Exploring ultrasound combined with Litsea pungens Hemsl essential oil compound coating for modulating flavor and metabolites in Nuodeng ham: A multidimensional analysis by UHPLC-QE-MS and GC-IMS

The mechanism of ultrasound (US) combined with Litsea pungens Hemsl essential oil (LO) compound coating on Nuodeng ham was investigated at defined power levels, including LO (0 W), L-US (low, 200 W), M-US (middle, 400 W), and H-US (high, 600 W). The differences in color, texture, volatile flavor substances, and metabolic networks among treatment groups were resolved by GC-IMS and UHPLC-QE-MS. The results indicated that both L* and a* values in the LO group were notably higher than those of the control group (CG), whereas the H-US group showed a significant reduction in hardness. The flavor analysis revealed that the compound treatment enhanced the flavor substances, including hexanal and 2-heptanone. A total of 67 differential metabolites were identified, confirming that the treatment promoted the accumulation of flavor metabolites through the regulation of amino acid metabolism, TCA cycle, and lipid metabolism. These results provide a theoretical basis for fermented meat processing.