Characterization and swelling properties of composite gel microparticles based on the pectin and κ-carrageenan

The aim of this research was to produce composite gel microparticles based on the pectin (campion callus culture (SVC) and commercial apple (AU) pectins) and κ-carrageenan and investigate the relationship between the characteristics and swelling properties of the composite microparticles. The microparticles were obtained using emulsion dehydration techniques with successive incubation in calcium chloride solution. A significant positive correlation between the Ca²⁺ content and the SVC concentration in gel formulations was shown. Decreasing degree of methyl esterification (DM) of the SVC pectin promoted Ca²⁺ binding in comparison with the AU pectin. Increasing concentration of the pectin promoted increasing gel strength of the composite microparticles. The higher gel strength of the composite microparticles based on the SVC pectin was probably due to the lower DM and a higher linearity in comparison with the AU pectin. The microparticle gel formulations with a higher pectin concentration had a lower swelling degree in the simulated digestive fluids. The addition of the carrageenan to the gel formulations led to an increase in the swelling degree in comparison with that without carrageenan. The correlation analysis indicated that increasing initial Ca²⁺ content and gel strength of the microparticles promoted decreasing swelling degree of the composite microparticles.