The oxidation of α-tocopherol during the autoxidation of ethyl oleate, linoleate, linolenate, and arachidonate

Witting, Lloyd A.

doi:10.1016/0003-9861(69)90160-x

Cited by 34 publications

(8 citation statements)

References 29 publications

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“…Evans and others (1959) reported that once a large amount of hydroperoxides had accumulated in oil, the rapid oxidation of tocopherol occurred. The higher the ratio of hydroperoxides to tocopherol concentration, the greater the loss of tocopherol in soybean oil (Witting 1969). Gregory (1996) reported that the tocopherol degradation rapidly increased in the presence of oxygen and free radicals in foods.…”

Section: Resultsmentioning

confidence: 99%

Stability of α‐, γ‐, or δ‐Tocopherol during Soybean Oil Oxidation

Player¹,

Kim²,

Lee³

et al. 2006

Journal of Food Science

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The decomposition of α‐, γ‐, or δ‐tocopherol in soybean oil during 24 d of storage at 50 °C was determined by high performance liquid chromatography (HPLC). The initial contents of α‐, γ‐, and δ‐tocopherol in soybean oil were 53, 750, and 268 ppm, respectively. The degradation rates of α‐, γ‐, and δ‐tocopherol for the first 10 d were 5.6%, 1.2, and 0.5% per day, respectively. The α‐tocopherol was completely destroyed in 16 d. The destructions of γ‐ and δ‐tocopherol were 28% and 17% after 24 d. The induction period of soybean oil determined by headspace oxygen, conjugated diene, and peroxide value was 8 d. As the degradations of α‐, γ‐, and δ‐tocopherol increased, the headspace oxygen disappearance, conjugated diene formation, and peroxide value of soybean oil increased. The correlation coefficient between the degradation of tocopherols and the oxidation of soybean oil was about 0.95. The degradation of tocopherols in soybean oil during storage was due to the oxidation.

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Section: Resultsmentioning

confidence: 99%

Stability of α‐, γ‐, or δ‐Tocopherol during Soybean Oil Oxidation

Player¹,

Kim²,

Lee³

et al. 2006

Journal of Food Science

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“…Complete tocopherol consumption is not always a necessity for the transition from the induction period to the rapid oxidation phase. As suggested by Witting [47], this transition is determined by the ratio of tocopherols to the degree of oxidation already reached, i.e. the amount of hydroperoxides present.…”

Section: Tocopherol Contents and Oxidative Stabilitymentioning

confidence: 94%

Effect of fatty acids and tocopherols on the oxidative stability of vegetable oils

Kamal‐Eldin

2006

Euro J Lipid Sci & Tech

236

175

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Effect of fatty acids and tocopherols on the oxidative stability of vegetable oilsThe oxidative stability of vegetable oils is determined by their fatty acid composition and antioxidants, mainly tocopherols but also other non-saponifiable constituents. The effect of fatty acids on stability depends mainly on their degree of unsaturation and, to a lesser degree, on the position of the unsaturated functions within the triacylglycerol molecule. Vegetable oils contain tocopherols and tocotrienols, especially a-and gtocopherols, as their main antioxidants. The antioxidant behavior of tocopherols represents a complex phenomenon as they are efficient antioxidants at low concentrations but they gradually lose efficacy as their concentrations in the vegetable oils increase. The "loss of efficacy" of tocopherols, sometimes referred to as a "pro-oxidant effect", is witnessed by an increase in the rate of oxidation during the induction period, despite elongation of this phase. The phenomenon is much obvious for a-tocopherol, but is also evident for other tocopherols. In agreement with nature's wisdom, the tocopherol levels in vegetable oils seem to be close to the optimal levels needed for the stabilization of these oils. The presence of other antioxidants in the oils, e.g. carotenoids, phenolic compounds, and Maillard reaction products, may synergize with tocopherols and minimize this loss of efficacy.

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“…The antioxidative efficiency of a-tocopherol decreases with increasing degree of unsaturation. For example, the relative efficiency of a-tocopherol decreases from 40 for C18:1 to 1 for C18:2, 0.5 for C18:3 and 0.25 for C20:4 [9]. In addition to other antioxidants, synergistic compounds, which reinforce the activity of chain-breaking antioxidants, and chelating compounds for binding of divalent cations like trace metals are efficient in retarding lipid autoxidation.…”

Section: Introductionmentioning

confidence: 99%

Efficient stabilization of bulk fish oil rich in long‐chain polyunsaturated fatty acids

Drusch¹,

Groß²,

Schwarz³

2008

Euro J Lipid Sci & Tech

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The aim of the present study was to systematically investigate the possibilities of stabilizing a bulk oil rich in long-chain polyunsaturated fatty acids under ambient conditions. Combinations of different antioxidants (a-, g-and/or d-tocopherol, rosmarinic acid and rosemary extract rich in carnosic acid) as well as lecithin and citric acid were systematically investigated. Efficient stabilization was achieved by choosing a combination of tocopherols rich in g-or d-tocopherol and low in a-tocopherol, by including tocopherolsparing synergists like ascorbyl palmitate and carnosic acid from rosemary extract and metal-chelating agents. For carnosic acid, a concentration of 400 mg/kg oil provides sufficient protection; the concentration of the metal chelator should be adapted to the concentration of metal ions present in the oil. As an alternative ingredient with metal-chelating and tocopherol-sparing activity, lecithin may be included in the formulation, but its poor solubility in bulk oils limits its use.

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The oxidation of α-tocopherol during the autoxidation of ethyl oleate, linoleate, linolenate, and arachidonate

Cited by 34 publications

References 29 publications

Stability of α‐, γ‐, or δ‐Tocopherol during Soybean Oil Oxidation

Stability of α‐, γ‐, or δ‐Tocopherol during Soybean Oil Oxidation

Effect of fatty acids and tocopherols on the oxidative stability of vegetable oils

Efficient stabilization of bulk fish oil rich in long‐chain polyunsaturated fatty acids

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