Properties of mixed systems prepared from mixtures of carrageenans and tensoactives

Abstract

Carrageenans are a special type of polysaccharide extracted from seaweed which reveal units of galactose and variable substitution of sulfated groups. In this way they behave like polyanions. Owing to their great affinity with water, carrageenans belong to the group of hydrocolloids, in which gelatins and other gums are also included. They are used as dispersal, jelling and thickening agents, principally in the food industry. The present project studied the interaction of some fractions of carrageenans with synthetic tensoactives with the aim of understanding: 1) the formation of possible polyelectrolytetensoactive complexes; 2) the variation in the jelling capacity through the introduction of low molar mass tensoactives in the presence of different electrolytes; and 3) the separation of phases caused by the mixture with tensoactives and the determination of the microstructure. In parallel, chemical modifications were carried out on carrageenan molecules with the aim of obtaining fractions with some amphiphilic character. The carrageenans, modified or not, were characterized in relation to the type and proportion of contra-ions, size exclusion chromatography, RMN, FTIR and finally HPLC. The results obtained in this project, in addition to their fundamental scientific aspect, may contribute to the broadening of the application of carrageenans in different formulations, such as the cosmetic and pharmaceutical areas. (AU)