식용유지 자동산화의 온도 의존성

초록

Temperature dependence of autoxidation of soybean, sunflower, and olive oils was compared. The oils were stored at 25, 40, 60, or 80℃ in the dark. Degree of oxidation was determined by peroxide(POV) and p-anisidine values(PAV), and fatty acid composition. Antioxidant contents of the oils during storage were also monitored by high performance liquid chromatography and spectrophotometer. POV and PAV of the oils increased with storage time and storage temperature. The values were highest in sunflower oil followed by soybean and olive oils. Activation energies (Ea) for autoxidation of soybean, sunflower, and olive oils were 17.56, 19.00 and 12.48 Kcal/K mol, respectively, indicating higher temperature-dependence of sunflower oil than that of soybean or olive oil. Tocopherols, initially present at 684, 290, and 104 ppm in soybean, sunflower and olive oils, respectively, were degraded during storage. Olive oil showed the highest tocopherol degradation rate with storage time ; however, presence of polyphenols (550ppm) and their high stability during storage contributed to higher oxidative stability of the oil.