Release kinetics of Tilapia scale collagen I peptides during tryptic hydrolysis

Collagen was extracted from the scales of Tilapia (Oreochromis niloticus) and characterized by using sodium dodecyl sulfate (SDS) -polyacrylamide gel electrophoresis and size exclusion chromatography. Liquid chromatography-tandem mass spectrometry analysis confirmed the collagen as Oreochromis niloticus type I collagen. During 8 h of digestion, 65 and 62 peptides were identified from collagen alpha 1 subunits and alpha 2 subunits, respectively. Trypsin, preferentially cleaved two terminal hydrophilic regions of collagen subunit alpha 1 and alpha 2. The rate of release of peptides from the tryptic initial hydrolysis of both collagen alpha 1 and alpha 2 subunits was faster than that of peptides during further tryptic cleavage. Sequence overage of the peptides released from the enzymatic hydrolysis of collagen alpha 2 subunits remained higher than those of collagen alpha 1 subunits, which coincides with the fact that the degree of hydrolysis (DH) of enzymatic hydrolysis of collagen alpha 2 subunits was greater than that of the enzymatic hydrolysis of collagen alpha 1 subunits. The patterns of peptide release from different reaction times can guide the food production process to ensure safety. However, the identified peptide from the hydrolysates can be used as markers to evaluate peptide food and then produce high-quality peptide food. (C) 2017 Elsevier Ltd. All rights reserved.