Structural and physicochemical property changes during pyroconversion of native maize starch

Pyrodextrins are widely applied in industry as adhesives, coatings, binders, and in food as dietary fiber. In this study, the dynamic changes of structure and physicochemical property during pyroconversion of native maize starch are investigated. By quantifying the variations of chain-length distribution (CLD) between native starch and pyrodextrins, it is found that 1) the long starch chains with degree of polymerization (DP) about 500–20000 are degraded while its content is not significantly varied between pyrodextrins; 2) the content of intermediate-long chains with DP 20–500 increases with temperature, indicating more pyrodextrin molecules with the equivalent Rh∼1.5–9.4 nm are newly formed; 3) the content of A and B1 chains are not largely varied between pyrodextrins with temperature ≤190 °C, suggesting that the repolymerization might be more likely occur in the amorphous lamellae. This study improves the understanding of structural and physicochemical property changes during the pyroconversion process of native maize starch.