Optimization of Infrared-Hot Air Combined Drying Process of Stevia rebaudiana Bertoni

In order to explore the infrared-hot air drying characteristics of Stevia rebaudiana Bertoni,the Stevia rebaudiana Bertoni No.3 in Jiangxi province was used as the experimental material,and the hot air temperature(90,100,110,120 ℃),wet power(0,140,240,340 W)and radiation distance(140,150,160,170 mm)were developed by single-factor and orthogonal experiments on the basis of the developed infrared-hot air combined drying prototype. The infrared-hot air drying characteristic curve and drying rate curve of Stevia rebaudiana Bertoni were explored,and the drying process parameters of Stevia rebaudiana Bertoni were optimized. The results showed that the Stevia rebaudiana Bertoni infrared-hot air combined drying process included preheating accelerated drying stage and deceleration drying stage. The influencing factors affecting the production efficiency of Stevia rebaudiana Bertoni infrared-hot air combined drying were:Hot air temperature > radiation distance > dehumidification rate. The best drying process parameters:Hot air temperature 120 ℃,moisture discharge power 240 W,radiation distance 140 mm,at this time Stevia rebaudiana Bertoni drying time 6.57 min,energy consumption 1.25 kW·h.This study could provide a reference for the development of Stevia rebaudiana Bertoni drying equipment and the study of the drying characteristics of Stevia rebaudiana Bertoni.