A comparative study on starch digestibility, glycemic index and resistant starch of pigmented (‘Njavara’ and ‘Jyothi’) and a non-pigmented (‘IR 64’) rice varieties

In vitro starch digestibility and glycemic indices
of three rice varieties- ‘Njavara’, ‘Jyothi’ (pigmented rice
verities) and ‘IR 64’ (non-pigmented rice) with similar
amylose content were studied. Starch digestibility studies
showed differences in glycemic response in three types of
rice. The rate of starch hydrolysis was maximum (67.3%) in
‘Njavara’ rice compared to other two rice varieties.
‘Njavara’ exhibited the lowest kinetic constant (k) indicating
inherent resistance to enzymatic hydrolysis. The glycemic
load (GL) and glycemic index (GI) of ‘Njavara’ were similar
to ‘Jyothi’ and ‘IR 64’. Resistant starch content was high in
pigmented rice varieties compared to ‘IR 64’. The resistant
starch content of dehusked and cooked rice increased with
the storage time at refrigeration temperature (4°C). ‘Njavara’
is an easily digestible rice and can be used for baby and
geriatric foods.