Abstract:
Rice is the staple food in Sri Lanka, significantly contributing to the nutritional status
and dietary intake of the population. This study compared the nutritional and
functional properties of cooked rice from raw and parboiled forms of three new
improved rice varieties available in Sri Lanka: Bg 375, Bw 372, and Ld 376.
Parboiling was performed using a domestic rice cooker, followed by sun drying to
14% moisture content. Both raw and parboiled rice samples were dehusked, polished,
cooked with adequate water (rice: water ratio for raw rice - 1:3, parboiled rice - 1:4)
for 40 – 50 minutes, air-dried, and then oven-dried until a constant weight was
achieved. The dried grains were ground, sieved, packed, and stored in a refrigerator
for analysis. Results showed that parboiled Bg 375 had the highest moisture content
(wet basis, w/w%) at 77.63±0.71 (p<0.05), while raw Bw372 exhibited the highest
ash content (dry basis, w/w%) at 1.35±0.17 (p<0.05) and fat content (2.00±0.08, dry
basis, w/w%). Among all samples, dietary fiber content was highest (p<0.05) in
parboiled Bg 372 (14.21±0.71) and parboiled Bg 375 (13.29±0.39). Parboiled Bg 375
had the highest resistant starch content (dry basis, g 100g-1) at 5.41±0.00 (p<0.05),
while parboiled Bw 372 and Ld 376 recorded the highest total phenolic content (TPC)
(43.38±0.92 mg GAE g-1 CW basis) and oxygen radical absorbance capacity
(586.59±0.003 mmol TE mg-1), respectively. Prebiotic activity assay scores ranged
from 0.21±0.01 to 1.48±0.06. Overall, raw rice samples exhibited significantly higher
(p<0.05) moisture (74.67±1.99, wet basis, w/w%) and fat content (1.49±0.52, dry
basis, w/w%) compared to parboiled samples. In contrast, parboiled rice displayed
enhanced levels of dietary fiber (12.86±1.45, dry basis, w/w%), resistant starch
(4.55±0.87, dry basis, g 100g-1), ash (1.03±0.15, dry basis, w/w%), and TPC
(37.00±4.87 mg GAE g-1 CW basis), suggesting that parboiling improves the
functional properties of rice, potentially offering greater health benefits compared to
raw rice.
