Investigating the mechanism behind warmed-over flavor in prepared pork products during their shelf life using GC-IMS.

Headspace gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS) were used to investigate the potential reaction mechanism of the oxidation process that alters the volatile organic compounds (VOCs) and fatty acid content of prepared pork products during storage. GC-IMS detected a total of 38 volatile flavor compounds, of which 16 were identified as key differential markers through orthogonal partial least squares-discriminant analysis (OPLS-DA) with variable importance in projection (VIP) values ≥1. Correlation analysis with 10 fatty acids showed that oxidative decomposition of oleic and linoleic acids increased the content of hexanal, glutaraldehyde, butanal, and (E)-2-heptenal, resulting in a warmed-over flavor (WOF). These results demonstrate that lipid oxidation is the primary driver of flavor deterioration in prepared pork products. This study provides critical insights into the formation mechanism of WOF and establishes a theoretical foundation for developing effective strategies to control flavor loss in meat products.