Stable isotope ratios and aroma profile changes induced due to innovative wine dealcoholisation approaches

The high ethanol level in wine has become an important issue for all the main wine producing countries. Several techniques are available to the wine industry to reduce the ethanol content; among them, the membrane contactors are certainly one of the newest. Very few studies on the effect of this practice on the wine quality and aroma profile and on the stable isotopes composition are available. A pilot and industrial plant equipped with the membrane contactor system were used in the study in the dealcoholisation on several white and red wines. Significant changes for several classes of aroma compounds in both pilot- and industrial-scale experiments were observed, even though these changes were not always in perfect agreement with the sensory evaluation carried out. Finally, modifications on the δ18O of up to 1‰ for 2 %v/v and of up to 4‰ for 8 %v/v ethanol removal were encountered. An increase of δ13C of ethanol of up to 1.1‰ for 2 % and of up to 2.3‰ for 4 % of dealcoholisation rate was also observed. Dealcoholisation via membrane contactor seemed to affect the overall wine composition (aroma and flavour), even though the main concern resided on the alteration of the isotopic composition which could be linked to product authenticity issues.