Role of extraction procedures on the concentration of varietal thiol precursors in Grillo white grape must

Background and Aims Varietal thiol precursors (VTPs) decrease strongly after the pre-fermentative operations. The effect of grape must extraction steps on concentration S-3-(hexan-1-ol)-L-glutathione (G-3SH), S-3-(hexan-1-ol)-L-cysteine (Cys-3SH) S-3-(hexanal)-glutathione (G-3SHal) was investigated. Methods Results Must produced a commercial scale sampled throughout pre-fermentation steps. also prepared in laboratory for assessing role copper, sulfite air. In fractions, over 95% G-3SHal lost because addition, while G-3SH Cys-3SH increased along with yield, it exceeded found berries. No intact grape; instead trace G-SHal, high glutathione even cysteine determined when added. A large amount formed copper depleted. Conclusions Our data suggest that are promptly mainly upon pressing. Sulfite prevented formation VTPs, settling led to loss VTPs. Significance Study can be preserved through proper management pressing particular attention contact air, conditions, time solids addition sulfite.