White wine dealcoholization by osmotic distillation: An experimental study and impact on key quality parameters

Abstract

This study aimed at investigating the impact of the osmotic distillation (OD) process parameters, including feed and stripping flow rates, on the removal of ethanol from white wine for the production of dealcoholized wine (0.5% v/v ethanol). The research evaluated the dealcoholization kinetics and ethanol mass transfer behavior using mathematical modeling, alongside investigating the impact of different ethanol levels on physico-chemical parameters, color profile and volatile composition of the wine. The results showed that without renewing the stripping solution, ethanol reduction stabilizes after several dealcoholization cycles due to an equilibrium between ethanol content in the feed and stripping side. However, renewing the stripping solution increased ethanol removal rates, facilitating the production of dealcoholized wine. Additionally, variations in feed and stripping flow rates without renewing the stripping solution, in the range of investigated values, did not significantly impact the ethanol removal rate. The total weight loss during the production of dealcoholized wine (0.5% v/v) was 20.7%. Partial dealcoholization (up to 4.6–5.0% v/v) showed minor changes in physico-chemical parameters of wine, while full dealcoholization at 0.5% v/v resulted in changes in acidity, pH, several non-volatile compounds and color of wine. The reduction in total volatile compounds showed a positive correlation (r = 0.93) with ethanol removal, in particular for the loss of esters (reduced by 89%), alcohols (78%), acids (86%), carbonyl compounds (96%) and volatile phenols (88%).