Preparation and antioxidant activities of oligosaccharides from Crassostrea gigas

Abstract Oligosaccharides were prepared from Crassostrea gigas by hydrolysis of polysaccharide in C. gigas with peroxide oxygen (H 2 O 2 ). The hydrolysates were cleared of protein, filtered, ultrafiltered and precipitated with absolute ethanol to give C. gigas oligosaccharides (CGOs). Factors affecting CGO yields, i.e., reaction time, temperature, and H 2 O 2 concentration, were optimised as follows: 2.96 h reaction time, 84.71 °C reaction temperature, and 2.46% H 2 O 2 concentration. Under these conditions, the maximum yield of CGOs reached 10.61%. The CGOs were then partially characterised by Fourier transform infrared spectroscopy, UV spectroscopy, monosaccharide composition, and antioxidant activities. Results indicate that CGOs possessed strong hydroxyl radical activity, 2,2-diphenyl-β-picrylhydrazyl-radical-scavenging activity and reducing capacity at a concentration of 100 μg/mL.