Antagonistic effects of amylopectin and amylose molecules on the starch inter- and intramolecular interactions during retrogradation

Abstract Starch retrogradation property is critical for developing functional foods with desirable nutritional and textural attributes, while its nature currently remains elusive. The current study investigated the relations between starch chain-length distributions (CLDs) and interaction patterns (i.e. intermolecular versus intramolecular interactions) of starch molecules during the retrogradation process. CLDs for different waxy potato and sago starch mixtures were characterized by size-exclusion chromatography, and molecular interactions were characterized by differential scanning calorimetry and small amplitude oscillatory shear rheological test. Results for the first time showed that amylose molecules were involved in the formation of short-range intermolecular interactions with amylopectin molecules. Most intermolecularly heterogenous double helices were formed at the 1 : 1 mixing ratio of waxy potato to sago starch. Although the addition of waxy potato starch to sago starch increased the overall amount of short-range double helices, the amount of short-range intermolecular double helices was decreased. It suggests that there was an antagonistic effect between the formation of short-range inter- and intramolecular double helices. These results help a better understanding of the interaction patterns of amylose and amylopectin molecules during the retrogradation process.