Raw material preparationOilseeds an

Raw material preparation
Oilseeds and nuts should be properly dried before storage, and cleaned to remove sand,
dust, leaves and other contaminants. Fruits should be harvested when fully ripe, cleaned
and handled carefully to reduce bruising and splitting. All raw materials should be sorted to
remove stones and mouldy nuts. Some moulds,
especially in the case of groundnuts, can cause aflatoxin
poisoning. When storage is necessary, this should be in
weatherproof, ventilated rooms which are protected
against birds, insects and rodents. Some raw materials
(for example groundnuts, sunflower seeds) need
dehusking (or decorticating). Figure 1 shows a simple
manually-operated groundnut decorticating machine.
Decortication is important to give high yields of oil and
reduce the bulk of material to be processed. However,
expellers normally require a proportion of fibrous
material in order to work and, particularly with
groundnuts, some husk is normally added to allow oil to
escape more freely from the press. Coconut is
dehusked and split manually by skilled operators. Most
oilseeds (eg copra, palm kernels and groundnuts) need
grinding in mills before oil extraction to increase the yield of oil. A separate Technical Brief