Application of hot air-assisted radio frequency as second stage drying method for mango slices

This study applied hot air-assisted RF (HA-RF) as second stage drying method for mango slices. Hot-air drying was used as first stage drying to reduce moisture content to about 40% (w.b.), then HA-RF drying was applied as second stage drying to further reduce moisture content to 18% within 45min with 4.5 cm sample thickness (hot air temperature: 60 degrees C, electrode gap: 7.5 cm). The time for the two-stage drying process was about 5 hr, which was clearly lower than that of hot-air drying (8 hr) or vacuum drying (7 hr). HA-RF as second stage drying maintained sample overall quality very well except for minor vitamin C degradation (retention rate: 91%); Overall quality of mango slices after the two-stage drying was better than that dried by hot-air drying, and close to that dried by vacuum drying. This study demonstrated HA-RF could be used as second stage drying method for mango slices.