Osmotic distillation applying potassium pyrophosphate as brine

Potassium pyrophosphate was applied as stripping solution in osmotic distillation of fruit juices. The permeate ranged between 0.56 and 1.45 kg/m2h, being more sensitive to the variation of the feed temperature. After pre-saturating the experimental apparatus, no significant effect on the degradation of ascorbic acid was found and the losses of volatile compounds were no larger than 62% while 100% of the aroma compounds were lost during thermal concentration. In addition, orange juice was concentrated from 10 to 27 °Brix and the process did not change the physicochemical characteristics of the final juice. In conclusion, potassium pyrophosphate can advantageously substitute calcium chloride as the stripping solution of osmotic distillation in the concentration of fruit juices, allowing brine reconcentration using direct contact evaporation with flue gas.