Groundnut

 (i) Threshing:- The removal and separation of Groundnut vines from the pods.

(ii) Shelling/Decortication:- This involves the breaking of the shells and separating the broken shell from the seeds (decortication)

(iii) Seed grading:- This involves the separation of different size range of Groundnut seeds to enable preparation of seeds for mechanical planting and or for export of the commodity

(iv) Seed chemical mixing:- This involves mixing, sorting, and grading groundnut seeds with chemical seed dresser

(v) Roasting:- This is the process where by the seed, are fried to enable quick polishing and easier oil extraction

(vi) Polishing:- This involves removal of seed coat or testa from the seeds

(vii) Grinding or Pasting:- this is the process of turning the roasted polished, and cleaned groundnut seed into paste.

(viii) Oil extraction:- This is the process of removal of oil from the groundnut paste

Extraction Processes

There are principally two methods of oil extraction, with a third, which is a combination of the two methods.

1. Mechanical Extraction

Screw presses or expeller and hydraulic presses are the common machines used. Basically both machines extract oil from pretreated groundnut by subjecting the oil bearing material to pressure.

The main components of the screw press is a horizontal crank shaft (which can be single or double). There seems to be a general preference for hydraulic press than the screw press.

1. Solvent Extraction

This is achieved by either percolation or total seed immersion or a combination of both. Most solvent extraction employ percolation method. The solvent commonly used is hexane, because of its

toxic acceptability.

iii. Combination of Mechanical and Solvent Extraction

In this process part of the oil is removed by pressing and the oil left in the cake is then extracted by solvent.

Post-extraction process

(i) Refining

The outputs of the processes discussed above are crude oil. To add value and improve their qualities, the oil need to be refined. The essence of refining is to obtain a product with the desirable colour, taste, smell and stability.

(ii) Groundnut Butter

Groundnuts are first shelled and cleaned. They are then roasted at 2180C for 40 – 60 minutes either (a) on rays in an oven. The nuts being turned by hand from time to time or (b) in equipment similar

to that used for roasting coffee. The roaster allows each nut to become uniformly roasted. After roasting, the nuts will be well browned and the skins loose after cooling, it is necessary to

remove the skins by gentle brushing, an inspection will allow the manual removal of dis-coloured and other rejected material.

In Nigeria and other African countries, groundnuts are used as snacks in the form of roasted in shells or in

shelled seeds, cooking oil, cake and peanut butter delicacy. In U.S. and Europe, groundnuts are mainly used as salted, dry roasted, speciality nuts (such as honey roasted hickory smoked or chilli flavoured) snacks, peanut butter confectionery and chocolate – based products.

About 48% of the world output of groundnuts is being used as food and 52% is crushed to produce oil and cake. In Asian countries, large amount of groundnuts are consumed as sauce (Satay) and

gravies. Nigeria is a huge market for groundnut products, some of which are imported from neighbouring countries. The availability of  groundnuts in Nigeria, coupled with technology of processing it into various products provide opportunities and economic fortune to farmers, industrialists, and prospective

entrepreneurs. Investment opportunities exist in the processing of cooking oil, cake, peanut butter, roasted salted and coated nuts, and production of a number of chocolate-based products. Other investment opportunities are in the  establishment of oil containers, storage facilities production of oil processing equipment (oil expellers & solvent extraction equipment), processing of kernels for activated charcoal, and the use of cake in the composition of animal feeds.