Effects of the Protein Hydrolysis on Taste Formation of Dry-cured Beef during Processing

To investigate the effects of protein hydrolysis on the taste of dry-cured beef (DB) during processing, focusing on five distinct processing phases, the analysis encompassed the assessment of protein hydrolysis index, sensory evaluation, as well as free amino acid and nucleotide contents, along with the taste active value and equivalent umami concentrations (EUC), were utilized to comprehensively evaluate the taste compounds present in DB. Results showed that the total nitrogen level initially declined and subsequently increased as processing progressed, and the levels of non-protein nitrogen (NPN) and proteolysis index (PI) demonstrated a progressively increasing trend (P<0.05). In terms of sensory attributes, umami and saltiness received the highest scores, while sweetness, bitterness, and sourness were relatively less pronounced. The content free amino acids and nucleotides, as well as the taste characteristics of flavor substances in DB revealed significant differences (P<0.05), and key umami substances identified were glutamic acid, aspartic acid, 5'-inosinic acid (5'-IMP), and 5'-guanosine monophosphate (5'-GMP). The EUC value increased significantly (P<0.05), reaching 10.5 g MSG/100 g at the mature stage. Correlation analysis revealed that the continuous protein hydrolysis positively influenced the development of the DB characteristic taste during processing. In essence, umami stands out as the defining taste characteristic, with glutamic acid, aspartic acid, 5'-IMP, and 5'-GMP playing pivotal roles. This study offers valuable insights for enhancing the technology of dry-cured beef production and accelerating the industrialization of such meat products.