响应面法优化板枣热风-真空分段联合干燥工艺

为探讨分段联合干燥对板枣干燥特性和品质的影响及优化干燥工艺,以热风温度、转换点含水率、真空温度为实验因素,以典型品质参数(V_C含量、总糖含量、色泽、游离氨基酸总量)及干燥效能(干燥时间、能耗)为研究指标。并进行响应面工艺优化,获得联合干燥最佳的联合方式。结果表明:热风干燥阶段最佳的干燥温度为64.50℃,转换点含水率为52.50%,真空干燥温度为65.00℃。此条件下干燥后的板枣V_C保留了26.89%,总糖含量为85.21%。干燥耗时为23.00 h,与单一热风干燥耗时(29.00 h)相比减少了20.68%,与单一真空干燥耗时(25.00 h)相比减少了10.00%左右,干燥能耗为2.45 kW·h,大于单一真空干燥能耗(1.48 kW·h),但仅为单一热风干燥能耗(6.01 kW·h)的40.00%。

Optimization of Hot Air-vacuum Segment-combined Drying Process of Jishan Jujube by Response Surface Method

In order to study the effect of segment-combined drying on the characteristics and quality of Jishan jujube,and optimize the drying process,the hot air temperature,the switching point,vacuum temperature were used as the experimental factors to study the typical quality parameters(V_C content,total sugar content,color,total amino acids)and the drying efficiency(drying time and energy consumption). Then the response surface process was optimized to obtain the best drying method of hot air-vacuum segment-combined drying. The results were as follows:The best drying temperature of hot air drying stage was 64.50℃,and the best switching point was 52.50%,and the best vacuum drying temperature was 65.00℃. Under these conditions,the V_C of dried Jishan jujube retained 26.89% and the total sugar content was 85.21%. The drying time was 23 h,which was 20.68% less than that of single hot air drying(29.00 h). Compared with single vacuum drying(25.00 h),the drying time reduced by about 10%. The energy consumption was 2.45 kW·h,higher than the single vacuum drying(1.48 kW·h),but only 40% of single hot air drying(6.01 kW·h).