莴苣真空渗透脱水的二次回归正交旋转组合试验

Experiments on lettuce vacuum osmotic dehydration of quadratic regression orthogonal rotation combination design

为获得莴苣真空渗透脱水的较优工艺参数,以莴苣为原料,通过试验研究了渗透温度、切片厚度、真空度和蔗糖浓度4个因素对莴苣真空渗透脱水过程的影响;其失水率和固形物增加率随着切片厚度和真空绝对压力的增大而减少,随着渗透温度和蔗糖浓度的增大而增大。运用二次回归正交旋转组合设计方法建立了莴苣真空渗透脱水的失水率和固形物增加率回归数学模型,模型相关系数值分别为0.912和0.904。最后利用多目标非线性优化分析法对莴苣真空渗透脱水工艺进行了综合优化;优化结果表明,在试验范围内,莴苣真空渗透脱水的较优工艺参数为:切片厚度2 mm、渗透温度28℃、蔗糖浓度47%和真空度22 kPa,此时,失水率为72.16%,固形物增加率为11.82%。

In order to obtain the optimal technological parameter of the lettuce vacuum osmotic dehydration, the effects of vacuum degree, slice thickness, solute liquid concentration and temperatureon the lettuce osmotic dehydration at vacuum pressure were explored by using lettuces as an experiment raw material. The lettuce dehydration and solid gain rate decreased with increasing slice thickness and vacuum absolute pressure, and increased with increasing solute liquid concentration and temperature. The regression mathematical models of lettuce dehydration and solid gain rate were established by applying the method of quadratic regression orthogonal rotation combination design, and the model correlation coefficients were 0.912 and 0.904 respectively. Finally, the technological parameters of lettuce vacuum osmotic dehydration were optimized comprehensively by the analysis of multi-objective nonlinear optimization. The results indicated that, within the experimental scope, the optimized technological parameters of lettuce vacuum osmotic dehydration are the 2 mm slice thickness, 22 kPa vacuum degree, 47% solute liquid concentration and 28 ℃ temperature, and the lettuce dehydration and solid gain rate are 72.16% and 11.82% respectively.