Degradation by Vc‐H 2 O 2 , characterization and antioxidant activity of polysaccharides from Passiflora edulis peel

Abstract

In this paper, water extracted polysaccharides from Passiflora edulis peel (WPEP) was degraded by ascorbic acid-hydrogen peroxide (Vc-H2O2). The degradation conditions were optimized by response surface methodology (RSM). The 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate of degraded WPEP (DWPEP) was 45.38% under optimal conditions (Vc-H2O2 concentration 9.3 mM, temperature 52°C, time 1.4 hr). And the molecular weight (Mw) of DWPEP (38 kDa) was 32.20% (WPEP was 118 kDa). WPEP and DWPEP were mainly composed of galacturonic acid. Their backbone structures, functional groups and β-glycoside linkage patterns are similar, however, still with some differences. Antioxidant tests showed that WPEP and DWPEP had strong DPPH radical scavenging ability (93.03% and 81.70%), moderate hydroxyl radical scavenging ability (53.99% and 26.59%), and low reducing power (0.698 and 0.52). In conclusion, these differences in structures and properties may be an important factor affecting the antioxidant activity of polysaccharides. Novelty impact statement In this paper, the Vc-H2O2 system was used to degrade the polysaccharides extracted from Passiflora edulis peel. The molecular weight, intrinsic viscosity, and rigid conformation changed obviously. The degraded polysaccharides are valuable to expand their application and to improve the practical efficacy.