Effect of Different Pretreatment Methods on Drying Characteristics and Quality of Wolfberry (Lycium barbarum) by Radio Frequency-Hot Air Combined Segmented Drying

In this study, fresh wolfberry in the current season was used as the experimental material, and a radio frequency (RF)-hot air combined segmented drying process was adopted for berry preservation. Ultrasonic treatment, hot water blanching, sucrose infiltration, ultrasonic and blanching, ultrasonic and infiltration, and NaOH and NaCl solution impregnation were used for pre-treatment of combined drying. Taking natural drying and conventional Na2CO3 dewaxing treatment as the control group, the effects of different pretreatment methods on drying characteristics, quality, and microstructure of wolfberry during combined drying were investigated. The drying time after ultrasonic and blanching pretreatment was the shortest (13.5 h), which effectively retained total flavonoids (1.79 mg/g) and enhanced their antioxidant activity (I = 60.78