EVALUATION OF FORWARD OSMOSIS AND THERMAL CONCENTRATION FOR QUALITY RETENTION OF CHERRY JUICE AND CONCENTRATE

Abstract

Concentration optimization of cherry juice to 60°Brix was evaluated with forward osmosis (FO) at 26-35°C, and thermal evaporation (TC) under high vacuum at 70°C. Sensory evaluation of juices was conducted by discrimination and descriptive tests. A 10°C increase in temperature in FO concentration increased water flux by 35% and decreased concentration time by 19%. FO yielded higher initial retention of anthocyanins and red color, and similar sensory properties compared to TC. A 12-week shelf life study at room temperature of control, FO and TC samples included analysis of brix, color, phenolics, total anthocyanin, viscosity and major anthocyanins. Stability of anthocyanins and red color in reconstituted (13oBrix) cherry juice samples did not present significant differences due to the concentration process. Anthocyanins and red color losses over time were significantly higher when juices were stored as concentrate. Additional studies on the effect of ascorbic and added flavonoids on anthocyanin stability are recommended.