Antioxidants are both natural and artificial (synthetic) compounds which are capable to scavenge free radicals and to inhibit oxidation processes. However, artificial antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and tertiary butylhydroquinone (TBHQ) that have been widely used for preventing lipid peroxidation in several food products are gradually limited and controlled in the food
industry because they are suspected to be toxic and carcinogenic (Namiki, 1990). Therefore, the development and extraction of natural antioxidants from natural plants are more attractive and have been highly studied for new antioxidants. Many plants such as fruits and vegetables contain various phenolic compounds, which can possess antioxidant activity (Grigonis et al., 2005; Maisuthisakul et al., 2007). Several isolated plant constituents as well as crude extracts of fruits and vegetables have been well recognized as natural antioxidants that