Abstract:

Polysaccharides from Enteromorpha prolifera were prepared in our laboratory and degraded with trifluoroacetic
acid (TFA) in smaller molecules. The antioxidant activity of the degradation products was evaluated in terms of hydroxyl
radical scavenging activity. Using orthogonal array design, we established the optimal degradation conditions to be treatment
with 1.0 mol/L TFA at 80 ℃ for 5 hours with a solid-to-liquid ratio of 1:200 (g/mL). Under these conditions, the yield of
degradation products was 40.05%. The hydroxyl radical scavenging rate of the degraded polysaccharides reached 61.83%, with
an IC50 of 0.3521 mg/mL compared to 1.8940 mg/mL for the intact polysaccharides, suggesting these degradation products
have significantly higher antioxidant activity. Moreover, the intrinsic viscosity (60.618 mL/g) of the intact polysaccharides was
reduced to 22.789 mL/g after the degradation, and the average relative molecular weight (1.19 × 105) was lowered to 6.41 × 104.

Key words: polysaccharides from Enteromorpha prolifera, degradation, hydroxyl radical scavenging activity