Combined membrane process for dealcoholization of wines: Osmotic distillation and reverse osmosis

The demand of beverages with low or zero alcohol content is fast growing over the last years for health benefits of drinkers and more restrictive policies in alcohol consumption. Membrane processes are nowadays the most commonly used. They have undoubtedly led to improvements in quality, particularly for the low processing temperatures, but determined volatile compounds loss which in many instances resulted in unsatisfactory sensory quality. This study evaluates the combination of two membrane processes for the production of lower alcohol wines: osmotic distillation (OD) and reverse osmosis (RO). It aims for retain the flavour, preserve the good taste of wine with low alcohol content. A red wine (13.2 %v/v) was reduced in alcohol strength of about -5, -6, -8 %v/v through a RO and OD combined process: the initial wine was firstly treated through RO and was subsequently processed through OD to obtain partial dealcoholized wines. Such wines were then compared with those obtained through OD technique. Low alcohol wines were analysed for chemico-physical parameters and volatile composition. The results showed a better retention of the main chemical properties and volatile compounds in wines with low alcohol content obtained through the combined OD and RO process than those through single OD.