Uses
Annually, 270,000–360,000 tonnes (600–800 million pounds) of castor oil are produced for a variety of uses. Food and preservative
In the food industry, food-grade castor oil is used in food additives, flavorings, candy (e.g., polyglycerol polyricinoleate 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. Traditional medicine
Use of castor oil as a laxative is attested to in the circa 1550 BCE Ebers Papyrus, and was in use several centuries earlier.Although used in traditional medicine to induce labor in pregnant women, there is no clinical evidence that castor oil is effective for dilating the cervix or inducing labor.According to the American Cancer Society, "available scientific evidence does not support claims that castor oil on the skin cures cancer or any other disease." Skin and hair care
Castor oil has been used in cosmetic products included in creams and as a moisturizer. Small amounts of castor oil are frequently used in cold-process soap to increase lathering in the finished bar. It also has been used to enhance hair conditioning in other products and for supposed anti-dandruff properties. Coatings
Castor oil is used as a biobased polyol in the polyurethane industry.
Castor oil is a vegetable oil pressed from castor beans. It is a colourless or pale yellow liquid with a distinct taste and odor. Its boiling point is 313 °C (595 °F) and its density is 0.961 g/cm3. It includes a mixture of triglycerides in which about 90% of fatty acids are ricinoleates. Oleic acid and linoleic acid 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, and perfumes. Etymology
The name probably comes from a confusion between the Ricinus plant that produces it and another plant, the Vitex agnus-castus. An alternative etymology, though, suggests that it was used as a replacement for castoreum. Composition
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 atom. 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/kg ($0.41/lb), whereas U.S. soybean, sunflower, and canola oils sold for about $0.30/kg ($0.14/lb).