Effect of Different Extraction Solvents on the Composition and Quality of Crude Oil Extracted from Rice Bran

The effect of using different extraction solvents on
the content, composition and quality of crude oil
extracted from rice bran was studied. Freshly milled
brans belonging to three paddy cultivars (IR-64, Java,
Bangla) and four commercial bran samples were
procured from two local rice mills and two vegetable oil
manufacturing industries. Four organic solvents
belonging to non polar (hexane, petroleum ether) and
polar (acetone, isopropanol) groups were chosen and
were used for extraction of oil in a Soxhiet extraction
apparatus. The oil (bran basis) and oryzanol (oil basis)
values for different bran samples for non-polar (hexane)
and polar (acetone) solvents were IR-64: 19.1, 21.4,
1.85 and 1.83%; Java: 15.0, 18.8, 3.15 and 3.26%;
Bangla: 19.0, 20.2, 2.0 and 2.12; SKAR bran: 17.1,
19.7, 2.39 and 2.59%; NKA bran:W.6, 18.7, 1.75 and
1.85; and WB bran: 19.0, 19.6, 2.2 and 2.31%;
respectively. The oil content increased by 3.2-25.8%
for the six bran samples studied with increase in
polarity of extraction solvent. Also, the oil samples
obtained from NKA bran (commercial bran) showed
major changes in colour (108-148% increase), wax
(156-440% increase) and phospholipids content (21-
112% increase), and minor changes in appearance
(greenish hazy liquid to greyish green hazy liquid), and
oryzanol content (5.7-8.6% increase) respectively, with
increase in polarity of solvent. It is concluded from the
study that the content, composition and quality of
crude oil so extracted changes with a polar solvent
namely, isopropanol or acetone when used for oil
extraction.