Physicochemical properties and antioxidant activity of polysaccharides obtained from sea cucumber gonads via ultrasound-assisted enzymatic techniques

Abstract

The physicochemical properties and antioxidant activity of sea cucumber gonadal polysaccharide extracted by enzymatic, ultrasound and ultrasound-assisted enzymatic methods were investigated. The results showed that the total sugar and sulphate group content (69.1 g/100 g, 14.7 g/100 g) of SCGP-UAE were higher than those of SCGP-E (58.8 g/100 g, 10.6 g/100 g) and SCGP-U (62.9 g/100 g, 13.3 g/100 g). The zeta potential, molecular weight and particle size of SCGP-UAE were significantly lower than those of SCGP-E and SCGP-U (P < 0.05). Their molar ratios of monosaccharide composition were different. With the concentration of SCGP-E, SCGP-U and SCGP-UAE from 0.25 increased to 4.00 mg/mL, the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH∙), hydroxyl radical (∙OH) scavenging ability and reducing power of them were improved. In the concentration range of 0.50–4.00 mg/mL, the antioxidant ability of SCGP-UAE was higher than SCGP-E and SCGP-U. At 4.00 mg/mL, the DPPH∙, ∙OH scavenging ability and reducing power of SCGP-UAE were 12.8%, 14.6% and 9.42% higher than those of SCGP-U and 38.1%, 29.9% and 29.3% higher than those of SCGP-E, respectively. The strongest antioxidant activity of SCGP-UAE was due to the UAE method degraded SCGP chains and exposed more sulphate groups by breaking glycosidic bonds within SCGP.