Producing crispy chickpea snacks by air, freeze, and microwave multi-flash drying

Abstract

This study aimed to obtain and characterize dehydrated chickpea snacks by sequential hydration, cooking, and drying processes. Hydration was performed at 4, 25, and 60 °C until reaching the maximum water uptake by the grains. Then, they were boiled until 80% of the grains reached firmness minor than 15 N. Cooked chickpeas were peeled and dried by three methods, air-drying (AD), freeze-drying (FD), and microwave multi-flash drying (MWMFD). The grains moisture was reduced from 1.681 ± 0.076 g/g to less than 0.050 ± 0.003 g/g and a w below 0.270. The constant drying rate was observed for all the three drying processes, followed by a falling drying rate period. MWMFD required a much shorter processing time (0.4 h) when compared to AD (10 h) and FD (15 h). The microstructure, and texture of the product were determined. Freeze-dried chickpeas were 1.2 and 2 times more porous than the MWMFD and AD samples, respectively. Micrographs showed small and uniform pores in FD samples, while MWMFD and AD samples had irregular porous matrix. MWMFD and AD samples exhibit jagged strain-force curves, characteristic of crispy foods. Therefore, MWMFD is a suitable process to obtain crispy chickpeas in short time.