Castor oil

Castor oil is a vegetable oil pressed from castor beans. The name probably comes from its use as a replacement for castoreum. Castor oil is a vegetable oil pressed from castor beans. The name probably comes from its use as a replacement for castoreum. Castor oil is a colourless to very pale yellow liquid with a distinct taste and odor. Its boiling point is 313 °C (595 °F) and its density is 961 kg/m3. It is a triglyceride in which approximately 90 percent of fatty acid chains are ricinoleates. Oleate and linoleates are the other significant components. Castor oil and its derivatives are used in the manufacturing of soaps, lubricants, hydraulic and brake fluids, paints, dyes, coatings, inks, cold resistant plastics, waxes and polishes, nylon, pharmaceuticals and perfumes. Castor oil is well known as a source of ricinoleic acid, a monounsaturated, 18-carbon fatty acid. Among fatty acids, ricinoleic acid is unusual in that it has a hydroxyl functional group on the 12th carbon. This functional group causes ricinoleic acid (and castor oil) to be more polar than most fats. The chemical reactivity of the alcohol group also allows chemical derivatization that is not possible with most other seed oils. Because of its ricinoleic acid content, castor oil is a valuable chemical in feedstocks, commanding a higher price than other seed oils. As an example, in July 2007, Indian castor oil sold for about US$0.90 per kilogram (US$0.41 per pound) whereas U.S. soybean, sunflower and canola oils sold for about US$0.30 per kilogram (US$0.14 per pound). Annually 270,000–360,000 tonnes (600–800 million pounds) of castor oil are produced for a variety of uses. In the food industry, castor oil (food grade) is used in food additives, flavorings, candy (e.g., polyglycerol polyricinoleate or PGPR in chocolate), as a mold inhibitor, and in packaging. Polyoxyethylated castor oil (e.g., Kolliphor EL) is also used in the food industries. In India, Pakistan and Nepal food grains are preserved by the application of castor oil. It stops rice, wheat, and pulses from rotting. For example, the legume pigeon pea is commonly available coated in oil for extended storage. Use of castor oil as a laxative is attested to in the circa 1550 BC Ebers Papyrus, and was in use for several centuries prior. The United States Food and Drug Administration (FDA) has categorized castor oil as 'generally recognized as safe and effective' (GRASE) for over-the-counter use as a laxative with its major site of action the small intestine where it is digested into ricinoleic acid. Despite castor oil being widely used to induce labor in pregnant women, to date there is not enough research to show whether it is effective to dilate the cervix or induce labor.