Evaluation of Antioxidant Strategies in Low-Moisture Foods

Abstract: Lipid oxidation is the primary source of off- flavors, aromas and nutritional degradation in fat rich foods and poses a great obstacle to food manufacturers working to maintain food safety and shelf life. Lowmoisture, baked or deep-fried snacks are the main source of saturated fat in consumers’ diets and substituting these saturated fats with unsaturated fats is a major challenge in delivering healthier snacks. This study followed industrial cracker model using interesterified soybean oil to understand oxidative stability and evaluated various antioxidants proven to be efficient in other lipid-based model systems. As low-moisture foods are typically in opaque packaging, light-induced lipid oxidation is less likely. Hence, antioxidant strategies here require a focus on effective free radical scavengers. Lipid hydroperoxides and hexanal formation were used as indicators of oxidation. The effects of mixed tocopherols (500, 1000 and 5000 µmol/kg cracker) and phosphatidylethanolamine (200, 500, 1000 and 2000 µmol/kg cracker) were evaluated. Mixed tocopherols (500 µmol/kg cracker) improved the oxidative stability of the crackers. However, higher concentration (5000 µmol/kg cracker) resulted in faster lipid oxidation due to endogenous antioxidants in the oil. Phosphatidylethanolamine (2000 µmol/kg cracker) resulted in the best antioxidant treatment of all due to the presence of endogenous antioxidants. In a stripped oil model, mixed tocopherols and phosphatidylethanolamine in the range of 200-1000 µmol/kg cracker resulted in oxidative stability proportional to antioxidant concentrations. Concentrations combining high phosphatidylethanolamine and low mixed tocopherols were effective in delaying lipid oxidation. A primary model study tested functionality of myricetin with mixed tocopherols, at a concentration of 500 µmol/kg of cracker for each antioxidant. Myricetin demonstrated effective antioxidant activity individually and increased protection in combination with mixed tocopherols. This research is significant for food industry since it presents novel strategies to improve oxidative stability of unsaturated fats in snacks and provides direction for future research.