The dynamic changes of volatile compounds in beef high rib during the dry-aging process were investigated by using electronic nose (E-nose) and gas chromatography-olfactometry-mass spectrometry (GC-O-MS). Samples with different aging periods could be clearly distinguished by E-nose. As the aging proceeded, the content of volatile compounds increased significantly. At the 28^th day, the content of volatile compounds was 3.21 times as high as that of unaged beef. Cluster analysis was used to investigate the similarity of changes in volatile compounds, suggesting that the aging process could be separated into three stages. The first stage was from days 0 to 7; the second stage was from days 7 to 21; the third stage was from days 21 to 28. The analysis of relative odor activity value (ROAV) and aroma characteristics demonstrated that during the whole aging process, the key aroma compounds were isopentanol and ethyl hexanoate, with wine-like, malty and fruity flavors. Meanwhile, the key volatile compounds of beef samples varied from period to period. At the 28^th day, decanal and dodecanal were identified as key aroma compounds, resulting in a change in the overall flavor of beef from fruity to fatty.

The study aimed to investigate the dynamic changes of metabolites in beef high rib with different dry-aging periods by non-targeted metabolomics based on ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS). Multivariate statistical analysis and metabolic pathway analysis were performed on the metabolites. The results showed that 41 differential metabolites were identified in dry-aged beef, including 21 amino acids, 16 fatty acids, 2 nucleotides and 2 other metabolites. The types and relative contents of differential metabolites increased significantly with prolonged aging time. Five key metabolic pathways were identified, including purine metabolism; fatty acid degradation; alanine, aspartate and glutamate metabolism; arginine and proline metabolism; and the tricarboxylic acid (TCA) cycle, which could promote the formation of flavor and nutrients in dry-aged beef.