Formation Mechanism of Characteristic Flavor Substances in 3-Year-Old Diannan Small-Ear Pig Ham: Lipidomics and Flavoromics Study

Diannan small-ear pig (DSP) ham is known for exceptional flavor. However, the composition of flavor components and the mechanisms underlying flavor development remain unclear. In this study, we employed lipidomics, flavoromics, and ultra-high-performance liquid chromatography–tandem mass spectrometry technologies to investigate the composition and formation mechanism of DSP ham flavor compounds. On a 10-point scale, the results demonstrated that DSP ham had good flavor qualities with sensory scores of 8.6 ± 0.52 for flavor, 7.9 ± 0.57 for taste, 8.2 ± 0.79 for texture, 8.8 ± 0.42 for color, and 8.3 ± 0.48 for acceptability. A total of 1534 lipids, 80 volatile flavor compounds, and 25 free amino acids were identified in the ham, including 14 characteristic lipids and 28 characteristic flavor compounds. Triglycerides (TG) and diacylglycerol (DG), two important lipids, are broken down into free fatty acids, which are essential building blocks for flavor formation. Non-volatile sweet amino acid L-alanine and bitter amino acid L-lysine are combined with volatile components, including 1-octene-3-ol, hexanal, benzaldehyde, and octanal, to enhance the development of DSP ham flavor. Correlation analysis indicated that key lipids, including TG, DG, and phosphatidylcholines (PC), facilitate the formation of volatile compounds in DSP ham via the glycerophospholipid metabolic pathway. This study provides a theoretical reference for further research and product development of high-quality DSP ham.