Factors affecting refining losses in rice (Oryza sativa L.) bran oil.

Components of rice bran oil have been assessed for
their effect on refining losses. Rice bran oil used in the
study had the following (percent) analysis: free fatty
acids, 6.8; phosphatides, 1.25; wax, 2.85; monoglycerides,
1.67; diglycerides, 4.84, and oryzanol, 1.85; the rest
(80.74) was mostly triglycerides. The phosphatides and
mono- and diglycerides had no noticeable effect on
refining losses at levels of up to 2% in the oil. Waxes
and oryzanol increased the refining losses substantially.
In model experiments where these were incorporated
into peanut oil individually and in combination,
the wax at as low a level as 1% increased the refining
losses by about 80% more than control and the refining
losses increased with concentration of wax. Oryzanol
had a similar effect. When wax and oryzanol were
present together in the oil, the effect was synergistic—
the refining losses were higher than the sum of their
individual effects. Phosphatides, mono- and diglycerides
tended to reduce the adverse effect of wax and oryzanol.
The main components responsible for higher than normal
refining losses in rice bran oil have been identified
as wax and oryzanol.