As people's living standards increase, so does the demand for ready-to-eat foods. Recently processed food has become very diversified and the number of food additives used in production has increased. In many foodstuffs, spontaneous reactions called oxidation occur between the components of the food product and the oxygen present in the air. As a result of such reactions, color, odor and flavor changes occur in the food product and the quality of the food products decreases. This often leads to poisoning. If oxidation status cannot be prevented by physical and technological methods, antioxidants are used.

Antioxidants are compounds that prevent or delay oxidation in foodstuffs. These compounds give hydrogen due to their phenolic structure and suppress oxidation, which prevents the formation of free fatty acids. The most commonly used antioxidants that act in this way are:

• Butylated hydroxyanisole (BHA)
• Butylated hydroxytoluene (BHT)
• Propyl gallate (PG)
• Tertiary butyl hydroquinone (TBHQ)

Animal fats do not have any protection against oxidative action. In contrast, most vegetable oils contain natural antioxidants. Therefore, stabilization of animal fats such as bovine fat, lard and chicken fat is important. An additional protective effect is obtained by using antioxidants in vegetable oils.

Within the scope of chemical food analyzes, antioxidant substances in oils (BHA, BHT, PG, OG and TBHQ) are determined by authorized laboratories. Generally, high performance liquid chromatography method (HPLC) is used in these studies. In HPLC studies, mobile phase is given at high pressure and high resolution separation is provided. The HPLC method gives precise results in the separation of non-volatile or easily degradable chemical compounds at temperature. In the determination of antioxidant substances in oils, standards published by domestic and foreign organizations are also complied with.