Abstract
Vast amounts of liquid food are industrially concentrated in order to reduce storage, packaging, handling and transportation costs. Vacuum evaporation is the predominant method used by the food industry to produce liquid food concentrates, despite serious drawbacks (poor product quality, high energy demand). This paper describes the research efforts to develop alternative techniques that could be applied on an industrial scale to overcome the disadvantages of currently used concentration methods. A major part of these attempts is focused on the application of osmotic membrane techniques, namely direct osmosis, membrane distillation and osmotic distillation.