Study on ultrasound-assisted extraction of polysaccharide from sweet potato and its antioxidation properties

The process conditions for extracting polysaccharides from Ipomoea batatas Lam.with the assistance of ultrasound were optimized by single factor and orthogonal array design methods.Using VC as a positive control, the antioxidant properties of polysaccharide from Ipomoea batatas Lam.were also studied by radicals scavenging of hydroxyl free radical (·OH) and superoxide anion free radical (O2-·) .Results showed that the optimal extraction conditions were determined as follows:extraction temperature 70℃, extraction duration 60min, material/liquid ratio 1:25 (g/mL) , and ultrasound power 350W.Under these conditions, the extraction yield of polysaccharide was 32.22%.The decreasing order of importance of the four process conditions affected polysaccharide extraction that were extraction temperature, extraction duration, material/liquid ratio and ultrasound power.The polysaccharide from Ipomoea batatas Lam.exhibited strong scavenging ·OH and O2-· abilities, and its radicals scavenging effect was weaker than VC.