Comparative study of quality changes occurring on dehydration and rehydration of cooked chickpeas (Cicer arietinum L.) subjected to combined microwave-convective and convective hot air dehydration

Convective hot air dehydration (100 degrees) of cooked chickpeas was compared with the combination of microwave-convective hot air dehydration, in terms of microstructure, density, color, texture, dehydration, and rehydration. In the combined drying experiments, 2 levels of microwave power (100 W and 200 W) were investigated combined continuously with convective air drying at 100 degrees C. Compared with convective hot air drying, combination drying led to a considerable reduction in dehydration time. Combination drying also improved the porosity of the finished dehydrated product, leading to faster rehydration kinetics. Cryogenic scanning electron mircoscopy micrographs showed that the chickpeas subjected to a combined drying experienced less shrinkage than those dryed by convective hot air. Combination drying at the higher (200 W) level produced a darker (p < 0.05) rehydrated product with significantly lower relative rehydrated moisture content (p < 0.05) when compared with the lower (100 W) level of combination drying.