Metschnikowia pulcherrima as biocontrol agent and wine aroma enhancer in combination with a native Saccharomyces cerevisiae

One of the main objectives for a sustainable winemaking process is the reduction of the use of sulfur dioxide. Inthis regard, non-Saccharomyces wine yeasts are proposed as biocontrol agent in different steps of wine productionchain. Here, a selected strain of Metschnikowia pulcherrima (DiSVA 269) and a native Saccharomyces cerevisiae lowsulfite producer strain (DiSVA 708) were investigated. After preliminary laboratory trials, winemaking process atindustrial level showed an effective biocontrol action (reduction of c.a. 1 Log order of wild yeasts) ofM. pulcherrima inoculated at prefermentative stage in cold clarification (48 h at 10 ◦C) and during the subsequentfermentation process. The combination of M. pulcherrima/S. cerevisiae led a distinctive aromatic profile of winesboth in laboratory and winery trials with a significant enhancement of ethyl butyrate, ethyl hexanoate, isoamylacetate and β-phenyl ethanol. Moreover the use of the two selected strains was the best combination to enhancevolatile thiols (3-mercaptohexan-1-ol and 3-mercaptoexil acetate) that well correlate with the sensory analysis(tropical fruits). The overall results indicate that the combined use of M. pulcherrima DiSVA 269 and nativeS. cerevisiae DiSVA 708 led a biocontrol action and an improvement of aromatic and sensorial profile of wine withlow SO2 content.