(1.College of Life Sciences, Northeast Forestry University, Harbin 150040, China) (2.Spice and Beverage Research Institute of Chinese Academy of Tropical Agricultural Sciences, Key Laboratory of Processing Suitability and Quality Control of the Special Tropical Crops of Hainan Province, Woody Grain Germplasm Resource Center of National Tropical Plant Germplasm Resource, National Center of Important Tropical Crops Engineering and Technology Research Wanning, Hanan 571533, China) Find this author on AllJournals Find this author on Google Scholar Find this author on BaiDu Find this author on PubMed Search for this author on this site
Water-soluble pectin (WSP), chelate-soluble pectin (CSP), and sodium carbonate-soluble pectin (SSP) were extracted from breadfruit and their physicochemical properties, structural characteristics, and antioxidant activities were analyzed and compared. The results showed that WSP was characterized by high viscosity (145.80 mPa•s), high molecular weight (1241.3 ku), and high degree of esterification (86.33%). CSP was characterized by low viscosity (17.88 mPa•s), low molecular weight (218.6 ku), and low degree of esterification (45.73%), while SSP was characterized by a high extraction rate (47.73%), good solubility (96.20%), low viscosity (4.63 mPa•s), and low molecular weight (186.3 ku). The main monosaccharide compositions of the three kinds of pectin were rhamnose, arabinose, galactose, glucose, xylose, and galacturonic acid. The results of Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) indicated significant differences among the three types of pectin. The antioxidant results showed that the scavenging ability of WSP, CSP, and SSP on hydroxyl free, ABTS+ free and DPPH free radicals increased with the increase in mass concentration of each pectin. SSP had the strongest radical scavenging activity, reaching a scavenging rate of 96.56% of ABTS radicals at a concentration of 0.5 mg/mL. In conclusion, SSP pectin exhibited good antioxidant activity due to its small molecular weight, rich branched chains, low viscosity, and smooth surface.
