Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Abstract:
The study of dye-sensitized photo-oxidation of some vegetable oils was carried out to investigate the effect of light and dye- sensitizer (Methylene blue) on the quality of some vegetable oils. Reactive oxygen species occur in tissues and can can damage DNA, proteins, carbohydrates and lipids. Soyabean, groundnut, palm kernel and palm oils were each photo-oxidized in dichloromethane/methanol solution using methylene blue as sensitizer. The reaction was monitored by thin layer chromatographic measurements (TLC), followed by peroxide value measurements. The tlc of each of the reaction mixtures showed that some components were transformed to more polar compounds, some of which were in the oil prior to the photo-oxidations, and the order of reactivity of the oils was soyabean > groundnut > palm > palm kernel. The peroxide values of the oils increased by 65.6, 49.3, 42.5 and 36.6 meq/kg for soyabean, groundnut, palm kernel and palm oils respectively. The peroxide value increases averaged over the duration of each of the reactions gave rates of 10.9, 5.5, 3.5 and 2.8 meq/kg/h for soyabean, groundnut, palm kernel and palm oils respectively.

Keywords: soyabean oil, groundnut oil, palm kernel oil, palm oil, photo-oxidation, singlet oxygen.

Download full paper