Optimization for pectinase-assisted extraction of polysaccharides from pomegranate peel with chemical composition and antioxidant activity

In this work, based on response surface methodology (RSM), an optimized method of extracting water-soluble polysaccharide from pomegranate peel (PPP) with pectinase was proposed. Additionally, the chemical composition and the antioxidant activities of the extracted PPP were studied. The effects of three factors of enzymolysis time, ratio of liquid to solid and dosage of enzyme on the PPP yield were investigated. The experimental results showed that the optimal conditions were as following: enzymolysis time 19.70 min, ratio of liquid to solid 20.5:1(mL/g), dosage of enzyme 0.68%. Under the best conditions, the maximum PPP yield was 27.3 ± 0.08%. FT-IR and GC-MS revealed that PPP was the typical acidic heteropolysaccharides and mainly consisted of d-mannose (19.30%), d-galactose (47.93%) and l-arabinose (23.08%). Moreover, the antioxidant activity assay in vitro showed that PPP exhibited strong reducing power and good scavenging activities on superoxide anion, hydroxyl, and DPPH radicals. The PPP extracted with pectinase had excellent antioxidant properties and could be developed into a new type of dietary supplement or functional food.