Propyl gallate is a food additive that serves as an antioxidant, primarily used to prevent or delay the spoilage of fats and oils in food products. It helps maintain the quality and extend the shelf life of various processed foods containing oils or fats, such as baked goods, snacks, and oils-based dressings. Propyl gallate is synthesized through esterification, where propyl alcohol is combined with gallic acid, a naturally occurring compound found in plants. The resulting propyl gallate is a white crystalline powder that can be added to food products to prevent oxidation and the resulting rancidity of fats and oils.