Rice Bran Oil (RBO) is one of the most nutritious and healthful edible oils owing to the presence of an abundance of natural bioactive nutraceuticals such as γ-Oryzanol, tocopherols, tocotrienols, and sterols with a balanced fatty acid composition. It is also known to have a high anti-oxidant stability and smoke point, making it ideal for cooking and frying applications.
Only RBO is rich in γ-Oryzanol, with content ranging from 1% to 2% in crude RBO. In order to retain the same high levels of γ-Oryzanol in the final oil, a special process, known as Physical Refining, is used. γ-Oryzanol is a mixture of ferulic acid esters of triterpene alcohols and phytosterols. The individual components were previously identiﬁed as cycloartanyl ferulate, 24-methylene cycloartanyl ferulate, campesteryl ferulate, β-sitosteryl ferulate, and cycloartenyl ferulate. Some of the beneﬁcial biological effects attributed to γ-Oryzanol are:
- Helping lower the levels of bad cholesterol (LDL) and increase those of good cholesterol (HDL) in the blood. It prevents the biosynthesis of cholesterol by inhibiting the activity on the enzyme HMG-CoA reductase* .
- Improvement of capillary action of blood vessels
- Fighting free radicals, which are the crucial factors that could cause cardio vascular diseases and cancer
- Improving skin tone, alleviating menopausal symptoms, stimulating nerves, and relieving discomfort caused by malfunctioning of nervous system
- Anti-itching, anti-dandruff and anti-aging properties
Tocopherols and tocotrienols (tocols) belong to the Vitamin-E family, which occur naturally in some plants and vegetable, rice bran being one of them. Crude rice bran oil (CRBO) contains relatively high levels of tocols (up to 0.2%), of which about 70% are tocotrienols; this is rare among edible oils.
- These compounds, particularly tocotrienols, prevent lipid peroxidation and play a key role in delaying the pathogenesis of a variety of degenerative diseases such as cardiovascular disease, cancer, inﬂammatory diseases, neurological disorders, cataracts, age-related macular degeneration, and immunomodulation.
RBO also has a balanced Fatty Acid composition. Rice bran oil includes 34% polyunsaturated fats (PUFA), 22% saturated fats (SFA) and 44% monounsaturated fats (MUFA). This composition is extremely close to the American Heart Association (AHA) recommendations for edible oils. It is a rich supply of Essential Fatty Acids (EFAs), Linoleic acid (omega-6 fat), and Linolenic acid (omega-3 fat). They behave as vital internal regulators in the body. It is also free of the harmful trans-fats.
RBO can be termed ‘nutritional oil’, and it is of paramount importance to exploit this unique edible oil to its fullest potential for the health beneﬁts.
Currently, CRBO is chemically and physically refined through phosphoric acid degumming. Chemical reﬁning results in excessive neutral oil loss and the removal of γ-Oryzanol and other bioactive compounds.