Microwave drying of bitter yam (Dioscorea bulbifera): An approach of MATLAB image processing to comprehend moisture diffusion process

Abstract

AbstractThis study examined how microwave power loading (300–600 W) affected Dioscorea bulbifera (BY) slice drying, colorimetric values, moisture diffusion, textural, and rehydration properties. Drying time was reduced from 100 to 40 min with increased microwave power from 300 to 600 W. Drying rate and moisture diffusivity (4.948 × 10−9–1.262 × 10−8 m2/s) enhanced with microwave power and was observed falling rate drying. The initial and final moisture content of BY slices were 87% (w.b.) and 4.5% (w.b.), respectively. The activation energy for BY slices was 9.6 W/g. To illustrate the drying and color change behavior of BY, experimental data were fitted to 10 dryings and 4 color kinetics models. The Midilli–Kucuk model and the Fraction model were the best fitted for moisture and color parameters. The highest efficiency was 55.85% and the lowest specific energy consumption was 9.6 MJ/kg at 600 W microwave power. MATLAB microstructure characterization provided detailed pore analysis of microwave‐dried samples.Practical ApplicationsMicrowave‐dried yam can enhance storability, ease handling and transportation and protect against microbial activity, enzymatic browning and high‐water activity. Mathematical modeling of pretreated microwave‐dried yam is useful for industrial dryer design and large‐scale yam drying production. Additionally, yam flours have the potential for use in numerous applications, including noodles, extrudates, cookies, and bakery products. Further, yam flour may be a binder, thickener, and gelling agent.