Umami and umami-enhancing peptides from myofibrillar protein hydrolysates in low-sodium dry-cured Spanish mackerel (Scomberomorus niphonius) under the action of Lactobacillus plantarum

Lactobacillus plantarum was involved in producing low-salt (2%, w/w) dry-cured Spanish mackerel, and its effect on the degradation of myofibrillar protein and production of umami peptides was investigated. Results showed that the dominant microbiome of the sample was Lactobacillus plantarum, accounting for 95.7% of the microbial community. The umami peptides in this dry-cured mackerel were extracted and separated by ultra-filtration and gel filtration chromatography and further identified by Nano-LC-MS/MS. Five umami-enhancing peptides, including TFYNELRV (1040 Da), TFYNELR (941 Da), TLFQPSF (838 Da), LYANNVL (805 Da) and FAGDDAPRAVFPS (1348 Da), were identified to be derived from myofibrillar protein, and the percentage of their hydrophobic amino acid were 42.85%, 33.33%, 57.14%, 57.14% and 53.84%, respectively. The synthetic peptides of these five umami peptides showed an umami-enhancing threshold value ranging from 0.34 to 0.45 mg mL(-1) through sensory evaluation. The SDS-PAGE analysis exhibited that actin band intensity was decreased during the processing of dry-cured mackerel. Therefore, Lactobacillus plantarum has the potential to improve the hydrolysis of myofibrillar protein to produce umami peptides in dry-cured mackerel.

Automated summary

Lactobacillus plantarum is involved in the production of low-salt dry-cured Spanish mackerel and affects the degradation of myofibrillar protein and production of umami peptides. The study identified five umami-enhancing peptides and showed the potential of Lactobacillus plantarum to improve the hydrolysis of myofibrillar protein and the production of umami peptides in dry-cured mackerel.