Abstract: 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.

Key words: mulberry fruits, vacuum freeze\, drying, vacuum degree, drying time, sample throughput