关键词: 山楂, 冻融, 果汁, 黄酮, 优化, 响应面

Abstract: To obtain hawthorn fruit juices with high nutrition value and strong health function, freeze-thawing softening technology combined with enzymatic extraction was applied for the preparation of hawthorn fruit juices, and the optimum preparation conditions for the highest content of total flavonoids of hawthorn fruit juice was obtained by using Box-Benhnken center-united experiment design and response surface methodology. The results indicate that pretreatment with freeze-thawing can improve the enzymatic extraction of flavonoids from hawthorn fruit, and thereby it is favorable for the preparation of high-flavanoids hawthorn fruit juice. Among the factors which influence the contents of flavonoids in hawthorn fruit juices prepared by using freeze-thawing softening combined with enzymatic extraction technology, the duration and temperature for enzymatic extraction as well as freezing time affected the contents of flavonoids in hawthorn fruit juices significantly (p＜0.05), while the amount of enzyme had minor effect upon them. The optimum conditions for freeze-thawing-enzymatic preparation of high-flavonoids hawthorn fruit juice was freezing for 9.93h followed by enzymatic extraction for 2.14h at 59.36℃ with addition of 0.97mL/kg pectinase. Under this condition, the content of flavonoids in hawthorn fruit juice was 243.18mg/100g as predicted according to the regression model, which agreed well with the experimental values.

Key words: hawthorn, freeze-thawing, fruit juices, flavonoids, optimization, response surface methodology