Effects of Antioxidants on the Oxidative Stability of Oils Containing Arachidonic, Docosapentaenoic and Docosahexaenoic Acids

Abstract

AbstractThe effects of ascorbyl palmitate at 0, 300, 600, 900, or 1,200 ppm, tocopherol at 0, 200, 400, 600, or 800 ppm, and β‐carotene at 0, 3, 6, 9, or 12 ppm on the oxidative stabilities of Oil 1, Oil 2, and Oil 3 containing 0, 0.55, and 0.67% of combined arachidonic acid (AA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA), respectively, were studied by a central composite experimental design. The oxidative stability of oil was evaluated by determining the induction time using the Oxidative Stability Index. Ascorbyl palmitate and tocopherol had a significant effect on the stability of all three oils at α = 0.05. β‐Carotene did not have any effect on the stability of oils at α = 0.05. The interaction effect of ascorbyl palmitate and tocopherol was significant for the three oils at α = 0.05. The induction time of oils decreased as the total amounts of AA, DPA and DHA increased from 0 to 0.55% or 0.55 to 0.67%. The addition of 1,200 ppm ascorbyl palmitate, 800 ppm tocopherol and 12 ppm β‐carotene to Oils 1, 2, and 3 increased the induction time from 13.5 to 29.9 h, from 11.8 to 27.0 h, and from 10.5 to 20.0 h, respectively. The coefficient of determination (r2) for the linear regression between the experimentally determined and statistically predicted induction time of the three oils was greater than 0.95. The use of an optimum combination of ascorbyl palmitate and tocopherols from the response surface analysis could improve the oxidative stabilities of oils containing AA, DPA and DHA.