Drying kinetics and moisture migration mechanism of yam slices by cold plasma pretreatment combined with far-infrared drying

Abstract

The aim of this study was to evaluate the effects of a cold plasma (CP) pretreatment on the energy consumption, drying characteristics, and physicochemical parameters of yam slices at different temperatures during the far-infrared drying (IRD) process. The outcomes demonstrated that CP greatly increased drying efficiency while consuming less energy. At 60 °C, the drying time of yam slices with thicknesses of 3 mm, 5 mm, and 7 mm was shortened by 16 min, 24 min, and 32 min respectively. 5 mm thick yam slices during cooperative drying at 60 °C showed improved color retention which △E was only 5.09, the retention of bioactive components improved 20.5%. The loss of free water predominated and the degree of binding between moisture and material tightened as the drying time increased. MRI images showed that the proton density of the cooperative drying method disappeared faster, the moisture dropped rapidly from the center of the yam slice, followed by the edge of the yam. In general, the results showed that IRD + CP had a broad potential in improving the drying efficiency and product quality of the food industry.