Influence of microwave and microwave-convective drying on the drying kinetics and quality characteristics of pomelo

The present study investigated the effects of microwave (90 and 160 W) and combined microwave-convective (90 W-55 degrees C, 90 W-65 degrees C, 90 W-75 degrees C, 160 W-55 degrees C, 160 W-65 degrees C and 160 W-75 degrees C) drying techniques on the drying kinetics, color parameters (L*, a*, b*, C, alpha degrees and Delta e), total phenolic content (TPC), and antioxidant capacity (ATC) of pomelo samples. The drying data were fitted to 10 typically used thin-layer drying models to select a suitable model for drying of pomelo. Comparing the statistical parameters of applied models, the Diffusion Approach, Midilli et al., and Page models were found to be the best-fitting models in describing drying kinetics of the pomelo samples. It was observed that the drying temperature and/or microwave power changed significantly the all color parameters, TPC, and ATC. The combined microwave-convective drying resulted in shorter drying times with higher drying rates and high-quality dried pomelo samples. Practical applications A significant improvement in the quality retention of combined microwave-convective drying of pomelo slices was achieved. This piece of work will provide a novel method to produce microwave-convective-dried pomelo fruits with a significantly improved product quality. A practical implication is that drying of pomelo slices with an optimum condition by combined microwave-convective process can be used to get a high-quality product with a higher ATC, TPC, and color.