LC-MS/MS-Based Metabolomics and Multivariate Statistical Analysis Reveal the Mechanism of Proteases on Myofibrillar Protein Degradation and the Evolution of Taste Compounds.

plays a key role in developing the taste of dry-cured ham, while the mechanism of proteases on myofibrillar protein (MP) hydrolysis and the evolution of taste substances has not been studied. The enzymatic characteristics, hydrolysis capacities for MPs, free amino acid contents, metabolite compositions, and taste attributes were investigated during the interactions of MPs and proteases. The proteases of (RE) and (RX) showed high hydrolytic activities at the conditions of pH 5.0~7.0 and 30~40 °C. Compared with RX, RE showed a lower Michaelis constant (Km) value and a better affinity for protein substrates. RE showed a higher capability to degrade myosin and actin compared with RX and proteases (PK). The microtopography of enzyme-treated MPs in RE presented a smoother surface and lower root mean square roughness than that in RX and PK. The total content of free amino acids significantly increased from 0.34 mg/100 mL of CK to 17.10 mg/100 mL of RE after 4 h of hydrolysis of MPs. Sixty-two metabolites were identified by LC-MS/MS, and γ-glutamyl peptides were the main components of MP hydrolysates. Sensory scores of umami, richness, and aftertaste showed the largest values in RE among these groups. Partial least squares discriminant analysis and correlation network demonstrated that γ-Glu-Lys, γ-Glu-Tyr, γ-Glu-Glu, γ-Glu-His, γ-Glu-Leu, γ-Glu-Cys, γ-Glu-Ala, and γ-Glu-Gln were positively correlated with the improvements of umami, richness, and aftertaste in RE.