Abstract
This study evaluates the antioxidative potential of crude and chemically modified polysaccharides derived from Lycium barbarum L. leaves to enhance the thermal stability of Extra Virgin Olive Oil (EVOO) during extended storage and heating. Natural polysaccharides were modified using ascorbic acid and hydrogen peroxide to improve their antioxidative properties, providing a potential alternative to synthetic antioxidants. EVOO samples treated with these polysaccharides were subjected to accelerated oxidation at 60 °C for eight weeks to simulate extended storage conditions. Oxidative stability was assessed through multiple parameters, including peroxide value (PV), P-Anisidine value (p-AV), acidity value (AV, calculated as twice the free fatty acid content), iodine value (IV), and free fatty acids (FFA). Results showed that modified polysaccharides significantly improved the oxidative stability of EVOO. After eight weeks, the peroxide value of EVOO treated with modified polysaccharides decreased by 35 % compared to the untreated control, and the free fatty acid content remained at 0.46 %, well below the European Union limit of 0.8 %. Additionally, the modified polysaccharides demonstrated 95.2 % DPPH radical scavenging activity, significantly higher than the 88.7 % observed for crude polysaccharides (p < 0.05). These findings suggest that chemically modified Lycium barbarum polysaccharides can serve as effective natural antioxidants, enhancing edible oils' shelf life and thermal stability. This study provides a practical approach for applying natural antioxidants in the food industry, potentially reducing the need for synthetic additives in high-temperature food processing and extended storage.