Alternate microwave and convective hot air application for rapid mushroom drying

The objective of the study was to develop an integrated drying system for optimal drying of button mushroom. Microwave (MW) was decided to be applied alternatively with convective hot air. Judicious application of microwave was decided by analysing the slope of the drying curves at every 10, 20 and 40 min of convective drying. The optimal time of MW application was found to be 20 ± 3 min based on minimum drying time and better quality attributes. The experiments were then performed on slice thickness of 2.5, 5 and 10 mm under optimal conditions (MW at 21st, 42nd, 63rd and 84th min of drying) and compared with conventional hot air drying in terms of drying kinetics, colour, water activity and rehydration ratio. The optimum thickness was found to be 2.5 mm which met the quality standards of commercial dried mushroom in relatively shorter time (72 min).