Comparison of the physicochemical and volatile composition of wine fractions obtained by two different dealcoholization techniques.

•Membrane contactor and vacuum distillation were used for wine dealcoholization.•Polyphenols concentration increased in the wine fractions dealcoholized at 5% v/v.•No precipitation of potassium bitartrate was observed during dealcoholization.•The main compositional modifications occurred with the wine aroma compounds.•Using the fractions to dealcoholize wines by 2% slightly modified the δ18O ratio.