The contribution of indigenous non-Saccharomyces wine yeast to improved aromatic quality of Cabernet Sauvignon wines by spontaneous fermentation

Abstract

In this study, the aromatic profiles of Cabernet Sauvignon wine and the diversity of non-Saccharomyces yeast in industrial-scale spontaneous fermentation (SF) and inoculated fermentation (IF) were investigated. The wine obtained from SF had distinct aromatic profiles compared with IF wine. SF wine was characterized by a higher amount of medium-chain fatty acids, esters, terpenes (trans-rose oxide) and C13-norisoprenoids (β-damascenone), whereas IF wine featured more aldehydes and higher alcohols. Five non-Saccharomyces yeast species, including Hanseniaspora uvarum, Candida stella, Pichia fermentans, Issatchenkia orientalis and Metschnikowia pulcherrima, were isolated from SF, and their enological traits were examined in mixed fermentation with Saccharomyces cerevisiae, respectively. The mixed culture of P. fermentans and C. stella with S. cerevisiae could generate higher levels of esters, fatty acids and norisoprenoids compared to the monoculture of S. cerevisiae, and a co-culture of M. pulcherrima, I. orientalis and H. uvarum could accumulate higher amounts of higher alcohols. Our results suggested that non-Saccharomyces yeast strains greatly contributed to the fruity aroma quality of SF wine, and the mixed culture of Saccharomyces yeasts with non-Saccharomyces yeasts such as P. fermentans, C. stella or M. pulcherrima is a valuable tool to modulate the volatile profiles and improve the aromatic complexity of wine.