Evaluation of antioxidant activity of some plant extracts and their application in biscuits

Natural antioxidants have gained considerable interest in recent years for their role in preventing the auto oxidation of fats, oils and fat containing food products. In the present study, three plant foods viz., amla (Emblica officianalis), drumstick leaves (Moringa oleifera) and raisins (Vitis vinifera) were used as sources of natural antioxidants. All the three extracts exhibited a high percentage of antioxidant activity evaluated using β-carotene–linoleic acid in vitro system, compared to synthetic antioxidants. Biscuits prepared by addition of natural extracts were subjected to sensory studies and chemical analysis. Biscuits treated with natural antioxidants, extracted from raisins (B4) and drumstick leaves (B5) received higher (P ⩽ 0.05) panel scores during storage period of 6 weeks, than control (B1), butylated hydroxyl anisole (BHA) (B2) and amla (B3) extract incorporated biscuits. Addition of plant extracts from the three plant foods gave an excellent antioxidant effect on the biscuit compared with the effect of BHA, as the % increase in both peroxide and acid values after 6 weeks were lower than that of the control and BHA treated samples. Extracts from drumstick leaves and amla were more effective in controlling lipid oxidation during storage.