Abstract:

This paper describes the results of an exploration into the formation mechanism of slowly digestible corn starch under the condition of annealing treatment. Scanning electron microscope (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were used to study the changes of granule appearance, enthalpy, and crystal structure of corn starch during the annealing treatment (AT). The results showed that AT had no effect on granule appearance and the crystal structure was still type A with a relatively compact connection. Compared with native corn starch, T0, Tp, Tc and ΔT (Tc—T0) of its annealed counterparts with and without the removal of rapidly digestive corn starch in DSC plot exhibited an obvious increase. These investigations suggested that the formation of slowly digestible corn starch was due to more compact structures as a result of the crystal rearrangement, which increased the resistance to amylase.

Key words: annealing treatment, slowly digestible corn starch, formation mechanism, crystal property, granule property