Submitted to: Proceedings JOCS/AOCS World Congress
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 2003
Publication Date: February 15, 2003
Citation: ABIDI, S.L., RENNICK, K.A. EFFECT OF GAMMA-ORYZANOL MINOR OIL CONSTITUENTS ON THERMAL DECOMPOSITION OF FRYING OILS. PROCEEDINGS JOCS/AOCS WORLD CONGRESS. 2003. Abstracts. p.21. Technical Abstract: Gamma-Oryzanol is a mixture of minor chemical components of plant seeds. The compounds are known to exhibit antioxidative and hypocholesterolemic activities and are useful for stabilizing frying oils. In this study, polar fractions of refined-bleached-deodorized high-oryzanol rice bran oil (HORBO), rice bran oil (RBO), and partially hydrogenated soybean oil (PHSBO) used for French fried potatoes were isolated and evaluated for degradation products by high-performance size exclusion chromatography-evaporative light scattering detection. Separations of triglyceride-derived analytes were achieved by elution with tetrahydrofuran through mixed-bed polystyrene/divinylbenzene columns. Predominant formation of dimeric and monomeric materials was observed in all experiments with HORBO and RBO, while less amounts of polymeric species were produced from PHSBO. At the conclusion of frying duration, HORBO, RBO, and PHSBO yielded respective dimers, oxidized triglycerides, and diglycerides as the major decomposed species of the oils. The concentration distribution data for the nonvolatile components were indicative of variable degrees of polymerization of the oils: RBO>HORBO>PHSBO. This trend is in consistent with rationales based on lipid unsaturation and sterol antipolymerization. As predicted, HORBO invariably produced significantly less polymeric materials than RBO. Additional test data for percent polar materials and percent polymerized triglycerides supported that increasing oryzanol contents (HORBO>RBO>PHSBO) enhanced the quality and stability of frying oils.