Determination of microwave drying and rehydration kinetics of green peppers with the bioactive and textural properties

Abstract

The aim of this study was to determine the effect of microwaves on drying and rehydration kinetics of green pepper varieties (sweet, green, and bell) and the bioactive and textural properties of dried and rehydrated peppers. Drying was performed at 90, 180, and 90 + 180 W and dried peppers were rehydrated at 25, 50, and 70 degrees C. The best drying fits were obtained using the equations of both Sigmoid and Hii et al. for drying, and two term exponential decay was the most appropriate model for rehydration. The lowest and highest final rehydration ratio values were obtained for the peppers dried at 180 and 90 W, respectively at each temperature and pepper variety. Among peppers, bell pepper showed the lowest color change (Delta E) and it was the most potent to recover initial color in rehydration. Peppers had softer texture in both drying and rehydration treatment. Total phenolic content of peppers was reduced around 56-65% compared to the fresh pepper by drying and this decrement was reached up to 87% in rehydrated peppers. Results showed that drying at 180 W and rehydration at 70 degrees C provided faster drying and rehydration as well maintained the quality characteristics of green peppers.