Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/4/2014
Publication Date: 5/7/2014
Citation: Winkler-Moser, J.K., Hwang, H., Bakota, E.L. 2014. Interesting effect of phytosterol structure on antioxidant activities of phytosteryl ferulates [abstract]. American Oil Chemists' Society.
Technical Abstract: In nature, phytosteryl ferulates usually occur as mixtures where the profiles of the phytosterols are influenced by the cereal source. When evaluating phytosteryl ferulates from corn and rice as potential antioxidants for frying, we found that phytosteryl ferulates from corn were superior to those from rice. To understand why, steryl ferulates were synthesized from pure commercial sterols with different structural features, including saturated sterols, double bond at the 5C-position, and the 4,4’-dimethyl group common to rice phytosteryl ferulates. The antioxidant activities of these synthetic steryl ferulates were compared to rice phytosteryl ferulates by several methodologies, including by in vitro antioxidant assay, by oxidative stability index (OSI) of soybean oil, and by analysis of antioxidant activity during frying. Synthetic steryl ferulates and oryzanol did not differ much in antioxidant activity in vitro or by OSI. However, in their evaluation as frying oil antioxidants, steryl ferulates with a saturated sterol group had the best antioxidant activity, followed by sterols with one double bond in the C5 position. The results indicate that a dimethyl group at C4 as well as a C9, C19-cyclopropane group, as found in rice steryl ferulates, negatively affects antioxidant activity in frying oils.