Arachis hypogaea

Groundnut, peanut, earthnut, monkey nut, Manila nut, Chinese nut, pindar, goober pea

Useful reference: 420

When the flowering heads of this legume have been fertilized, they turn down into the ground and the fruit matures in the soil. The fruit is a pod commonly hearing two or three kernels. Each kernel consists of two large seed-leaves (cotyledons), between which lies the germ, and the whole is covered by a thin coat (skin). The empty pod is called hull, husk or shell. The fruit can be processed either without the hull (decorticated) or with the hull (undecorticated). The oilcake from undecorticated fruits is richer in fibre and lower in protein than the decorticated cake. It is also richer in residual oil as the hulls obstruct removal. To avoid this loss, the oil is often extracted by the solvent process.

AFLATOXIN. Mouldy groundnuts may contain toxic substances, and discoloured nuts with white flesh should be discarded. Aflatoxin, the most important toxin found in mouldy groundnuts, is produced by the fungus Aspergillus flavus. This fungus grows when the temperature is between 30 and 35 C and when the moisture content is above 9% in the kernels or above 15% in the oilcake. The attack of this fungus can be prevented, with minimum damage to the hull or kernel, by careful harvesting and by quick drying and storage in low humidity.

WHOLE GROUNDNUTS. "Hogging off" is the practice of allowing swine to feed on groundnuts, which they root out of the soil when turned loose in the field. This practice is not only used for cleaning up waste groundnuts after harvesting, but fields are also planted for this purpose, as it is a very cheap method of fattening pigs. It is necessary to supply the pigs with a mineral mixture that is high in salt and calcium. Ham from groundnut-fed hogs is softer and juicier than normal ham. This can be counteracted, however, by finishing the pigs on a ration containing cottonseed meal, which has the opposite effect from groundnuts. Whole groundnuts are excellent poultry feed and can constitute up to 25% of the diet.

GROUNDNUT CAKE. The decorticated cake and meal are safe feeds for all classes of livestock because of their good protein balance. For mature ruminants there are no restrictions on the use of groundnut cake. The high fibre content of undecorticated cake makes it a useful corrective for cattle feeding on grass that is low in fibre.

The residual oil in groundnut cake may cause soft fat in bacon pigs; therefore, the extracted decorticated meal is preferable for pig feeding. To avoid soft body fat, the feeding of six parts milo chops or five parts maize meal for each part groundnut cake is recommended. Because of its low fibre and high protein content, decorticated groundnut meal is a valuable ingredient in poultry diets.

SKIN. The skin, which constitutes about 3% of the seed weight, is a by-product of the processing of peanuts for human consumption. It has a bitter taste and can only be used in small quantities in ruminant feeds.

HULLS. The hulls amount to 20-30% of the weight of the whole pod. They are often used first as poultry litter and later as feed for ruminants. They have also been used as a carrier for molasses feeds. As they contain over 60% crude fibre, they interfere with digestion, especially of protein, unless they are fed in very small amounts.

GERM. The germ is a by-product of groundnut paste (peanut butter). Although bitter in taste, it can be included in concentrates for ruminants and pigs.