Quality of nigerian palm oil after bleaching with local treated clays

Laboratory investigations into the possibility of using local Nigerian clays in refining the Nigerian crude palm oil revealed that the Okija clay may possess some potential as an adsorptive cleanser in the refining process. Activated bentonite was used as the standard clay of comparison, and the performance of two local natural clays, leached with various concentrations of sulfuric acid, was evaluated for their use as alternative adsorptive cleansers in refining Nigerian crude palm oil. Measurements of peroxide values, para-anisidine values, carotene content and stabilities of the oils using the active oxygen method were used in assessing the relative performance of the clays. The clays exhibited similar trend of effects on identical batches of alkali-neutralized palm oil. In one set of experiments poor results were obtained when the degummed and alkali-neutralized palm oil was treated with clays leached with sulfuric acid at concentrations of 1M and 4M. Better results were obtained at acid concentrations of 2M and 3M. Bentonite proved better than Okija clay when the leaching was performed with 2M H₂SO₄, but both clays had comparable effectiveness when 3M H₂SO₄ was used for leaching. The Nsu clay gave the least encouraging results. In another series of experiments the results showed that for various dosages of clay, up to 3% by weight of the oil to be refined, the oxidative stability of the processed oil was reasonably good for an oil which was neither deodorized nor treated with antioxidants.