This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
The oil expressed from the seeds of Arachis hypogoea Linne (N.O. Leguminosoe). The plant is an annual, attaining 1 m. in height; the lower flowers develop fruits which bury themselves in the earth and there ripen; a single plant may produce as many as 100 fruits. These contain usually from one to three reddish brown seeds the chief constituents of which are fixed oil (about 45 per cent.), starch and proteids (about 27 per cent.). The seeds are imported chiefly from West and East Africa and from India. The press-cake forms a valuable cattle food.
The fixed oil is pale yellow or greenish yellow with a nutty odour and taste. Specific gravity 0.916 to 0.921; iodine value 83 to 110; consists chiefly of the glycerides of arachic, stearic, lignoceric, oleic, hypogaeic and linolic acids. It may be identified by saponifying 1 c.c. with 15 c.c. of N/1 alcoholic solution of potash, allowing the mixture to stand for 24 hours at 15.5°, heating on a water-bath for 3 minutes and again setting aside, when crystals of (impure) potassium arachate separate.