Effects of different pre-fermentation cold maceration time on aroma compounds of Saccharomyces cerevisiae co-fermentation with Hanseniaspora opuntiae or Pichia kudriavzevii

The positive influence of mixed fermentation by S. cerevisiae and non-Saccharomyces yeast species on wine aroma quality is well recognized. In this study, the effects of different pre-fermentation cold maceration time (1, 3 and 7 days) on aroma compounds co-fermented by S. cerevisiae with non-Saccharomyces yeast species, Hanseniaspora opuntiae or Pichia kudriavzevii, were investigated. The results showed that in all cases, the changes of cold maceration (CM) time strongly affected aromatic compounds formation, but clear species-dependent difference was observed. Compared to pure S. cerevisiae fermentation, prolong CM time (3 d and 7 d) in Sc/Ho mixed fermentation could generate higher amount of higher alcohol (phenylethanol and 3-methyl-butanol), phenylacetaldehyde and intensify the floral and sweet attributes of wine. Moderate extending CM time (3 d) in Sc/Pk mixed fermentation increased the formation of 3-methyl-butanol, ethyl acetate and isoamyl acetate, and decreased the concentrations of C6 alcohols and fatty acids (decanoic acid and octanoic acid). These results highlighted the role of nutrient status in grape must on the regulation of aromatic compound formation, and also suggest that changing pre-fermentation CM time combined with mixed fermentation could be a potential way to manipulate aromatic composition and increase the aromatic quality and complexity of wine.