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How do antioxidant preservatives protect foods containing fats and oils?

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Learn about food preservation and the various methods to preserve foodstuffs — food preservation An overview of food preservation.

Antioxidant preservatives protect foods containing fats and oils by interrupting the process of autoxidation, a chemical chain reaction that leads to rancidity.123

In these foods, unsaturated fatty acids react with oxygen to form highly reactive intermediate molecules known as free radicals. These radicals propagate a chain reaction that degrades fat molecules into volatile compounds, resulting in off-flavors and off-odors.132

Antioxidants function as free radical scavengers by reacting with these chain carriers, often by donating hydrogen atoms. This action terminates the oxidative chain reaction, thereby stabilizing the food and delaying the development of rancidity. Common antioxidants used for this purpose include:123

Natural compounds: Tocopherols (derivatives of vitamin E).14
Synthetic compounds: Butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and tertiary butylhydroquinone (TBHQ).142

Because the use of these additives can impact food safety and quality, their application is strictly regulated in most countries regarding both the type and quantity permitted.2