Concentration of Colourful Wild Berry Fruit Juices by Membrane Osmotic Distillation via Cascade Model Systems

Abstract

Fresh juices of colourful wild berries: cornelian cherry, blackthorn, white beam and elderberry are considered as valuable, highly nutritive beverages and characterized by the high level of vitamins and antioxidant capacity. The concentration process of these juices by membrane osmotic distillation was studied, where only water vapour is eliminated, while the heat sensitive, valuable compounds can be preserved. To shorten the length of the concentration period, cascade model systems with 2, 3 and 4 stages were examined, using model sucrose solutions and real fruit juices. 60 °Brix of juice concentration was possible to reach, with a flux of 0.3-2.4 L m-2 h-1. Furthermore, as a result of cascade system experiments, the length of the separation could be shortened, significantly.