Abstract:
Resistant starch (RS) is considered to possess several health benefits. The
content of RS in different varieties of rice in the Northern Province of Sri Lanka
and the effect of different traditional methods of processing on RS content were
determined. Five commonly consumed rice varieties [two improved (Bg 250 and
Bw 351) and three traditional varieties (Periyavellai, Pachchaperumaal and
Moddakaruppan)] were selected. Samples were processed by roasting, cooking
with and without draining of excess water and cooking the presoaked rice
without draining the excess water. The total starch, non-RS and RS contents
before and after processing were estimated. The highest and lowest amounts of
RS were found in raw Pachchaperumaal (27.87±0.32%) and Bw 351
(18.94±0.26%) varieties, respectively. When roasted, highest and lowest
amounts of RS were found in Bw 351 (11.09±1.29%) and Bg 250 (7.32±1.68%),
respectively. Further, Bw 351 contained highest amount of RS when cooked
without draining the excess water (11.63±1.2%) and with draining excess water
(11.40±0.50%). Periyavellai contained lowest amount of RS when cooked
without draining the excess water (7.04±0.5%) and with draining excess water
(4.45 ±0.60%). Periyavellai contained the highest amount of RS (14.50±0.84%)
and Moddakaruppan contained the lowest amount of RS (11.75±0.58%) when
the rice was pre-soaked before cooking and without draining the excess water.
On the basis of complete randomized design, cooking methods have effect on RS
content (p<0.05). The RS contents of raw rice and pre-soaked rice cooked
without draining of excess water were significantly different. Different
processing methods have significantly reduced the total starch, non-RS and RS
contents. As the processed rice is consumed; among the rice varieties and the
processing methods, consuming presoaked Periyavellai rice variety cooked
without draining excess water could be recommended to have more RS.
