Abstract:
The effects of gelatinization on slowly digestible (SDS) and resistant starch (RS) of native and
modified canna starches were investigated. Starch slurries (5% and 10% w/w) were gelatinized at
100 C for 5, 10, 20 and 40 min by using rapid visco analyzer (RVA). The results showed that the
degree of gelatinization (DG) values of all starch samples increased with increase of gelatinization time.
The DG values of 10% (w/w) starches were higher than those of 5% (w/w) starch samples. The RS
contents in all gelatinized starches decreased with increase of gelatinization time and the RS contents of
10% (w/w) starch samples were lower than those of 5% starch samples. Chemical modification affected
the DG value as well as the RS/SDS contents. The RS contents in 10% (w/w) acetylated,
hydroxypropylated and octenylsuccinated canna starches gelatinized at 100?C for 40 min were 27%,
32% and 45%, respectively, which were higher than that of the native starch (16%). Canna starch
modified by crosslinking with phosphate ester had the highest SDS contents when gelatinized for 20-40
min. Modification of canna starch by heat moisture treatment (HMT) resulted in a lower content of RS
for all treated samples. However, the HMT25 gelatinized for 5-10 min contained a higher amount of
SDS, compared to the unmodified starch.