Low-temperature autooxidation in unsaturated lipids: an electron spin resonance study

Journal Article · Thu Jan 15 04:00:00 EST 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100286a044· OSTI ID:6812786

Yanez, J; Sevilla, C L; Becker, D; Sevilla, M D

An electron spin resonance (ESR) study of the low-temperature autooxidation of lipids is reported in this work. Free radicals were generated at 77 K in the unsaturated lipids by means of UV photolysis of the lipid hydroperoxides normally found in these materials. For saturated lipids radicals were initiated either by photolysis of samples containing a small amount of added peroxide or by ..gamma..-irradiation. The initial radicals formed by photolysis (RO, OH) rapidly abstract from the lipid to form carbon-centered radicals. Annealing samples to temperatures which allow for molecular oxygen migration results in the formation of peroxyl radicals. The temperature at which oxygen migration starts is dependent on the lipid. For unsaturated lipids loss of LO/sub 2/ with further annealing resulted in a concomitant production of the lipids allylic or pentadienyl radicals. In experiments with linolenic acid reintroduction of oxygen then results in formation of the lipid peroxyl radicals at low temperatures and the continued observation of the pentadienyl radical at higher temperatures. This is explained in terms of relative rates of oxygen migration and abstraction reactions. In the case of saturated lipids no new radicals appear with the loss of the peroxyl radicals. These results are discussed in light of previous work.

• Research Organization: Oakland Univ., Rochester, MI
• OSTI ID: 6812786
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:2; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ELECTRON SPIN RESONANCE
ESTERS
EXPERIMENTAL DATA
INFORMATION
KINETICS
LIPIDS
LOW TEMPERATURE
MAGNETIC RESONANCE
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDATION
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADIATIONS
REACTION INTERMEDIATES
REACTION KINETICS
RESONANCE
TRIGLYCERIDES
ULTRAVIOLET RADIATION