腐竹微波干燥工艺优化及其动力学研究

Study on the optimization of microwave drying process of yuba and its dynamic

为保证腐竹品质、提高干燥效率,采用微波技术干制鲜腐竹。通过响应面法优化腐竹微波干燥工艺,并建立干燥动力学模型。结果表明:腐竹微波干燥过程包含升速、恒速和降速3个阶段,恒速干燥是鲜腐竹中水分蒸发的主要阶段,此阶段持续时间越长,腐竹品质越好;在微波功率700 W、载样量1100 g、间歇时间1.2 min的最佳工艺条件下,腐竹复水比为2.75±0.21,色差为4.32±0.27,单位能耗为0.156 kJ/g±0.0795 kJ/g。腐竹微波干燥过程的有效水分扩散系数范围为(0.771~1.540)10^(-10)m^(2)/s,属于较快的食品水分蒸发速率。与5种经典干燥模型拟合分析发现,Page模型与试验数据拟合度最高。

In order to ensure the quality of yuba and improve the drying efficiency,microwave technology was used to dry fresh yuba.The microwave drying process of yuba was optimized by the response surface methodology,and then a dynamic model was established.The results showed that the microwave drying process of yuba included three drying stages such as increasing speed stage,constant speed stage and decreasing speed stage.And the constant speed drying stage was the main stage of fresh yuba water evaporation.The longer the constant speed drying stage lasted,the better the quality of yuba was.Under the optimal process conditions of microwave power of 700 W,loading capacity of 1100 g,and intermittent time of 1.2 min,the rehydration ratio of yuba was 2.75±0.21,the color difference was 4.32±0.27,and the unit energy consumption was 0.156 kJ/g±0.0795 kJ/g.The effective moisture diffusion coefficient of yuba under microwave drying was(0.771-1.540)×10^(-10)m^(2)/s,which was a relatively fast evaporation rate in food drying.The fitting analysis with 5 classical drying models showed that the Page model had the highest fitting degree with the experimental data.