真空冷冻干燥桑葚果工艺参数优化

Optimization of vacuum freeze drying technology for mulberry fruits

以新鲜桑葚果实为材料,研究桑葚果真空冷冻干燥工艺技术,以期获得最佳的加工工艺和参数,为脱水浆果产品工业化生产提供参考。通过单因素和正交试验设计,以复水比作为考查指标,研究了真空度、干燥时间以及处理量3个因素对真空冷冻干燥桑葚果品质的影响。结果表明,3个因素中干燥时间对果实品质影响最大,处理量次之,真空度最小,得出真空度40 Pa、干燥时间21 h、处理量为90 g时为最佳工艺条件。在此干燥工艺条件下,果实复水性最好,色泽L*,a*,b*保持率都在80%以上,且抗氧化活性物质维生素C、花色苷、总酚与新鲜果相比损失较小,保留率分别为82.38%,91.79%和87.50%。真空冷冻干燥是一种适合于果蔬的干燥方式,产品在色香味与营养成分等方面都保持较好。

With fresh mulberry as raw materials,the optimal parameters of vacuum freeze drying technology were studied,so as to provide references for the industrialized production of dehydrated berries products. Through single factor test and orthogonal test,the influences of vacuum degree,drying time and sample throughput on the rehydration were investigated. The results showed that the affecting strength was in the following order： drying time 〉 sample throughput 〉 vacuum degree. The optimal parameters for vacuum freeze-drying process were 40 Pa of vacuum degree,21 h of drying time,and 90 g of sample throughput. Under this condition,freeze-drying products showed the best rehydration,and the retention of L＊,a＊,b＊were all more than 80%,and the contents of antioxidative substance such as Vitamin C,anthocyanin and total phenol did not lose much,the reservation ratio of them were 82. 38%,91. 79% and 87. 50%,respectively. So the vacuum freeze drying technology was suitable for drying of fruits and vegetables,and could keep the color,aroma,taste and nutrients of the product effectively.