Effect of different NaCl concentrations on the structure-function relationship of citrus peel pectins modified by electrochemistry

Abstract

In this study, the modified citrus peel pectins (CPPs) were successfully produced by electrochemistry with varying NaCl concentrations of 0, 0.01 % and 0.1 % w/v using an H-type cell at 40 mA current. After 4 h, the pH and oxidation-reduction potential (ORP) of oxidized CPP solution in the anodic region were 2.00– 2.52 and 371.17– 564.45 mV, respectively, due to the electrolysis of water, whereas those of reduced CPP solution in cathodic region were 9.46– 10.84 and − 202.77 ∼ −230.57 mV. The modified CPPs in the anodic region (A-0, A-0.01, and A-0.1) exhibited significantly higher weight-average molecular weights and methyl esterification degrees than those in the cathodic region (C-0, C-0.01 and C-0.1). In contrast, the K+, Mg2+, and Ca2+ contents of A-0, A-0.01, and A-0.1 were lower than those of C-0, C-0.01 and C-0.1 due to the electrophoretic migration. Furthermore, the antioxidant activities of A-0 and A-0.01 solutions were stronger than those of the C-0, C-0.01, and C-0.1, while rheological and texture properties of their hydrogels showed contradictory results. Finally, the potential structure-function relationships of CPPs were explored by combining PCA and correlation analysis. Overall, this study introduced a potential approach for pectin purification and functional low-methoxyl pectin manufacturing.