Optimization of intermittent microwave drying technology for lees by response surface methodology

The intermittent microwave drying experiments were conducted to optimize the lees drying process and improve its quality after drying. Taking drying rate, energy consumption and quality as target parameters, the three factors were scored by using the comprehensive evaluation of the membership-degree method. According to the central composite experimental design principle, the response surface methodology was adopted to discuss the influence caused by microwave power, lees thickness and pulse ratio. In addition, the quadratic polynomial regression model was established to optimize the drying techniques. The results showed that effects order of three factors on lees drying were as follows: pulse ratio first, lees thickness second, and then microwave power. The optimal parameters of intermittent microwave drying method for lees were microwave power of 480 W, lees thickness of 2.78 cm and pulse ratio of 6.625, then the largest comprehensive score of 0.723 was obtained. The study provides a theoretical basis for further study on microwave drying equipment and technology for lees.