Impact of dealcoholization on quality properties in white wine at various alcohol content levels

The reduction of alcohol content in wines has two main objectives, the former is decreasing the wines' strength and the latter is producing new low alcohol beverages. To accomplish the latter, in this study, we focused on the dealcoholization of a white wine (cv Falanghina, 12.5 vol%) obtained from an ancient Italian grape variety that has recently aroused a renewed interest. It was dealcoholized at various alcohol content levels ranging from 9.8 to 0.3 vol% through the osmotic distillation process, and the main quality parameters of the obtained dealcoholized samples were evaluated. No significant differences (p < 0.05) in total phenols, flavonoids, organic acids and total acidity were observed among the wine samples at different alcohol content levels. On the contrary, the volatile compounds content decreased with increasing alcohol removal. Specifically, almost 50% of higher alcohols with acids and lactones were preserved in dealcoholized wine at 9.8 vol% alcohol content, but this percentage reduced to 30% in the sample at 6.8 vol%, and was even lower in the dealcoholized wine with lower alcohol content. It was argued that the transport of volatile compounds through the membrane, beside the membrane selectivity, is highly correlated with the Henry constant (R² > 0.8021 for 9.8 vol% of dealcoholized wine). Moreover, results of the sensory evaluation indicated a significant change in terms of acidity, odour, sweetness and body taste in dealcoholized wine (0.3 vol%), giving an overall perceived imbalance and unacceptable taste with respect to the original wine. Therefore, in order to balance acid sensation and enhance body and aftertaste, an attempt was made to formulate an alcohol-free wine-based beverage with enhanced odour and sweetness, by adding some floral wine flavours, up to the amount present in the original wine.