Characterization of Corn Starch‐Calcium Alginate Xerogels by Microscopy, Thermal, XRD, and FTIR Analyses

Abstract

AbstractAlginate‐based hydrogels supplemented with corn starch (0%, 25%, 50%, and 75% relative to total solids) are obtained as a preliminary step to fabricate the corresponding xerogels. Microscopy showed that starch incorporated porosity to xerogels, while alginate tended to form layered structures. X‐ray analysis showed that the relative crystallinity is small (non‐higher than 5%), indicating the xerogels are basically amorphous structures. Thermal analysis revealed that starch induced reductions of the disintegration enthalpy, which might be ascribed to a disordered entanglement between starch chains and alginate molecules. FTIR analysis is used to characterize the structure (i.e., bonding) of water molecules in the xerogel structure. Starch increases the formation of clusters of strongly bonded water molecules. Overall, the results show that the addition of gelatinized corn starch result in the formation of a more stable crosslinked alginate structure mediate by the stronger interaction between the water molecules and alginate chains.