ATR-FTIR Microspectroscopy as a Tool for Distinguishing Wine-Relevant Saccharomyces spp. Strains Based on Their Autolytic Behavior

Yeast autolysis significantly impacts the final composition and sensory profile of wine, particularly in wine styles where postfermentation contact with yeast lees is encouraged. The release of macromolecules from yeast cells during autolysis is influenced by both the winemaking conditions and the intrinsic properties of the yeast strain. In this study, FTIR microspectroscopy in ATR mode coupled with multivariate statistical analysis was employed to monitor the autolytic process in YPD medium by analyzing the biochemical changes in the external cell structures of selected wine-relevant yeast strains: Saccharomyces cerevisiae EC 1118, FR-B, and CH, and Saccharomyces bayanus Q20. FTIR microspectroscopy allowed differentiating EC 1118 and FR-B from CH and Q20 based on the kinetics of the autolytic process mainly involving mannans and beta-1,4 and beta-1,6 glucans. As such, it has the potential for integration into the fine-tuned screening of starter cultures for biotechnological applications.