采用真空冷冻干燥方法确定冻干米饭的最佳工艺参数,并分析比较快速冻结和慢速冻结两种方法对冻干米饭的影响。结果表明:在冻结温度-50℃、时间1.5h;一次干燥温度-20℃、时间8h,二次干燥温度50℃、时间5.5h;真空度维持在10Pa左右的条件下工艺最佳,并绘制了冻干曲线。而且从综合品质和营养角度上分析,快速冻结的产品具有更高的品质,附加值高。
In this study, the processing parameters of vacuum freeze-drying for instant rice were explored. The slow frozen and the rapid frozen rates were analyzed and compared. Results indicated that the optimal processing parameters for vacuum freeze-drying of instant rice were primary stage freezing temperature of -50 ℃, freezing time of 1.5 h; drying temperature of -20 ℃, frozen time of 8 h; second stage drying temperature of 50 ℃, frozen time of 5.5 h; final stage frozen temperature of -50 ℃, frozen time of 1.5 h; the vacuum pressure of 10 Pa. Results indicated that rapid frozen could provide higher product quality based on the analysis of comprehensive quality and nutritional components.