# 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

## TL;DR

This study explores how combining ultrasound with Litsea pungens essential oil affects the flavor and chemical makeup of Nuodeng ham, using advanced analytical techniques.

## Contribution

The novel use of ultrasound at different power levels combined with essential oil to enhance flavor and metabolite profiles in fermented meat.

## Key findings

- LO and low-power ultrasound improved ham color and sensory qualities.
- A total of 32 flavor markers and 67 differential metabolites were identified.
- Amino acid and lipid metabolism were key pathways influenced by the treatment.

## Abstract

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.

•LO and L-US could improve the color and sensory characteristics of ham.•LO and M-US promoted the formation of flavor substances such as hexanal.•A total of 32 characteristic flavor markers and 67 differential metabolites were identified.•Amino acid and lipid metabolism were the key metabolic pathways of the Nuodeng ham.•The combination of 400 W ultrasound and LO treatment yielded the optimal result.

LO and L-US could improve the color and sensory characteristics of ham.

LO and M-US promoted the formation of flavor substances such as hexanal.

A total of 32 characteristic flavor markers and 67 differential metabolites were identified.

Amino acid and lipid metabolism were the key metabolic pathways of the Nuodeng ham.

The combination of 400 W ultrasound and LO treatment yielded the optimal result.