Impact of the composition of polysaccharide composite gels on small molecules diffusion: A rheological and NMR study

The gelation mechanism of carrageenan depends on the amount and nature of the polysaccharide, and is cation sensitive. From a rheological approach, this specificity leads to different textural properties. In composite gels with carrageenans, starch and sucrose, the presence of κ/κ2-carrageenan, even at low levels, has an impact on textural and structural properties. In this study, rheological and diffusion NMR measurements were performed on composite gels to probe gel structure at the macro- and micro-scale. Variations were made in the gel composition by varying the carrageenan content and the nature of the polysaccharide and cations. We showed that all the factors that increased the rigidity of the composite gels – polysaccharide content and specific cations – decreased significantly the diffusion of small molecules such as sucrose and ethyl butyrate.