莴笋渗透脱水有效扩散系数研究

以葡萄糖溶液浓度(10%～40%)和温度(35～65℃)为影响因素,研究了莴笋渗透脱水的动力学过程。分别使用Azuara模型和Fick第二扩散定律计算出了平衡时刻的失水率、固形物增加率以及相应的水分和固形物有效扩散系数。设计了均匀实验,通过曲面拟合的方法得到了水分、固形物有效扩散系数与因素的回归方程。结果表明:失水率随着葡萄糖溶液浓度增加而增大,但随着温度的升高而降低;固形物增加率随着溶液浓度和温度的增加而增加。Azuara模型可用来预测失水率和固形物增加率,通过曲面拟合得到的有效扩散系数回归方程拟合性较高。有效扩散系数反映了失水率和固形物增加率达到平衡时刻的快慢程度。

Study on effective diffusion coefficients of osmotic dehydration of asparagus lettuce

The mass transfer kinetics during osmotic dehydration of asparagus lettuce was investigated in glucose solution with concentration between 10%～40% and temperature between 35～65℃.Rates of water loss and solid gain at equilibrium as well as effective diffusivity coefficients were calculated by Azuara model and Fick’s second law respectively.Regression equations of effective diffusivity coefficients of water loss rate and solid gain rate were obtained based on surface fitting by a uniform design.The results showed that water loss rate increased with the increasing of glucose concentration,but it reduced with the increasing of temperature.Both the increasing of solute concentration and temperature enhanced solid gain rate.Azuara model was fit for predicting values of water loss rate and solid gain rate.And a high degree of correlation was observed in regression equations of effective diffusion coefficients by surface fitting.Effective diffusion coefficients represented the rates of water loss and solid gain approaching equilibrium.