Liang Chen,* Xian Luo, Zhan Cheng, Shuang Zhao, Liang Li, and Gal Kreitman
*E & J Gallo Winery, 600 Yosemite Boulevard, Modesto, CA, 95354 (liang.chen@ejgallo.com)

Many dipeptides and oligopeptides identified in fermented foods and beverages have various taste-active or taste-modulating activities that encompass all five basic taste modes plus kokumi sensation. The presence of peptides in wine and their potential bioactivities and contributions to wine oxidative stability have been examined previously. However, the diversity of endogenous small peptides in wines remains unexplored. This study describes ultra high-performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) analysis of dipeptides and polypeptides in a range of commercial wines. Four Chardonnay wines produced at a commercial scale from vintage 2022 were screened and quantified for 400 common dipeptides by a previously developed chemical isotope labeling UHPLC Orbitrap HRMS approach. A total of 285 dipeptides were identified and quantified across all four wines at varied abundances. Dipeptide data was evaluated by principal component analysis, which showed clear and significant discrimination of wines. The most abundant dipeptides were in the wine that underwent malolactic fermentation, sur lie aging, and was aged in an oak barrel. No obvious correlation between individual amino acid and dipeptide was noted. In addition, untargeted peptidomic profiling based on UHPLC Orbitrap HRMS was developed and applied to a larger set of wines, including both commercial and experimental wines, for endogenous oligopeptides. Data-dependent acquisition HRMS spectra of non-tryptic wine samples showed the presence of large numbers of oligopeptides in wines. The peptide identifications were searched against literature peptide databases to screen sensory-relevant peptides. Salt-enhancing, bitter, sour, astringent, and kokumi peptides were found in the selected wines. The results presented in this study offer new insights on wine composition and pave the way for future study investigating the quality and sensory relevance of wine peptides.

Funding Support: E & J Gallo Winery