Striking Oil With Fat

Researchers have found a new way to convert oils into solids, a process that could be useful in a wide range of processes from cleaning up oil spills to making healthier food.

Most methods of converting oils into solids rely on a chemical reaction called hydrogenation, which adds hydrogen atoms. When used to make food products such as butter and cheese substitutes, hydrogenation is expensive. It also creates high levels of unhealthy saturated fatty acids. Now, biochemist Ram Rajasekharan of the Indian Institute of Science in Bangalore and his student Jayanth Daniel have discovered a way to solidify oil at room temperature without any change in chemistry, a process called organogelation.

The researchers initially focused on the Indian berry (Garcinia indica), which accumulates a fat so hard it's earned the nickname "concrete oil." When they mixed one part fat from the berries with five parts purified sunflower oil, the mixture gelled in 12 hours at room temperature and in just 1 hour at 4ºC. Further experiments showed that any saturated fatty acid that has between 10 and 31 carbon atoms can perform the same trick, although the gelling efficiency was more efficient with smaller molecules. Moreover, saturated wax esters--a certain type of derivative of fatty acids used to make cosmetics--were just as efficient, the duo reports in a paper accepted by the Journal of the American Oil Chemists' Society.

The process, which the researchers have patented, could be a cheaper way to make butter and cheeselike products from vegetable oils, which are considered healthier than animal fats. It could also make it easier to give oil-based cosmetic creams the right consistency, the researchers say. And if an oil tanker breaks, fatty acids could be mixed with the oil to solidify it, preventing it from spreading and making it easier to recover. The method works with several types of crude oil, petrol, diesel, and kerosene, Rajasekharan and Daniel say.

Oil chemist Rakesh Kumar Trivedi of the Harcourt Butler Technological Institute in Kanpur, India, calls the study "excellent" and predicts that the finding, because of its many potential applications, will have "significant economic effect."

Related sites
Healthy and unhealthy fats
Ram Rajasekharan's Web page
Harcourt Butler Technological Institute