A study of rice bran oil refining

Examination of a number of rice bran oils revealed the presence of monoglycerides (0.5–1.4%) and other hydroxylated compounds such as diglycerides and glucosides. The hydroxyl numbers of the samples ranged from 8.5 to 27, depending on their acidity. On the assumption that the inordinately high refining losses of rice bran oil are due, along with the acidity, to the presence of hydroxylated compounds, the hydroxyl numbers of several samples of that oil were reduced by progressive acetylation with acetic anhydride. This was accompanied by gradual reduction of the refining losses, which seems to support the above mentioned assumption.