Supramolecular and molecular structures of potato starches and their digestion features.

This work inspects the supramolecular/molecular structures and digestion rate of potato starches (BEM, C7H, CP2 and CP4) as affected by starch biosynthetic enzymes. Among the starches, CP2 had a lower digestion rate with a higher paste heating stability. Regarding this, predominantly enzyme-sets (i) and (ii) were revealed to produce amylopectin chains. For CP2, the reduced activity ratio of starch-branching enzymes to soluble starch synthases allowed more long amylopectin chains (polymerization degree ≥ 34). Such molecular features tended to increase the crystallites and thicken the lamellae. With similar surface morphology and amylose content, the bulk density of chain packing in CP2 supramolecular structures could be increased. Then, there were an increase in the resistance of starch structures to hydrothermal effects, and a reduction in the enzyme hydrolysis rate. Also, the increased long amylopectin chains played roles in increasing the paste stability during heating with shearing and in reducing the digestion rate.