From detail to diversity: Capturing the chemical signature of non- Saccharomyces  yeasts in white wine through GC×GC/TOF-MS metabolomics and complementary analytical approaches.
To gain a broad understanding of yeast species' effects, Malvazija istarska wines produced by sequential inoculation with five non- Saccharomyces  starters and monoculture fermentation with a  Saccharomyces cerevisiae×S. paradoxus  hybrid and a  S. cerevisiae  control were thoroughly analyzed. Two-dimensional gas chromatography/mass spectrometry, alongside conventional GC, enabled the identification of 399 volatile compounds and revealed many yeast-specific effects. Non- Saccharomyces  starters generally decreased the concentrations of acetaldehyde, 2-phenylethanol, fatty acids, and volatile phenols, while increasing the concentrations of isobutanol, its esters, and isoamyl acetate.  Torulaspora delbrueckii  had the most pronounced impact, with higher concentrations of short-chain ethyl esters and acetates, and lower levels of acetaldehyde, medium-chain acids, and their ethyl esters. The effects on terpenoids, norisoprenoids, thiols, C 6 -alcohols, ketones, lactones, and furanoids varied. Multivariate analysis revealed numerous yeast-specific volatile markers. Non- Saccharomyces  yeasts preserved more hydroxycinnamic acids. Overall, the results obtained provided an in-depth insight into the yeast-driven modulation of white wine chemical composition.
Delač Salopek D, Vrhovsek U, Carlin S, Radeka S, Tomašević M, Lukić I