Comparative Study on Concentration of Juices from Colourful Wild Berry Fruits by Membrane Osmotic Distillation

Concentration of fruit juices by membrane osmotic distillation (MOD) was studied. For the experiments, fresh juices were obtained from colourful wild berries: cornelian cherry, blackthorn, and whitebeam, which can be considered as valuable, highly nutritive beverages and characterized by high level of vitamins and antioxidant capacity. These beneficial properties may be preserved if mild but effective, environementally-safe membrane processes are applied for the concentration. MOD is a coupled operation of membrane distillation (MD) and osmotic evaporation (OE), where a hydrophobic membrane is used, while the osmotic agent was concentrated CaCl2 solution. As a result of our experiments, we found that high concentration was possible to reach in the fruit juices studied, while the flux was between 0.3 and 2.4 lm-2h-1. Comparing the analytical results of the fresh and concentrated juices, it has turned out that the antioxidant capacities were almost completely preserved during the concentration process.