Influence of Cryoextraction and Cold Pre-Fermentative Maceration on the Yeast Microbiota and the Volatile Compounds Profile of Sangiovese Wine

Abstract

Low-temperature treatments can be applied to grapes or must before alcoholic fermentation to enhance the wine’s sensory characteristics. Several studies have shown that such practices have a positive effect on the polyphenol profile of the wine, but only a few surveys have examined the effect of these treatments on the yeast microbiota of grapes and wine. Therefore, this study aimed to evaluate how cryoextraction (freezing the grape with liquid nitrogen) and cold pre-fermentative maceration (at 5 °C for 48 h) affect the Saccharomyces and non-Saccharomyces populations during the winemaking process of red grapes, cv Sangiovese, conducted at two temperatures (20 and 30 °C). This research analyzed the concentration of various yeast species, their fermentation abilities, and the resulting wine’s aromatic profile. The Principal Component Analysis performed on yeast concentrations during the fermentations of various wines did not group the experimental wines based on treatment. However, the same groupings were highlighted when the concentrations of the volatile compounds, quantified in the experimental wines, were processed using the same statistical approach. Therefore, cryoextraction and cold pre-fermentative maceration seem to contribute less to the aromatic profile than the yeasts involved in the fermentation process.