Effects of amylose and phosphate monoester on aggregation structures of heat-moisture treated potato starches.

For three cultivars of potato starch, heat-moisture treatment (HMT) displayed an influence on the aggregation structures at different scale levels. With HMT, the granular morphology of potato starch granules remained similarly, and an increase in the average repeat distance of semi-crystalline lamellae was observed. The crystalline structure and birefringence were also affected. Moreover, the polymorphic transformation (B → A+B) could be related to dehydration, whereas the decrease in the degree of crystallinity might be resulted from the rupture of hydrogen bonds. Interestingly, amylose could act as the backbone of the aggregation structures of potato starch to provide resistance to HMT, but phosphate monoester could promote the destruction during HMT. In addition, compared with amylose, phosphate monoester played a more significant role in changing the average repeat distance of semi-crystalline lamellae (long period) during HMT.