Osmotic and membrane distillation for the concentration of tomato juice: Effects on quality and safety characteristics

The aim of this study was to evaluate the utilization of osmotic distillation, membrane distillation, and coupled operation of these systems as an alternative to the conventional thermal evaporation (CTE) technique for the concentration of tomato juice. Some physicochemical characteristics of the products obtained by different techniques were determined. The samples concentrated by membrane systems were more advantageous by means of many parameters investigated, especially for color, hydroxymethylfurfural (HMF) and furan formation. HMF and furan contents were increased up to three to four times after CM while there was no statistical change after membrane concentrations. Ascorbic add and dehydroascorbic acid levels were decreased significantly after all concentration operations. Nonetheless, as total vitamin C content, membrane systems were more advantageous compared to CTE. Sensorial evaluation also showed that, except consistence, products obtained by membrane techniques gained higher scores than thermally concentrated products.