Mechanisms and effects of non-Saccharomyces yeast fermentation on the aromatic profile of wine

Microorganisms, particularly yeasts, play key roles in the complex process of grape wine fermentation. Saccharomyces cerevisiae is the yeast species primarily utilized in alcoholic fermentation and it has, thus, been the subject of extensive research. However, it is difficult to enhance the aroma type (such as varietal, fermentation and aging aromas) or complexity of wine when it is fermented using Saccharomyces cerevisiae and, hence, the alternative use of non-Saccharomyces yeasts has increased in wine production. Moreover, in the quest to further control the physicochemical characteristics and sensory qualities of wine, the different influences of non-Saccharomyces yeasts and Saccharomyces cerevisiae on the types and contents of wine flavoring substances, such as esters, terpenes, higher alcohols and phenolic acids, has become a hot topic of research. In this study, the effects of commonly used non-Saccharomyces yeasts on the flavor- and aroma-producing compounds active during and after wine fermentation, the mechanisms involved therein, and the interactions between different yeasts during mixed fermentation were examined. Moreover, the potential of non-Saccharomyces yeasts as a specialized inoculant was highlighted to guide the development of wines with improved aromas.