Edible oils consist of about 96% triacylglycerides, composed of different fatty acids. Some other compounds or groups of compounds, such as free fatty acids, phospholipids, phytosterols, tocopherols, other antioxidants or waxes, can also be found. Fatty acids, free or bound to glycerol are susceptible to oxidative processes resulting in a wide range of volatile and non-volatile degradation products.