Abstract:In order to shorten the drying process of maca slices and improve the quality of dried products, microwave vacuum drying technology was used to dehydrate maca slices. The drying characteristics and quality of maca slices obtained under different drying conditions were studied. Mathematical models were established to predict the relationship between the dry product quality and drying conditions of maca slices by stepwise regression. Comparisons were made on the microwave vacuum drying processes of maca under different conditions by weighted comprehensive evaluation. The results showed that the effect of microwave power density on the drying rate and product quality was more significant (p < 0.05). The Weibull distribution function can describe the changing pattern of moisture ratio in maca slices as a function of time during microwave vacuum drying with high accuracy (R2 > 0.99). The effective moisture diffusion coefficients of maca slices subjected to microwave vacuum drying ranged from 2.98×10-12 to 5.08 ×10-12 m2/s, and were influenced more remarkably by the microwave density. Stepwise regression analysis can accurately build a mathematical model between the dry product quality and drying condition of maca slices (R2 > 0.99). The maca slices gained the highest comprehensive assessment score when the microwave power density and drying pressure were 1.5 W/g and 300 Pa, respectively. Thus, among the selected conditions for drying, such a condition was the most suitable for microwave vacuum drying of maca slices.
