The pretreatment effects on the antioxidant activity of jujube polysaccharides

Pretreatment is vital to keep the bioactivities of polysaccharides. In this paper, the effects of hot water, ultrasonic and microwave extraction, as well as the effects of protein and pigment removal steps, on the antioxidant activity of water soluble polysaccharides in jujube (WSPJ) were studied. Hydroxyl free radical (OH) scavenging activity was adopted to determine the antioxidant activity of WSPJ. The results showed that OH scavenging activity of WSPJ extracted by ultrasonic wave was higher than that extracted by hot water and by microwave. Furthermore, power parameter in both ultrasonic and microwave extraction affected the OH scavenging activity dramatically. On the other hand, Sevag reagent was better than trichloroacetic acid (TCA), TCA with 1-butanol (TCA-B) and hydrochloric acid for protein removal, and H2O2 was better than active carbon for pigment removal to keep the antioxidant activity of WSPJ.