Preparing Xanthan-Chitosan Composites in Glycerol

Anionic xanthan (X) and cationic chitosan (C) form xanthan-chitosan (X+C) complexes by electrostatic attraction in an aquatic environment where concentration of either of the polysaccharides does not exceed 2.5 wt %. Covalently bonded xanthan-chitosan (X−C) composites were prepared in dry glycerol with concentration of either of the polysaccharides in the range 0.025 to 50% weight. In dry glycerol xanthan and chitosan formed covalent bonds via condensation reactions. Carboxyl groups donate OH⁻ while amino groups donate H⁺ to make H₂O; water is also condensed in Maillard reactions during crosslinking of both xanthan and chitosan with glycerol. X−C composites were made at xanthan to chitosan ratio in range 0.08 to 26. Porosity of X−C composites decreased with increasing xanthan content and decreasing chitosan content. X−C composites prepared at various xanthan to chitosan ratio showed different H₂O absorption, hardness, release and absorption of chemicals, and they differed in other characteristics as well. These results are significant for scientific community, food, material, pharmaceutical, and other fields.