Physico-Chemical Properties, Composition, and Oxidative Stability of Olive and Soybean Oils Under Different Conditions

Commercial olive and soybean oils have been analyzed periodically in order to evaluate the influence of storage conditions on quality. The following parameters were determined every 10 days of storage: peroxide, saponification and acid values, absorption coefficients K-270 and K-232, phenols, chlorophylls and carotenoids contents, DPPH scavenging ability, and total antioxidant activity. Edible oils were exposed to daylight and stored at room temperature in different containers with the same surface area of exposure to air either in clear glass or opaque glass bottles. Changes in oils properties were also examined after the addition of Vit-E as an antioxidant in oil samples. The results showed a gradual loss of quality during storage, especially in clear glass bottles. The addition of the antioxidant, however, significantly reduced the deterioration and oxidation rate in the oil. The best containers for commercial packing of oil were opaque glass bottles containing antioxidant products.