Metabolic remodeling and proteolysis enhancement during dual‐stage sonication assisted co‐fermentation to improve liver pâté qualities

BACKGROUND: Physical-field-assisted bioprocesses have recently been employed to improve the quality and flavor of meat products, but the microbial metabolic mechanisms associated with multistage treatment during mixed-culture fermentation remain insufficiently understood. In this study, yeast and lactic acid bacteria were used for the co-fermentation of lamb liver pâté, and a two-stage ultrasound strategy (RLTUS) was introduced, consisting of ultrasound pretreatment before fermentation and secondary ultrasound stimulation during fermentation. The effects of this combination process on physicochemical properties, textural characteristics, and metabolomic changes were evaluated. RESULTS: Compared with CK, RLTUS treatment significantly increased the proteolysis index and total free amino acid content by 36.05% and 22.24%, respectively, while reducing the thiobarbituric acid reactive substances value by 25.92% after fermentation. In contrast, hardness and chewiness decreased by 34.97% and 56.12%, respectively. Moreover, flavor-related amino acids, including the umami amino acids aspartic acid and glutamic acid as well as the sweet amino acids alanine and glycine, accumulated significantly, contributing to enhanced flavor development. Untargeted metabolomics detected a total of 2037 metabolic features, and principal component analysis clearly separated the RLTUS group from the other treatments, indicating the strongest metabolic remodeling effect. Further analysis revealed significant enrichment of pathways including arginine and proline metabolism, lysine degradation, glycerophospholipid metabolism, and tryptophan metabolism. CONCLUSION: Dual-stage ultrasound-assisted co-fermentation enhanced substrate utilization and accelerated flavor-precursor release and transformation. This study provides a theoretical basis and technical support for the high-value utilization of livestock by-products and the development of novel fermented meat products. © 2026 Society of Chemical Industry.