Rapid quantitation of thermal oxidation products in fats and oils by 1H-NMR spectroscopy.
This work describes the application of high-resolution proton nuclear magnetic resonance (1H-NMR) spectroscopy to the study of the thermal peroxidation of beef tallow and corn oil under standardized conditions. The approach provides a rapid, quantitative method for determining the degree of oxidation of unsaturated fatty acids in animal and vegetable fats and oils by quantitating the decreasing intensities of 1H-NMR peaks for allylic and olefinic protons in unsaturated fatty acid chains of triglycerides and the increasing peak intensities of hydroperoxide and saturated and alpha, beta-unsaturated aldehydic protons in relation to the less labile protons in the triglyceride molecule. Two-dimensional correlation spectroscopy analysis of highly oxidized beef tallow (180 degrees C for 24 h) suggested that the unsaturated aldehydes that persisted were apparently associated with carboxy groups.
Yang
C M
CM
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, ON, Canada.
Grey
A A
AA
Archer
M C
MC
Bruce
W R
WR
D000818:Animals; D002417:Cattle; D003314:Corn Oil / Q000737:chemistry*; D005223:Fats / Q000737:chemistry*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D014280:Triglycerides / Q000737:chemistry
D005223:Fats; D005231:Fatty Acids, Unsaturated; D014280:Triglycerides; D003314:Corn Oil; C013698:tallow; D006861:Hydrogen Peroxide