Novel safflower oil with high γ-tocopherol content has a high oxidative stability

Abstract

Safflower oil, either with high linoleic acid or high oleic acid content, has a tocopherol profile dominated by α-tocopherol. Novel safflower germplasm that accumulates predominantly γ-tocopherol in seeds instead of α-tocopherol has been developed. The objective of this research was to evaluate the chemical properties and stability of safflower oil with high oleic acid and γ-tocopherol contents, produced by either mechanical pressing or solvent extraction from seeds of safflower line IASC-2. Safflower oil with high oleic acid and α-tocopherol contents from seeds of safflower line CR-6 was used as a control. Seeds of IASC-2 had low oil content (22.2% compared to 39.3%), which is the result of its wild origin. Oil samples showed only slight differences in the fatty acid profile and total tocopherol content. The predominant tocopherol form, either α- or γ, accounted in all cases for more than 95% of total tocopherols. Solvent extracted oils had more sterols than pressed oils, with oils from IASC-2 having higher sterol content than oils from CR-6. Major differences were observed for oil stability, measured with Rancimat. High γ-tocopherol pressed oil from IASC-2 had an induction period of 66.4h, compared to 38.0h for high α-tocopherol oil from CR-6, whereas solvent extracted oil from IASC-2 had an induction time of 121.0h, compared to 32.0h for oil from CR-6. Practical applications: Safflower oil, either with high oleic or high linoleic acid contents, has been traditionally valued as a healthy edible oil. The results of the present research indicated that the nearly complete replacement of α-tocopherol by γ-tocopherol has a great impact on enhancing oil oxidative stability. Oils with high oxidative stability are demanded for high temperature applications such as deep frying or biolubrication. Also, extended oxidative stability is required for biofuels. According to the results of this research, the novel safflower oil with high oleic acid and high γ-tocopherol content is more advantageous for such applications than safflower oils with high α-tocopherol content. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.