Thermal properties were measured using an X-DSC7000 DSC
analyzer (Japan). Each sample (3.5 mg) was weighed, put in an
aluminum capsule and added with 7.0 mL of distilled water. Then
the capsules were sealed and equilibrated overnight at 4 C. Gelatinization
was characterized by measurement from 20 to 90 C at a
rate of 5 C/min. After that, the capsules were stored at 4 C for 7
days, followed by characterization of retrogradation with the same
method as gelatinization. The onset temperature (To), peak temperature
(Tp), conclusion temperature (Tc), enthalpies in gelatinization
(DH1) and retrogradation (DH2) were determined. The
degree of retrogradation was calculated as the ratio of DH2 to DH1.
2