Untargeted metabolomics coupled with chemometrics for flavor analysis of Dahongpao oolong tea beverages under different storage conditions

The stability of flavor in ready-to-drink tea beverages has been a pressing concern for the tea beverage industry. This study aimed to investigate the flavor quality changes in Dahongpao oolong tea beverages stored under different conditions (4 degrees C and 37 degrees C) using ultra-high-performance liquid chromatography coupled with ultrahigh-performance liquid chromatography-quadrupole exactive-orbitrap mass spectrometry and headspace solid phase micro-extraction-gas chromatography-mass spectrometry. The results revealed that, compared to the samples stored at 4. C, those stored at 37.C exhibited noticeable color changes, transitioning from a mellower and sweet aftertaste to a riper and coarser flavor profile, with a decrease in roasted aroma. Utilizing orthogonal partial least square discriminant analysis, 37 key taste substances were identified, including gallic acid, catechin, 3-O-p-coumaroylquinic acid, epigallocatechin gallate, and ellagic acid, which experienced changes of 358.50%, 90.35%, 207.59%, -98.98%, and 866.10%, respectively (4 degrees C -> 37 degrees C). Moreover, through chemometric analysis and relative odor activity values>1, beta-damascone, linalool, and 2-ethyl-5-methyl pyrazine were identified as key contributors, with the carotenoid-derived pathway playing a more significant role. This study provides valuable insights for understanding and addressing flavor stability in tea beverages.