Use of Low Temperature for the Production of Superior Quality Rice Bran Oil.

Routine processing of crude oil in rice bran oil
industries results in heavy loss of oil, natural nutrients
and antioxidants. Hence, there is a need for a simple
method involving minimal processing to obtain a good
quality and natural nutraceuticals retained rice bran
oil. The studies on rice bran extraction carried out
with two extraction solvents and three extraction
temperatures indicated that the rice bran oil obtained
by soxhlet extraction at low temperature (5°C) by
using hexane provided the best results. This haziness
free crude oil having color (57.0 Lovibond units in 1"
cell), unsaponifiable lipids (4.4 g / 100g oil), wax (1.0
g / 100g oil), phospholipids (1.0 g / 100g oil), oryzanol
(1.8 g / 100g oil) and tocopherols (100 mg / 100g oil)
showed significant reduction (p ≤ 0.05) as against
color (18.6%), wax (54.5%), phospholipids (68.8%),
and unsaponifiable lipids (22.8%) of the crude rice
bran oil obtained by conventional soxhlet extraction
process at normal extraction temperature (35-40°C).
The low temperature extracted oil retained the inherent
nutraceuticals like oryzanol (1.8 g / 100 g oil) and
tocopherols (100 mg / 100 g oil) to a greater extent
as compared to commercially available physical (1.3
g / 100 g oil & 70 mg / 100 g oil) and chemical refined
(0.3 g / 100 g oil & 57 mg / 100 g oil) rice bran oils.
The low temperature extracted oil was also found to
have better oxidative stability (38.7-48.7% less
peroxide formation) and radical scavenging activity
(92%) as compared to commercially available physical
(87%) and chemical refined (75%) rice bran oils
respectively.