以桑葚为试材,比较了热风干燥和真空冷冻干燥对桑葚果粉品质的影响。结果表明:真空冷冻干燥桑葚果粉得率和含水率低于热风干燥果粉,但溶解性能优于后者,电镜下观察到真空冷冻干燥果粉颗粒大,颗粒间孔隙较多结构疏松,热风干燥果粉颗粒间聚集紧密孔隙较少,真空冷冻干燥果粉Vc、总酚、花色苷的保留率分别为97.97%、98.40%和96.36%,而热风干燥桑葚果粉Vc、总酚、花色苷等物质保留率分别为37.47%、92.07%和69.13%,损失比较严重,真空冷冻干燥可较完好地保持桑葚原有品质。

The quality of two kinds mulberry powders produced by hot air drying and vacuum freeze drying were compared. The results illuminated that both yield and moisture content by vacuum freeze drying were lower than hot air drying,but vacuum drying showed a better solubility. The images taken by the scanning electronic microscope showed the particles of vacuum freeze drying powder were more porous and larger in comparison with the hot air drying. The retention ratio of Vc,total phenol,and anthocyanin of vacuum freeze drying powder was 97. 97%, 98. 40%,96. 36% respectively,while hot air drying powder was much lower at 37. 47%,92. 07%,69. 13%,respectively. Therefore,vacuum freeze drying is better in maintaining the quality of mulberry powder.