Effect of Light and Air on the Quality and Stability of Selected Vegetable Oils

The quality and stability of industrially processed palm, sunflower and cotton oils as affected by light and air were investigated. The oils exposed to light, air and both light and air were analyzed for physicochemical properties of acid value, free fatty acids and peroxide value over a period of four consecutive days. Determination of the acid values (AV), free fatty acids (FFA) and peroxide value (PV) was done by titration method while the data analysis employed SPSS statistical software. Results show that the effect of light and air on the deterioration of oils is statistically significant (p<0.05). The effect varied from one type of oil to another where as light and air contributed about 50:50 to the oil instability. The estimated marginal means of deterioration of the oils exposed to light and air were in the trend; sunflower > cotton > palm oil. Palm oil (saturated) showed higher stability compared to cotton and sunflower oil (unsaturated) that supports the argument that saturated oils are more stable to oxidation that unsaturated oils. This study recommends that the small scale oil sellers to purchase small packs of oils to avoid prolonged exposure of the oils to both light and air.