Effect of interactions between starch and chitosan on waxy maize starch physicochemical and digestion properties

Physicochemical and digestion properties of chitosan modified starch prepared by dry heat treatment were investigated. Starch granule aggregation occurred following the addition of chitosan and this trend was enhanced with increasing chitosan concentration. The size of chitosan modified starch particles was about six times of that of the native starch granules. Interactions between the hydroxyl groups of starch and the amino groups of chitosan was confirmed by Fourier transform infrared spectroscopy analysis. The disappearance of the trough in the Rapid Visco Analyzer profile indicated that the cross-links increased the starch shear resistance. The cross-links between starch and chitosan also reduced starch digestion rate compared to the control (p < 0.001), and this reduction was further enhanced with an increasing chitosan concentration. Additionally, the addition of chitosan altered starch digestion kinetics from one phase to two phases, implying that chitosan modification changed both starch structure and its digestion behaviors.