Deposition of dietary epoxides in tissues of rats

Epididymal fat pad lipids from rats fed trivernolin at the 4.8% level in the diet for 90 days were found to contain 6.1% epoxyoleic acid. No epoxides were detected in the serum lipids and only trace amounts were found in the liver lipids. TLC, GLC and a specific color reaction with picric acid were used to identify this fatty epoxide in the tissues. Epoxyoleic acid was shown to be present as a mixture of predominately monovernoloyl triglycerides with some divernoloyl triglycerides and small amounts of trivernolin. Lipase hydrolysis of the first two triglycerides has demonstrated that the vernoloyl groups are present mostly in the 1,3 positions. In a separate experiment, rats were fed cholesterol epoxide at the 0.5% and 1.5% levels in the diet for 90 days. TLC and GLC examination of lipids from these rats failed to reveal the presence of any cholesterol epoxide. Only one-half of the sterol fed could be accounted for in the fecal lipids. Presented in part at the AOCS Meeting, Chicago, October 1967.     

Use of pulsed nuclear magnetic resonance to predict emulsion stability

Pulsed nuclear magnetic resonance (NMR) was used to measure extent of oil solidification during cooling of oil-in-water emulsions. “Percent interaction,” derived from these measurements, was found to correlate well with actual resistance of the emulsion to creaming and phase separation during storage. Average oil droplet size gave a fair correlation with stability, but the correlation of required Hydrophile-Lipophile Balance (HLB) with stability was poor. Pulsed NMR cooling curve measurements on emulsions offer an improved method for prediction of emulsion stability. Presented at the AOCS Meeting in Chicago, September 1976.     

Metabolic fate of epoxycholesterol in the rat

The rate of disappearance of intubated epoxycholesterol from the rat gastro-intestinal tract has been determined. The loss of this sterol is accompanied by the appearance of a sterol metabolite. This was isolated by preparative GLC and TLC and identified by mass spectrometry as 5α-cholestan-3β-5α, 6-β-triol. Presented in part at the AOCS Meeting, San Francisco, April 1969.     

Sterol additives as polymerization inhibitors for frying oils

Addition of certain vegetable oil unsaponifiables to safflower oil protects it from oxidative polymerization during heating at frying temperature. The unsaponifiables isolated from olive, corn, wheat germ andVernonia anthelmintica oils were found to be effective. The fraction responsible for this effect is largely sterol in nature. Although the common plant sterols show no antioxidant activity, the 4-α-methyl sterols function well. The sterols fromVernonia oil, which contain no 4-α-methyl group, are also active. It appears that an isofucosterol side chain may be the structural feature required to obtain this protective effect.     

Lactones in autoxidized vegetable oils

It was demonstrated that bothgamma anddelta saturated lactones are present in highly peroxidized vegetable oils. In the oils which were investigated thegamma isomers are predominant. Additional lactones also form when the hydroperoxides are reduced. Although no lactones were detectable in fresh, refined soybean oil, considerable amounts of bothgamma anddelta lactones were found to be present in highly peroxidized samples of cottonseed and soybean oils. The lactones in the peroxidized oils were concentrated by column chromatography on silica gel and by vacuum distillation. Gas-liquid chromatography was used for separation and identification. This has been supplemented by thin-layer chromatography, infrared spectrophotometry, and nuclear-magnetic-resonance spectrometry. Presented at the AOCS Meeting, Philadelphia, October 1966.