G.K.  Fekarurhobo, F.G.  Obomanu, 
    Effects of Short-Term Exposure to Sunlight on the Quality of Some Edible Vegetable Oils,
    Research Journal of Applied Sciences,
    Volume 4,Issue 5,
    2009,
    Pages 152-156,
    ISSN 1815-932x,
    rjasci.2009.152.156,
    (https://makhillpublications.co/view-article.php?doi=rjasci.2009.152.156)
    Abstract: The effects of ambient sunlight on the quality of oven-dried palm, palm kernel, groundnut and soybean oils were determined by exposing them to sunlight for 25 days. Physico-chemical measurements made at 5th day intervals shown that their relative density, viscosity, peroxide, refractive index and free fatty acids values increased in the order soybean oil>groundnut oil>palm oil>palm kernel oil, while their iodine values were found to decrease in the same order. The increase/decrease in each of the values were significant when compared to those found for their respective unexposed (i.e., control) oil samples. The variation of the values between the exposed and the unexposed samples in each oil was correlatable to the degree of unsaturation in the oil. There was reduction of colour intensity in all of the exposed oil samples.
    Keywords: Sunlight;soybean;groundnut oil;palm oil;palm kernel oil;photo-oxidation