Simple thermal and freezing treatments to improve absorption capacity and alter digestibility of canna starch granules*

Swollen canna starches (SCS) were prepared by controlled heating of unmodified and heat-moisture treated (HMT) starch suspensions at sub-gelatinization temperatures; subsequently, freezing was conducted to stabilize the structure of the SCS. Sizes of both unmodified and HMT swollen granules increased with increasing heating temperatures (up to 2.5 times), and freezing resulted in a significant reduction of granular size. The absorption capacities of the swollen starches increased up to 6 times for water and 3 times for tributyrin and palm oil compared to unmodified starch. The differences in absorption capacities of the unmodified and HMT swollen starches were small. Freezing the swollen starches tended to decrease oil and water absorptions, except for unmodified starch swollen at 70 degrees C, where freezing increased water absorption. Freezing significantly decreased the susceptibility of the swollen unmodified starches to amylase digestion and slowed down the digestion of the swollen HMT starches.

Automated summary

Swollen canna starches (SCS) were prepared by heating unmodified and heat-moisture treated (HMT) starch suspensions at sub-gelatinization temperatures, followed by freezing to stabilize the structure. The absorption capacities of swollen starches increased significantly, with a decrease in granular size after freezing. Additionally, freezing decreased the susceptibility to amylase digestion and slowed down the digestion process.