Resistance to oxidation of Pentaclethra macrophylla Benth oils store for six months.

Most existing oils are of vegetable origin. Oils extracted from seeds (such as olive, peanut, sesame, rapeseed, maize, sunflower, soybean) by chemical solvents undergo, during their conservation, oxidative alteration leading to the loss of their oxidative potential. Oils extracted by mechanical processes (pressure associated to centrifugation or not) naturally contain more antioxidant substances (tocopherols, polyphenols, etc.), than refined oils, which protect them from oxidation. Lipid oxidation is the principal factor limiting the lifetime of oils rich in polyunsaturated fatty acids and contributes to diminishing their nutritional value. In the present study, oils extracted, from the Pentaclethra macrophylla Benth seeds, by pressure and by solvent, were compared on their fatty acids content and their oxidation resistance during six months of storage. Peroxide value increased for oils extracted by solvent whereas acid value revealed low number for both types of extracted oils. Oils extracted by pressure and stored for six months were more resistant to the oxidative stress imposed by the rancimat method. Unsaturated fatty acid content, determined by gas chromatography, showed a regression compared to saturated fatty acids, in both cases. The analysis of variance did not reveal significant difference, at 5% levels, in fatty acids content during six months of storage in both types of oils. Télécharger l'article