Recent advances on membrane processes for the concentration of fruit juices: a review

Fruit juices have been traditionally concentrated by multi-stage vacuum evaporation, resulting in a loss of fresh juice flavors, color degradation and a cooked taste due to the thermal effects. The promising alternative is reverse osmosis concentration. However, it cannot reach concentrations larger than 25-30degreesBrix with a single-stage RO system due to high osmotic pressure limitation, which is quite below the value of 45-65degreesBrix for standard products obtained by evaporation. Technological advances related to the development of new membranes and improvements in process engineering have been proved to overcome this limitation. New membrane processes, including membrane distillation and osmotic distillation, and integrated membrane processes are still being identified and developed in concentrated fruit juice processing to improve product quality and reduce energy consumption. Recent advances and developments of the use of membrane processes for concentrating fruit juice are reviewed and discussed in this paper. Major attentions are focused on the application of new membrane processes and integrated membrane systems. (C) 2003 Elsevier Ltd. All rights reserved.