Rice bran oil
|Omega-3 fatty acids||α-Linolenic: 2.2%|
|Omega-6 fatty acids||Linoleic: 34.4%|
|Food energy per 100 g (3.5 oz)||3,700 kJ (880 kcal)|
|Smoke point||232 °C (450 °F)|
Rice bran oil is the oil extracted from the hard outer brown layer of rice after chaff ( rice husk). It is notable for its high smoke point of 232 °C (450 °F) and its mild flavor, making it suitable for high-temperature cooking methods such as stir frying and deep frying. It is popular as a cooking oil in several Asian countries, including Japan, India and China.
Rice bran wax, obtained from rice bran oil, is used as a substitute for carnauba wax in cosmetics, confectionery, shoe creams and polishing compounds. It is an edible oil which is used in the preparation of vegetable ghee.
|C14:0 Myristic acid||0.6%|
|C16:0 Palmitic acid||21.5%|
|C18:0 Stearic acid||2.9%|
|C18:1 Oleic acid (an Omega 9 fatty acid)||38.4%|
|C18:2 Linoleic acid (LA, an Omega 6 fatty acid)||34.4%|
|C18:3 α-Linolenic acid (ALA, an Omega 3 fatty acid)||2.2%|
|character||Crude Rice bran oil||Refined oil|
|Density (15-15 °C)||0.913-0.920||0.913-0.920|
|Free fatty acids||5-15%||0.15-0.2%|
A component of rice bran oil is the antioxidant γ-oryzanol, at around 2% of crude oil content. Thought to be a single compound when initially isolated, it is now known to be a mixture of steryl and other triterpenyl esters of ferulic acids. Also significant is the relatively high fractions of tocopherols and tocotrienols, together as vitamin E. Rice bran oil is also rich in other phytosterols.
Literature review shows rice bran oil and its active constituents improve blood cholesterol by reducing total plasma cholesterol and triglycerides, and increasing the proportion of HDL cholesterol. Results of an animal study indicated a 42% decrease in total cholesterol with a 62% drop in LDL cholesterol, when researchers supplemented test subjects' diets with fractionated vitamin E obtained from rice bran oil.
One small-scale study of γ-oryzanol, a mixture of chemicals found in rice bran oil, found that 90% of the women had some form of relief from hot flashes after taking a supplement of the purified concentrate for four to six weeks.
The oryzanol content of the pan heated rice bran oil samples remains approximately the same even when heated at 180˚C for 8 hours, while a decrease in oryzanol content was reported in the case of microwave heating at the same conditions.
One MAJOR problem with this oil is its ratio of omega 6 to omega 3. Rice bran oil contains high amounts of omega-6 fatty acids (linoleic acid) -- and virtually no omega-3 (linolenic acid). This fact alone is enough to strike this oil out of your diet permanently unless you are supplementing with omega-3. The ideal ratio between these two fatty acids is 1:1 and the nutritional habits of most people in developed nations has this ratio soaring more than 15:1 (Omega 6: Omega 3). So unless you are consuming reasonable amounts of Omega 3 in your diet, you might consider to stay away from this oil.
Although rice bran oil has been tested to reduce cholesterol levels, it is important to recognize its high omega-6 content, which can be detrimental to health if used excessively. A high consumption of omega-6 polyunsaturated fatty acids, which are also found in most types of vegetable oils, may increase the likelihood of both breast cancer and prostate cancer. Other analyses suggested an inverse association between total polyunsaturated fatty acids and breast cancer risk.
Omega-3 and omega-6 compete for the same metabolic enzymes. The dietary imbalance that exists in rice bran oil can create all sorts of problems to body processes, including a tendency towards inflammation. This imbalance has been implicated in higher rates of diabetes, cancer, heart disease, stroke, arthritis and skin disorders. It is essentially prone to the same negative health effects as sunflower, safflower, canola and corn oils.
Rice bran oil may also have the potential to be genetically modified in the future, so it's important to ensure only organic sources of this oil are used. Rice bran itself is also potentially high in arsenic so this is another level of concern which requires more research.
Also, the majority of rice bran oil on the market is NOT cold pressed and some may be chemically extracted using solvents, in particular petroleum-derived hexane and high heat.
Rice bran might help lower cholesterol because the oil it contains has substances that might decrease cholesterol absorption and increase cholesterol elimination. One of the substances in rice bran might decrease calcium absorption; this might help reduce the formation of certain types of kidney stones.
- Orthoefer, F. T. (2005). "Chapter 10: Rice Bran Oil". In Shahidi, F. Bailey's Industrial Oil and Fat Products 2 (6 ed.). John Wiley & Sons, Inc. p. 465. ISBN 978-0-471-38552-3. Retrieved 2012-03-01.
- SEA HandBook-2009,By The Solvent Extractors'Association of India
- A.F. Cicero, A. Gaddi (2001). "Rice bran oil and gamma-oryzanol in the treatment of hyperlipoproteinaemias and other conditions". Phytother Res 15 (4): 277–286. doi:10.1002/ptr.907. PMID 11406848. Retrieved 2006-10-09.
- Minhajuddin M, Beg ZH, Iqbal J. "Hypolipidemic and antioxidant properties of tocotrienol rich fraction isolated from rice bran oil in experimentally induced hyperlipidemic rats." Food and Chemical Toxicology. 2005; 43(5):747-53.
- Ishihara, M; Ito, Y; Nakakita, T; Maehama, T; Hieda, S; Yamamoto, K; Ueno, N (1982). "gamma-oryzanol on climacteric disturbance". Nihon Sanka Fujinka Gakkai zasshi 34 (2): 243–51. PMID 7061906.
- Paul, A.; Masih, D., Masih, J., Malik, P. (2012). "COMPARATIVE ANALYSIS OF HEAT DEGRADATION OF ORYZANOL IN RICE BRAN OIL, MUSTARD OIL AND SUNFLOWER OIL BY MICROWAVE AND PAN HEATING". International Journal of Food and Nutritional Sciences 1 (1): 110–117. Retrieved December 2012.