Concentration of pomegranate juice by forward osmosis or thermal evaporation and its shelf-life kinetic studies

Abstract

Pomegranate (Punica grantum L.) fruit juice was concentrated by forward osmosis or thermal evaporation and the samples were stored at ambient (25 °C) and accelerated (37 °C) storage conditions. The anthocyanin content of raw, reconstituted forward osmosis as well as reconstituted thermally evaporated pomegranate juice were 421.1, 414.4 and 357.2 mg/kg respectively. The physicochemical attributes of pomegranate juice concentrate such as anthocyanin content, antioxidant activity, browning index, and hydroxymethyl furfural showed that the quality of the concentrate was markedly affected by storage conditions. Based on the hydroxymethyl furfural content (≤25 mg/kg), it was concluded that the forward osmosis concentrated juices could be stored at ambient and accelerated conditions for ∼101 and ∼66 days, respectively. While, thermally concentrated juice could only be stored for less ∼31 and ∼3 days, respectively. Forward osmosis could be a method to concentrate pomegranate juice with minimum effect on quality attributes with extended shelf life.