Abstract:The polypeptide compositions of three enzymatic hydrolysis products of skipjack tuna were studied, and the peptide segment length was identified using liquid chromatograph-tandem mass spectrometry peptidomics. The results revealed 2 395 peptide segments identified from three components, among which 266 and 1 342 peptides were identified from peptides consisting of 3~7 and 8~25 amino acids, respectively. Most identified peptides contained 8~18 amino acids. The ion scores of peptides with 3~7 amino acids were -0.207~207, whereas the most scores were in the range of 20.7~124. The ion scores of peptides with 8~25 amino acids ranged from 29 to 517, with the majority between 29 and 224. The correlation between each component was greater than 0.8, indicating a strong correlation. Glutamate acid showed the highest polypeptide content in the enzymatic hydrolysate of skipjack tuna. Myosin heavy chain contributed the largest number of peptide segments. Myosin heavy chain and α-actin exhibited a relatively high protein abundance. Flavor prediction was performed for some peptide segments with high ion scores. LVEEELD was the most frequently detected umami amino acid fragment, with a frequency of 1.428 6. This fragment contained multiple active segments, such as D, E, EE, EEE, EL, EEL, and VE, and had high taste richness. Some bitter amino acids were constituents of umami peptides, whereas sour and sweet amino acids also contributed to the umami taste. Finally, adding the enzymatic hydrolysate of skipjack tuna to other seasoning products influenced the flavor. These results provide a theoretical basis for the development of seasonings related to skipjack tuna.
