热泵干制对青花椒色差和品质的影响及工艺优化

Effects of heat pump drying on chromatism and quality of Zanthoxylum L. and process optimization

为解决青花椒自然干制以及热风干制过程中极易褐变的问题,以提高干制青花椒产品品质,实验采用热泵干制技术干制青花椒。在单因素实验基础上,考察不同的热泵干制条件对干制青花椒色差及品质的影响,选取干制温度、铺放量和相对湿度为影响因素,以色差、麻味物质含量和挥发油含量为响应值,用Box-Behnken实验设计建立响应面分析模型。结果表明,干制温度对色差△E值和麻味物质含量影响最大,其次是相对湿度,最后是铺放量;干制温度对挥发油含量的影响同样最大,其次是铺放量和相对湿度;热泵干制优化后的工艺参数组合为干制温度59.30℃、铺放量为735g、相对湿度为40%,在此工艺条件下干制青花椒,其色差△E为8.10、麻味物质含量为2.40g/100g、挥发油含量7.90mL/100g,验证结果与优化结果之间的误差均小于2.00%,回归模型能较好地模拟青花椒热泵干制过程。模型预测值与实验值比较吻合,可以用来描述和预测青花椒的热泵干制进程。

In order to inhibit browning of Szechwan green peppers during natural drying and hot air drying,heat pump drying was used to improve the quality of dried Szechwan green peppers.The drying temperature,lay heavy,relative humidity of heat pump drying were selected as influencing factors to develop a response surface regression model with chromatism,numb-taste components,volatile oils as response values.The results showed that drying temperature had the maximum effects on chromatism and numb-taste components of Szechwan green peppers,followed by relative humidity and lay heavy.Besides,drying temperature also affected the content of volatile oil the most,followed by lay heavy and relative humidity.The optimized heat pump drying condition was as follows:dried at 59.30℃with 735 g lay heavy and 40%relative humidity.Under this condition,the dried Szechwan green peppers had a chromatism△E of 8.10,2.40 g/100g numb-taste components and 7.90 mL/100g volatile oils.The error between verification and optimization results was less than 2.00%,and the regression model could better simulate the drying process and therefore can describe and predict the pump drying process of Szechwan green peppers.