The gelation behavior of thiolated citrus high-methoxyl pectin induced by sodium phosphate dibasic dodecahydrate

The present study found that sodium phosphate dibasic dodecahydrate (Na2HPO4) was capable of inducing the gelation of thiolated citrus high-methoxyl pectin (TCHMP). TCHMP was synthesized by amidation of citrus high-methoxyl pectin. The gel formation exhibited an obvious concentration-dependence, including TCHMP and Na2HPO4 concentration. For Na2HPO4-induced TCHMP gels (TCHMPGs), gel strength and water holding capacity (WHC) increased, while the microcellular network structure was more compact with the increase of TCHMP and Na2HPO4 concentration. Dynamic viscoelastic experiment showed when Na2HPO4 concentration was more than or equal to 0.5 mol/L, TCHMP sols could be transferred into gels within 30 min. Crystal property was not changed while thermal stability was improved after phase transition. Gelling forces analysis indicated that disulfide bonds were the main interaction forces in TCHMPGs. Consequently, TCHMPGs were covalently crosslinked and exhibited satisfactory gel performance. The results provide a theoretical basis for the formation of gels by Na2HPO4 induced TCHMP.