Ground Nut Oil (Arachis Oil) : Preparation, Chemical Constituents and Uses

Morphology and Distribution of Ground nut Plants:

Ground nut oil is a fixed oil expressed from the seed kernels of cultivated varieties of Arachis hypogaea of the family Leguminosae. It is also called as Peanut oil. Arachis plant is grown in Brazil. It is extensively cultivated in Southern United States, China, Africa and India.

Peanut leaves and freshly dug pods

Preparation of Ground nut Oil:

Peanut kernels contain fixed oil and the graded, cleaned kernels are crushed to get the oil by expression. Further quantity of oil is collected by hot expression method. After mixing them together, it is allowed to stand for sometime for separating stearin and filtered. The oil is then treated with fueller’s earth or carbon for bleaching and filtered thoroughly by filter presses.

Peanut cake or peanut oil meal is rich source of proteins which are crude proteins. These crude proteins are used as cattle feed or as raw material for the preparation of protein isolate.

Chemical Constituents of Groundnut Oil:

Arachis oil contains glycerides of fatty acids like oleic, linoleic, stearic and arachidic acid. Other acids like lignoceric and palmitic acids are also present. Raw oil contains aflatoxin and colouring substances. By refining the oil the colour, impurities and aflatoxin are removed. Aflatoxin is a carcinogenic substance produced by the fungal growth.

Uses of Groundnut Oil:

• Arachis oil is used as a solvent for intramuscular injections.
• Arachis oil is used in the preparation of liniments, plasters and soap.
• Arachis oil is used as a lubricant.
• Arachis oil produces a firm and white soap.
• Arachis oil is principally an edible oil.

Peanut oil is adulterated with cotton seed oil or sesame oil.