Ricebran wax

Description

Both bran and bran coats obtained in the milling of rice, Oryza sativa L., family Gramineae, contain a lipid wax. Rice bran contains 15 to 18% and rice polishings 20% of oil. The commercial yield (of edible rice oil) is, however, more like 5 to 7%, varying with the temperature at which the extraction is made, the solvent used, source and history of the bran, and other factors. The yield of wax, if recovered from the crude rice oil, is somewhat less than 2%, or less tan 0.4% on the bran basis.

Oil from rice bran has now become an edible oil of commercial value; hence ricebran wax may become of importance as a by-product. Solvent extracted from the freshly milled rice bran, the oil is low in free fatty acid. It can be converted by conventional refining and bleaching procedures into a clear, light-colored product having a good flavor. The bran from which the oil has been extracted is bagged and sold as an animal feed.

The crude wax containing glycerides may be separated from crude rice oil by wintering at 20-25ºC, and then treated with a solvent such as 5% methanol in commercial n-hexane, to effect a sharp separation of soluble and insoluble parts. Without the use of solvent the wax from the tank settlings cannot be effectively separated by filtration methods.