Bleaching Performance of Acid-Activated Clay for Refining Crude Palm Oil Bleached Deodorized Palm Oil with Clay from Sabongida-Ora, Owan West Local Government Area of Edo State, Southern Nigeria

Abstract

Locally sourced clays are cost-effective alternatives to commercial bleaching agents in edible oil refining. Acid-activated clay (AAC), produced by treating raw clay with mineral acids, enhances surface area and adsorption capacity, making it suitable for pigment and impurity removal. The objective of this paper is to determine the bleaching performance of acid-activated clay (AAC) to refine crude palm oil (CPO) to bleached deodorized palm oil (RBDPO) with clay from Sabongida-Ora, Owan West Local Government Area of Edo State, Southern Nigeria, using appropriate standard methods. The refractive indices (RI) obtained for the reference samples were 1.4637 and 1.4638, respectively. In comparison, the 5.0M H₂SO₄ activated clay showed RI values of 1.4630 0.00012, 1.4628 0.00010, 1.4633 0.00012, and 1.4633 0.00020, respectively. Similarly, the 5.0M HCl activated clay yielded RI values of 1.4630 010, 1.4632 0.00004, 1.4632 0.00060, and 1.4632 0.00004, respectively. The β-Carotene content of the reference oils was 126.305 and 166.81mg/Kg, while the AAC RBDPOs yielded higher values: 270.653mg/Kg (H₂SO₄) and 236.601mg/Kg (HCl), respectively. Notably, we observed a reduction in absorbance levels from 1.146 (CPO) to 0.074 (RBDPO). The highest colour removal (93.82%) was achieved using 15 g of H₂SO₄-activated clay. The close similarity of the test products to the reference samples in terms of RI and absorbance, along with a higher β-Carotene content, suggests that the test product may be viable as a new market-grade brand RBDPO.