基于品质和能耗的杏鲍菇微波真空干燥工艺参数优化

Optimized technology of Pleurotus eryngii by microwave-vacuum drying based on quality and energy consumption

为了提高杏鲍菇干制产品品质,降低干燥能耗,该文应用微波真空技术干燥杏鲍菇。采用三元二次回归旋转组合设计方法进行工艺参数优化试验,考察分析微波强度(X1)、物料厚度(X2)、腔体绝对压力(X3)因素对品质指标色差(Y1)、复水比(Y2)、氨基酸含量(Y3)和单位能耗(Y4)的影响及因子间交互作用对指标的影响;采用线性加权法,将多目标综合优化,确定干燥工艺的最优参数组合。结果表明:微波强度、物料厚度、腔体绝对压力对试验指标色差、复水比、氨基酸含量、单位能耗影响显著,物料厚度是影响色差的主要因素,物料厚度小于2 cm时,产品色泽较差;腔体绝对压力是影响复水比和氨基酸含量的主要因素,较小的腔体绝对压力有利于产品复水和减少氨基酸损失;微波强度是影响单位能耗的主要因素,高的微波强度,能耗较高,高的微波强度与较小的腔体绝对压力组合时,干燥能耗更高;杏鲍菇微波真空干燥高品质低能耗的最优工艺参数组合为微波强度12.5 kW/kg、物料厚度2.4 cm、腔体绝对压力18 kPa,此条件下干燥的产品品质优良,色泽洁白,色差L为78,复水性好,复水比为1.58,氨基酸破坏少,其值为473.1 mg/100 g,单位能耗较低,为9.3 kJ/kg。

Microwave-vacuum experiments ofPleurotus eryngii were conducted in order to improve the quality of products and decrease the drying energy consumption. The effects of microwave power density （X1）, material thickness （X2）, absolute pressure chamber （X3） and the interaction of these three factors on color （Y1）, rehydration ratio （Y2）, amino acids （I13） and unit energy consumption （I14） were investigated in this study. The process parameters were optimized through the quadratic orthogonal rotary combination design with three factors and three levels. Linear weighting method was used to analyze comprehensive multi-objective optimization. The regression equations of four indexes were developed based on the experimental data and the optimal combination in process were obtained. The results showed that there were significant impacts of color, rehydration ratio, amino acids of Pleurotus eryngii and unit energy consumption from power density, material thickness and absolute pressure chamber. The major factor affecting on the color of Pleurotus eryngii was material thickness. The color of Pleurotus eryngii was poor when material thickness was less than 2 cm. The major factor affecting on rehydration ratio and amino acid of Pleurotus eryngii was absolute pressure chamber. The smaller absolute pressure chamber was beneficial to rehydration of dried Pleurotus eryngii and reduced the loss of amino acid of Pleurotus eryngii during drying. Microwave power density was the major factor affecting on the unit energy consumption. The energy consumption was high when Pleurotus eryngii was dried at high microwave power density. The combination of high microwave power density and small absolute pressure chamber could cause even higher energy consumption. The microwave power density of 12.5 kW/kg, material thickness of 2.4 cm and absolute pressure chamber of 18 kPa were the optimized parameters of microwave-vacuum dried Pleurotus eryngii with high-quality and low-energy consumption. Their product quality was excellent, the color was white （the value of color difference was 78）, rehydration ratio （1158） was appropriate, amino acids （473.1 mg/100 g） was less damaged, and unit energy consumption （9.3 kJ/kg） was lower.