Preparation and properties of the pectic gel microparticles based on the Zn, Fe and Al cross-linking cations.

The aim of this work was to evaluate the relationship between the cross-linking cation content in the microparticles, chemical characteristics of pectins and swelling properties of the gel microparticles based on the Zn, Fe and Al cross-linking cations. A significant negative correlation between the Zn content and DM of pectin indicated that decreasing DM of pectin promoted Zn binding. The microparticles from the pectins with a higher linearity had a higher content of Fe. The microparticles from the pectins with a lower Mw, branching of rhamnogalacturonan I, amount of RG, specific viscosity and a higher linearity had a higher content of Al. The content of the Fe ions in the microparticles was higher than the Zn content. The Al content in the microparticles was lowest. The Fe and Zn ions, which are more electronegative, bind more strongly to pectin in comparison with the less electronegative Al cations. The microparticles with a higher Zn, Fe, and Al content had a lower swelling degree in the simulated digestive fluids. Moreover, the higher swelling of the microparticles can be due to their porous or wrinkled surface. Variation of specific cations and pectins can influence the functionality of the gel microparticles, in particular swelling properties.