocyanin content in juice and light transmittance and color of juice were investigated. In the extraction stage, the use of pectinase drastically increase light transmittance from 27 to 74%, but decrease anthocyanin content by 5~22%. In the clarification stage, the juice was clarified by agents such as gelatin, chitosan and bentonite,and still-treatments at different temperatures. The results showed that the Still-treatment at -2~0°C for 6 to 8 days was the best clarification method as the light transmittance and anthocyanin preservation rate of the obtained clarified juice achieveup to 80 and 95% respectively. In the sterilization stage, the light transmittance and total anthocyanins content of clarified blackberry juice dramatically decreased by 7~13% and 25~36% with pasteurization at 90°C for 3 min. In the storage stage, theresults showed that the clarified juice was more stable when stored at 3~5°C than 23~25°C within 13 weeks.