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

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 C 13 -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. [ABSTRACT FROM AUTHOR]