GCOML’s vegetable oil processing

For years, the Jos-based Grand Cereals and Oil Mills (GCOML) Ltd, an arm of UAC Plc, has been at the forefront of processing delicious and health-promoting vegetable oil, from both soya beans and groundnut. In fact, some years back its Grand Pure Soya oil was confirmed as the most heart-friendly vegetable oil in the country by the Nigeria Heart Foundation (NHF), with the tacit approval from the Geneva-based parent body in a grand ceremony in Lagos.

This was what prompted the visit of this writer to find out the processes that have accorded the product its appealing high quality. It was during that visit that the then Assistant Oil MILL Manager of GCOML, Paul Chogi, a graduate of the University of Jos with a bachelor’s degree in Food Technology gave details of all the steps involved.

The Processes

(a) Removal of impurities

The soya beans come from Gboko while the ground nuts are brought in from Katsina and Kano. The impurities which have to be removed include stones, fine sand, dust and sticks. The separation of extraneous materials is done on the basis of the different sizes. The two screens used include the upper and the lower types. The uppers one removes the stones and sticks. The lower screen is aspirated to remove the lighter particles.

Another cleaning stage follows. Here the de-stoner removes stones which are of the same size as the soya beans or groundnut seeds. This is based on the difference on the basis of weight instead of size as was during the first stage of screening. The vibration of the slanted deck makes it possible for the stone to be collected through the spout at the back.

The cleaned seeds are sent to the Roller Mill for size reduction, with the smaller particles ensuring larger surface area for effective cooking.

(b) High Temperature cooking for oil extraction

These are passed through the conveyors to the elevators which deposit them in the two cookers. There is steam application at the second stage of the 5 – stage cooker where the temperature is increased to 105 0C.

This high temperature cooking is to effectively remove trypsin, the inhibiting enzyme. Thus the oil is released easily from the seeds especially during pressing. Under pressure there is extraction of the oil, which is squeezed out of the seeds. For soya beans, the cake comes out and it is used for animal feeds. Mealia is formed using soya beans (protein) in combination with maize (carbohydrate).

The oil is mixed with the cake. While the cake goes for bagging, the oil with cake is re-circulated back to the cooker at the vibrating screen. There, the oil goes down for filtration at the filter press while the cake is also recycled.

(c) Refining the oil

The crude vegetable oil is sent to the refinery. Crude oil from the storage tank is conveyed to the neutralizer to undergo the first stage of refinery. At this crucial stage, phosphoric acid is added to remove gum or phospholipids at calculated dosage.

Sodium hydroxide is also added to remove free fatty acids which are injurious to human health. The stirrer is used to effectively combine fatty acids and soda to produce the soap stock containing insolvent impurities.This is separated from oil and sold to local soap makers.

The oil produced is now free from gum fatty acids. Clean water is used to wash away the phosphoric acids and sodium hydroxide thoroughly. This ensures that the oil does not have a soapy feeling .The oil goes to the Bleacher where bleaching earth is used to reduce the colour (to make it lighter). The oil is deodorized (to remove any offensive odour) from soya beans at 200 degrees Celsius under vacuum. The oil is cooled to between 30 to 40 degrees Celsius.

At this point the oil is ready for consumption. There are 2 filling lines. The mill has the capacity to produce 1000 tins of groundnut or soya beans oil per day, depending on request from the market. The packages come in 1 litre, 3 litres, 4 litres and 18 litres.

All these technical processes lead to the production of GRAND PURE SOYA OIL and GRAND PURE GROUNDNUT OIL which are clear, odourless and do not foam or fume. These attributes, which come as a result of careful selection of the seeds and the subsequent high-pressure cooking and oil refining using state-of-the art machinery confer on both vegetable oils their market leadership.

Nutritional benefits:

Soya beans’ efficacy against stroke and cancer

Apart from promoting a healthy heart, several researches have attested to the power of oil and milk extracted from soya beans in staving off the debilitating effects of stroke and cancer.

For instance, recent research studies carried out by Japanese scientists have identified the power of linoleic acid in soya beans oil in reducing stroke, especially that caused by blood clots(ischemic strokes). From the studies conducted on 7,450 Japanese men and women between the ages of 40 and 85,it was shown that for every 5 per cent increase in linoleic acid in their diet there was 28 per cent reduction in the risk of either type of stroke and 34 per cent drop in the risk of clot-related stroke and 19 per cent decline in hemorrhagic stroke.

The commendable role of the fatty acid is in the reduction of inflammation and regulation of blood pressure was well noted. Linoleic acid improves glucose tolerance, helps to lower blood cholesterol level, thereby increasing blood circulation.

As for reduction in breast cancer in women, years of studies have shown that Asian women,who consume more soya beans products have much lower breast cancer risks than their western counterparts. According to researchers at the University of Texas Medical Branch in Galveston and Weizmann Institute of Science in Rehovol, Israel soy beans-rich Asian diets have been found to inhibit the development of breast malignancies.

Soy milk, for instance is relatively rich in genistein and daidzein, a pair of plant estrogens or phytoestrogens. They bind to and activate specific receptors on cells throughout the body. And all because estrogen can promote and fuel the growth of many breast cancers, diets rich in phytroestrogens might effectively starve pre-cancerous tissues, diminishing a woman’s cancer risk.