Volatile organic compound dynamics in Ugni Blanc and Vidal wines during fermentation in the Hexi Corridor (China): Insights from E-nose, GC-MS, GC-IMS, and multivariate statistical models

In this study, the dynamic changes of volatile organic compounds (VOCs) in Ugni Blanc and Vidal wines during different fermentation stages in the Hexi Corridor region (China) were comprehensively investigated using a combination of GC-MS, GC-IMS, and E-nose techniques. 71 and 63 VOCs were identified through GC-MS and GC-IMS, respectively, with esters, alcohols, aldehydes, and ketones comprising the predominant compounds. The fermentation process induced significant changes in the composition and concentration of VOCs. Furthermore, E-nose analysis demonstrated effective discrimination between Ugni Blanc and Vidal wines. The orthogonal partial least squares discriminant analysis and Random Forest models were employed to analyze GC-MS and GC-IMS data, facilitating the identification of VOCs that significantly influence these wines at various fermentation stages. By combining the calculation of OAV and ROAV, 9 potential key aroma compounds were identified, including ( Z )-3-hexenyl acetate, isoamyl acetate, ethyl octanoate, ethyl laurate, 1-octanal, 1-pentanal, isobutyraldehyde, 1-octen-3-ol, and β -damascenone. This study provides valuable insights into the dynamic changes of VOCs during the fermentation of Ugni Blanc and Vidal wines, offering a foundation for improved fermentation control and enhanced wine quality.