Vegetable oils oxidation: mechanisms, consequences and protective strategies

Vegetable oils are key ingredients of the human diet, as they are widely used for cooking and as ingredients in many processed foods. However, processing may lead to their oxidation and result in an array of negative outputs such as the development of undesirable organoleptic characteristics (e.g. off-flavors and texture alteration), a decrease in nutritional value, shelf-life and even in the formation of toxic compounds. Many strategies for improving oil stability have been developed such as the use of natural and synthetic antioxidants, and more recently the use of encapsulation techniques. It has many beneficial effects due to the barrier effect it establishes between the oil and the environment; this not only protects the oils against chemical reactions and physical changes but maintains their biological and chemical characteristics. This review is divided into three parts. In the first, the mechanisms of oil oxidation and the factors responsible for oxidation are summarized. In the second part, the consequences of oxidation in oil quality and the production of potentially harmful decomposition compounds are reviewed. Finally, the addition of antioxidants and encapsulation techniques are also compiled as strategies to improve oils' oxidative stability.