Like the garden pea, the groundnut plant is a member of the family Leguminosae. It is an annual, herbaceous plant growing approximately 30-60 cm high, with hard, angular stalks.
The flowers are brilliant yellow, develop rapidly and bloom for only a few hours. The seeds are packed in twin layers. The seedpods are yellow with a wrinkled surface, each containing 1-4 seeds the size of hazelnuts. The yellow-white nuts are enclosed in thin, red-brown shells that are easily opened when the seeds are dry and ripe.
Some tall varieties must be ridged like other root vegetables. During a period of 2-6 weeks the seeds are air-dried, which lowers their moisture content from 40 to 10%.
The seeds will thus keep longer and are easier to shell. Groundnuts are mainly exported unshelled since the shells prevent transport damage.
Today the most important areas of cultivation are China, India, West and North Africa and the USA. The main export countries for groundnut oil are Argentina, Sudan and Senegal. There are over 22 million tonnes of groundnuts produced with China producing nearly 10 million tonnes. Because there are relatively limited supplies, and a constant high demand, groundnut oil usually commands a considerable price premium over most other cooking or frying oils.
The oil is relatively robust and has a characteristic slightly nutty taste although it is odourless.
Groundnuts contain 40-50% fat and 24-35% proteins. Groundnuts are pressed to derive the oil. The protein-rich press residues are used as animal feed. The composition of Groundnut oil varies depending on the growing area with oil from Senegal having highl levelsl of Monounsaturates.
The typical composition of groundnut (peanut) oil is (%):
Food allergies are caused by the protein components of food. Edible oils and fats in the EU undergo extensive refining processing which removes virtually all protein from the oil. It was always thought unlikely that refined groundnut oil could be allergenic and this has now been scientifically tested. Research has shown that refined groundnut oil would not cause reactions for the overwhelming majority of peanut allergic individuals and if any reaction did occur, it would almost certainly be mild. As predicted, the research did show, however, that unrefined oil could cause a reaction in some people, so should be avoided by those with peanut allergy.
New EU regulations on food labelling require the labelling of certain known allergens. Whilst refined groundnut oil is thought to be safe for peanut allergics, all groundnut oil, refined or unrefined, is now listed on the packaging, if not already included in the product name.