Integrated multi-omics analysis deciphers the molecular mechanisms underlying the characteristic volatile flavor of Meishan pork

Background The Meishan pig is a celebrated indigenous Chinese swine breed renowned for its distinctive flavor profile. However, the specific signature flavor compounds and the molecular mechanisms underlying their formation remain largely uncharacterized. This study aimed to comprehensively profile the volatile flavor compounds across five pig breeds and decipher the molecular basis of the characteristic flavor of Meishan pork. Results Comparative analysis combining electronic nose, headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and relative odor activity value calculations revealed that Meishan pork contained significantly higher levels of four key aroma compounds: hexanal, nonanal, 2-pentylfuran, and (E,E)-2,4-nonadienal. Integrated metabolomic and transcriptomic analyses identified oleic acid and α-linolenic acid as critical precursors and highlighted the high expression of the arachidonate 5-lipoxygenase gene ( ALOX5 ) in Meishan pigs. Heating experiments confirmed that these fatty acids yield characteristic flavor compounds upon thermal oxidation. Furthermore, functional studies demonstrated that ALOX5 catalyzes the conversion of these precursors into flavor aldehydes. Conclusions The distinctive flavor of Meishan pork is associated with a dual mechanism: thermal oxidation of abundant precursors during cooking, and enhanced enzymatic oxidation prior to cooking resulting from constitutively high ALOX5 expression. By deciphering the flavor formation mechanism from metabolic precursors to enzyme-catalyzed conversion, this investigation provides a framework for elucidating meat flavor chemistry and offers potential targets for breeding strategies aimed at improving pork flavor.