Preparation and characterization of aminoethyl hydroxypropyl starch modified with collagen peptide

The preparation of aminoethyl hydroxypropyl starch collagen peptide (AEHPS-COP) was via an enzyme-catalyzed reaction between amino groups in aminoethyl hydroxypropyl starch (AEHPS) and γ-carboxamide groups in collagen peptide (COP) by using microbial transglutaminase (MTGase) as biocatalyst. As an intermediate reactant, AEHPS was synthesized from hydroxypropyl starch (HPS) and 2-chloroethylamine hydrochloride (CEH). The chemical structures of HPS, AEHPS and AEHPS-COP were characterized by Fourier transform infrared spectroscopy (FT-IR) and ¹³C nuclear magnetic resonance (¹³C NMR). The reaction conditions that influenced the degree of substitution (DS) of AEHPS-COP were optimized, which included the reaction temperature, the reaction time, the mass ratio of collagen peptide to aminoethyl hydroxypropyl starch and the pH value. In addition, in vitro antioxidant activities of AEHPS-COP were evaluated through the scavenging activity of hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Furthermore, the methylthiazol tetrazolium (MTT) assay was applied to investigate the cell viability of AEHPS-COP. The results indicated that the AEHPS-COP exhibited better cell viability to L929 mouse fibroblast cells. Therefore, the AEHPS-COP showed a promising potential application in cosmetic, biomedical and pharmaceutical fields.