Industrial avocado waste: Functional compounds preservation by convective drying process

Abstract

A convective drying process was optimized as strategy to produce dehydrated ingredients with high antioxidant capacity; using Hass avocado byproducts (peels and seeds). Studied processing variables were: temperature (45 °C–75 °C), air-flow (0.8 m/s to 1.8 m/s) and loading density (1 kg/m2 to 3 kg/m2). The response variables were Total Phenol Content (TPC) and Antioxidant Capacity (DPPH). Drying kinetic analysis revealed that seeds had higher water diffusivity than peels, but the latter showed shorter drying times. Multiple optimization routines allowed maximizing simultaneously DPPH and TPC. Thus, 62.82% and 54.81% of the initial TPC was retained in dehydrated peels and seeds, respectively. Sorption isotherms for both dehydrated byproducts showed that avocado seeds were more hygroscopic than peels, which was attributed to differences on their composition. This research has outlined a useful tool for the transformation of avocado wastes into storable commodities with high antioxidant properties which may have different food uses.