Properties of Protein Hydrolysates and Bioinformatics Prediction of Peptides Derived from Thermal and Enzymatic Process of Skipjack Tuna (Katsuwonus pelamis) Roe

Currently, the use of skipjack tuna (Katsuwonus pelamis) roe to produce hydrolysate is limited, although it is a potentially valuable resource. This study aimed to investigate the physical and chemical characteristics of protein hydrolysates from tuna roe using autoclave and enzymes (alcalase and trypsin at 0.5 and 1.0% w/v). Bioinformatics was also applied to analyze the identified peptides. The hydrolysates were determined for amino acid composition, peptide profile patterns, antioxidant activity, solubility and foaming properties. The proteins were separated by SDS-PAGE before tryptic digestion and peptide identification by nano LC-ESI-MS/MS. The putative bioactivities of the identified peptides were predicted using bioinformatics prediction tools. The main amino acids found in all hydrolysates were cysteine, glycine and arginine (16.26-20.65, 10.67-13.61 and 10.87-12.08 g/100 g protein, respectively). The hydrolysates obtained from autoclaving showed lower molecular weights than those by the enzymatic method. The 0.1 g/mL concentration of hydrolysates provided higher antioxidant activities compared to the others. All hydrolysates had high solubility and exhibited foaming capacity and foam stability. Putative anti-hypertensive, anti-virus and anti-parasite activities were highly abundant within the obtained peptides. Moreover, predicted muti-bioactivity was indicated for seven novel peptides. In the future work, these peptides should be experimentally validated for further applications.