Although it is touted as one of the healthiest oils in the world, rice bran oil is not reaching its full production potential.
With that in mind, the major rice bran oil producers – India, Japan, China, Thailand and Vietnam – formed the International Association of Rice Bran Oil (IARBO) in 2013. The group has hosted two conferences focused on rice bran oil, the most recent of which was August 2015 in Mumbai, India. The event attracted 400 delegates and special invitees from around world, as well as exhibitors who showcased their products and the latest technologies in rice bran oil.
“This conference will give all our delegates the opportunity to listen to fellow delegates from other countries, and to have discussions with them, which will surely help in achieving the objectives of the IARBO,” said A. R. Sharma, IARBO president, in his opening remarks at the second conference.
IARBO has multiple objectives including: encouraging innovations in rice brain oil processing; standardizing specifications of rice bran oil; promoting international trade by improving communication among producers; and creating awareness of the health benefits of the oil.
Rice bran oil specifics
Rice bran oil is the oil extracted from rice bran, which is the oily layer between the paddy husk and the white rice that contains 15%-22% of oil. The oil is considered one of the healthiest in the world with vitamins, antioxidants, nutrients and no trans fats. It can be used to fry, saute, in salad dressing, baking – anywhere that cooking oil is used.
Because of the complex refinement process, rice bran oil is more expensive than soybean or rapeseed oils, but it is considered a premium oil like sesame or olive oils.
Worldwide, actual rice bran oil production is far below its potential. Of the 476 million tonnes of rice produced in 2014-15, there was a rice bran potential of 23.8 million tonnes (5% of rice production), according to B.V. Mehta, executive director, The Solvent Extractors’ Association of India.
With 17.5% recovery, the potential rice bran oil production for that year was 3.6 million tonnes. Only 1.5 million tonnes was produced, leaving a world untapped potential of 2.1 million tonnes, Mehta said. The leading producers include India at 950,000 tonnes, followed by China at 200,000 tonnes, Japan at 80,000 tonnes and Thailand at 50,000 tonnes. The remaining 220,000 tonnes came from other countries.
Rice bran oil has numerous advantages in cooking and to the health of consumers. It works well as a salad oil and is more stable under frying conditions than any other vegetable oil due to a balance between linoleic and oleic acid, a very low linolenic and high level of antioxidants. Rice bran oil also has a very good shelf life compared to other cooking oils because of these antioxidants.
Studies have shown that rice bran oil in the diet significantly reduces LDL cholesterol and triglycerides, increases HDL cholesterol (good cholesterol), inhibits platelet aggregation and prevents cardiovascular diseases. Clinical studies from Japan, India and the U.S. have confirmed these results and named rice bran oil as a “health oil,” according to IARBO.
With every 1% reduction in cholesterol, there was a 2% decrease in the risk of coronary heart disease. Thus, rice bran oil in the diet significantly reduces cholesterol without any side effects known to exist with pharmaceutical drugs and is the healthiest of all oils for human consumption.
The rice bran oil unsaponifiable fraction is rich in vitamin E complex, tocopherols and tocotrienols, a unique antioxidant known as gamma oryzanol, high quantities of phytosterols, polyphenols and squalene.
Oryzanol has been reported to have various hormone-like effects on the autonomic nervous system. It has been shown to have growth promoting activity, to maintain estrous cycle and to increase capillary development in skin. Oryzanol amounts to 2% of crude rice bran oil and 1.7% of degummed oil. These compounds are concentrated in the gum and soap stock from refining.
In a study at the Kobe University School of Medicine in Japan, where oryzanol was given to a person, there was a significant lowering of total serum cholesterol. The study was consistent with the hypothesis that hypo-cholesterol activity in rice bran resides mainly in the unsaponifiable fraction of the lipid. Various other therapeutic benefits have been attributed to rice bran oil and to oryzanol.
Phospholipids are also produced from the gums removed from crude rice bran oil, IARBO said. These are diacyl glycerol-phosphate compound which are 4%-5% of the rice bran lipid. Phosphatidyl choline (lecithin) has been shown to decrease cholesterol absorption in humans and is efficient in increasing blood choline.
Wax comprises 3%-4% of crude rice bran oil that has been extracted at a high temperature. Rice bran wax is composed of esters of long-chain fatty acids (C16-C26) and fatty alcohols (C22-C30). It can be isolated by crystallizing and settling at low temperature and purified by washing with acetone or ethanol to remove the residual oil, IARBO said. Rice bran wax is approved in the U.S. as a releasing agent for plastic packaging material intended for food contact and is used as a coating for fresh food and vegetables to prevent moisture loss. It also is used as a base for lipstick and other cosmetics.
Production of rice bran oil is a complicated process with its own set of difficulties. Its high content of waxes, free fatty acids, unsaponifiable constituents, phospholipids, glyco-lipids and its dark color make the refining process difficult.
After rice bran pre-treatment, the process involves extracting, filtering, steaming, stripping and finally crude oil extraction. The fines content in the rice bran is large, and the starch content is high.
With the continuous moisture and heat used in the process, starches absorb the water and swell. This generates the gluing effect, which can block the spraying access line and immersion of mixed oil in the extracting screen. It will also make it difficult to discharge.
Once the starch in the wet rice bran dredge is pasting, desolventizing will be difficult. With improper processing, the acid value in the crude bran oil ascends quickly, which means the oil is likely to oxidize and increase the depth of color.
After extraction, the product has to be refined in a process that includes degumming, drying, discoloring, filtering, de-acidifying, deodorizing, dewaxing and degreasing.
During refining, the high free fatty acid content can reduce the yield. The wax makes the liquid milky, which also reduces the yield, and it can easily attach to the starching clay. This means more starching clay is needed for effective discoloring. Wax content beyond a certain limit will make the oil unsuitable for frying.
If the rice bran powder content is too high, it will generate entrainment, which reduces the refining yield. The powder will precipitate in the oil tank, which means frequent equipment cleaning is necessary. Powder can cause damage of transmission equipment such as the water pump, mixing machine and centrifuge.
India, the leading rice bran oil producer, is a good example of how to improve consumer acceptance and awareness of the oil. Although the nation has produced rice bran oil for decades, it has not received much attention until the last few years, said Angshu Mallick, chief operating officer, Adani Wilmar Ltd., at the August conference.
With the launch of Fortune Rice Bran Health in 2012, the first brand to promote 100% rice bran oil, and subsequent promotions by other brands, rice bran oil has been in the limelight.
Rice bran oil sales in India increased by 59% in 2013-14, more than other type of oil.
Several factors led to the oils success in India, Mallick said, including the fact that it can easily be produced in India.
The population is also becoming more health conscious, and disposable incomes are increasing, meaning people are willing to pay a premium for healthy products. Although there are other healthy oils, there are few options and the prices are typically higher, Mallick said.
Still, rice bran oil faces some challenges, including its newness to consumers, and the fact they are resistant to change. It also has perceptual barriers about the color and taste of the oil. Dark colored refined oils are considered impure and not good for consumption. Consumers are skeptical about health claims, and don’t believe changing their oil will make a huge difference.