Effect of drying pretreatment methods on structure and properties of pectins extracted from Chinese quince fruit

Pectin was extracted from the sun-dried, lyophilized, and subcritical dimethyl ether (DME) dewatered fruits as well as fresh fruits, giving rise to fractions SP, LP, DP, and FP, respectively. The structure and properties of the pectin samples were investigated. Among all the pectin samples, LP had the highest yield (10.49%), the highest molar mass (Mw 65,120 g/mol), and the highest water holding capacity, and was the most thermally stable. In addition, LP exhibited the highest DPPH scavenging activity and reducing power. DP had the highest degree of esterification (72.95%), the lowest molar mass (Mw 45,860 g/mol), and the highest oil holding capacity. The four pectin samples had different surface morphology. At the concentration of 2.5% (w/w) in water, all four pectins presented pseudo-plastic behavior. The study provides theoretical support for the potential application of Chinese quince pectin in food field.