Investigating the effects of pre-treatment, drying techniques and packaging on nutritional quality and shelf-life of pomegranate arils

Abstract

This study investigated the influence of harvest maturity stage, pretreatment (blanching and unblanched), and drying methods (sun drying and oven drying) on the drying time, physicochemical qualities, nutritional value, microbial load and shelf life of dried pomegranate arils. Blanching emerged as a critical step that accelerated drying time, minimized colour change and phenolic content retention differently in sun and oven drying methods compared to the unblanched counterpart. The findings suggest that early harvest and blanching can substantially reduce drying time, which is beneficial for large-scale production. Unblanched arils required a drying period of 10–12 days when exposed to direct sunlight, whereas blanched arils only needed 2–3 days. Unblanched arils required a drying time of 10–12 h in the oven (at air temperature of 60 °C and velocity of 0.5 m s −1 ), whereas blanched arils took 6–7 h for drying under the same conditions. Early mature arils dried faster. Blanching reduces the rate of TPC loss for oven drying but not sun drying. We observe a decrease in antioxidant activity and total flavonoid concentration for the sun-dried aril compared to oven dried aril. Sun and oven-dried arils stored at 20 °C, and 65% relative humidity had an estimated shelf life of 633 and 668 days, when packed in HDPE plastic film and 78 days and 118 days without packaging, respectively. • Blanching accelerates drying time significantly. • Early harvest reduces drying time. • Sun drying decreases antioxidant activity. • Blanched arils retain phenolic content better. • Packaging extends arils' shelf life dramatically.