The attention of some winemakers and researchers over the past years has been drawn towards the partial or total dealcoholization of wines and alcoholic beverages due to trends in wine styles, and the effect of climate change on wine alcohol content. To achieve this, different techniques have been used at the various stages of winemaking, among which the physical dealcoholization techniques, particularly membrane separation (nanofiltration, reverse osmosis, evaporative perstraction, and pervaporation) and thermal distillation (vacuum distillation and spinning cone column), have shown promising results and hence are being used for commercial production. However, the removal of alcohol by these techniques can cause changes in color and losses of desirable volatile aroma compounds, which can subsequently affect the sensory quality and acceptability of the wine by consumers. Aside from the removal of ethanol, other factors such as the ethanol concentration, the kind of alcohol removal technique, the retention properties of the wine non-volatile matrix, and the chemical-physical properties of the aroma compounds can influence changes in the wine sensory quality during dealcoholization. This review highlights and summarizes some of the techniques for wine dealcoholization and their impact on wine quality to help winemakers in choosing the best technique to limit adverse effects in dealcoholized wines and to help meet the needs and acceptance among different targeted consumers such as younger people, pregnant women, drivers, and teetotalers.

Non-Saccharomyces (NS) yeasts with high β-glucosidase activity play a vital role in improving the aroma complexity of wines by releasing aroma compounds from glycosidic precursors during fermentation. In this study, the effect of sequential inoculation fermentation of Meyerozyma guilliermondii NM218 and Hanseniaspora uvarum BF345 with two Saccharomyces cerevisiae strains [Vintage Red™ (VR) and Aroma White™ (AW)] on volatile compounds and sensory characteristics of wines was investigated. Prior to winemaking trials, the sequential inoculation times of the two NS yeasts were evaluated in synthetic must, based on changes in strain population and enzyme activity. The intervals for inoculation of NM218 and BF345 with the S. cerevisiae strains were 48 and 24 h, respectively. In the main experiment, sequential inoculation fermentations of the two strains with S. cerevisiae were carried out in Cabernet Sauvignon (CS) and Chardonnay (CH) grape must. The oenological parameters, volatile composition, and sensory characteristics of the final wines were assessed. No clear differences were observed in the oenological parameters of the sequentially fermented CH wines compared with the control, except for residual sugar and alcohol. However, in CS wines, the total acid contents were significantly lower in the wines fermented by sequential inoculation compared to the control. Both NM218 and BF345 improved the aroma complexity of wines by increasing esters and terpenes when inoculated with S. cerevisiae strains compared to inoculation with S. cerevisiae strains alone. NM218 resulted in a more positive effect on CS wine aroma, with higher levels of citronellol and trans-nerolidol. BF345 significantly enhanced the floral and fruity aromas of CH wine by producing higher concentrations of geranyl acetone, β-damascenone, trans-nerolidol, and nerol. Both NM218 and BF345 yeasts could potentially be used to improve wine aroma and overall quality, especially wine floral and fruity aromas, when used in sequential inoculation with S. cerevisiae.

Using Chardonnay grape, the fermentation characteristics of sequential inoculation with M. guilliermondii and S. cerevisiae in the pilot fermentation process of dry white wine were examined. In this study, the physical and chemical indexes, color indexes, volatile aroma compound composition, and sensory indexes of 2 tons of samples at the end of alcoholic fermentation (AF) and malolactic fermentation (MLF) were analyzed. The results showed that the M. guilliermondii biomass in the treatment group (inoculated M. guilliermondii and S. cerevisiae sequentially) was always higher than 106 CFU/mL during AF, and the basic physicochemical indexes of samples met the requirements of the national standard GB/T15038-2006 (Wine). Also M. guilliermondii NM218 can significantly increase the color saturation of Chardonnay white wine. Regarding aromatic characteristics, the total alcohol, ester, and terpene contents of wine samples after mixed fermentation were higher than those of control group (only inoculated S. cerevisiae). Compared with control wine samples (only with S. cerevisiae), the treatment group had significantly increased ethyl caprylate, ethyl nonanoate, phenethyl acetate, and ethyl laurate contents, including n-heptanol, which can provide Chardonnay dry white wine a richer fruity fragrance. meanwhile, the sensory scores of wine samples were higher in the treatment group. In conclusion, mixed fermentation could boost the aroma quality and sensory pleasure of dry white wine, with the potential for industrial application.