The Effect of Selected Fruit (Apple, Bitter Orange and Grape) Juice Concentrates Used as Osmotic Agents on the Osmotic-Dehydration Kinetics and Physico-Chemical Properties of Pomegranate Seeds

Abstract

This work aimed to study the osmotic-dehydration kinetics of pomegranate seeds (PSs) (Punica granatum L.) using three fruit (apple, bitter orange and grape) juice concentrates as osmotic solutions (OSs) (ratio (1/4) m/v, 55° Brix, at 50 °C). The osmodehydration time, pomegranate-seed water loss, solute gain and weight reduction were determined during the osmodehydration process. The equilibrium time periods of osmodehydration were 20, 60, 80 and 60 min for sucrose solution, and bitter-orange, apple and grape juice concentrates, respectively. The physico-chemical, biological and textural properties of PSs were significantly affected by the changes in OS. At the end of osmodehydration, the dry-matter and the Brix values were higher in all fruit-based OSs compared with sucrose OS. The color of PSs became darker in apple and grape OSs and brighter in bitter-orange OS compared with sucrose OS. On the other hand, all osmodehydrated PSs showed important antioxidant activity, with seeds osmodehydrated in grape-juice OS attaining an IC50 of 49.25 meq GA/100 g DM. All observed changes were attributed to the difference in the composition of the different OS matrices. Moreover, the hedonic analysis showed that consumers preferred osmodehydrated PSs obtained using bitter-orange juice as OS.