The Stability of Carotene in Ethyl Esters of Fatty Acids, and in Liver and Vegetable Oils

McDonald, Francis G.

doi:10.1016/s0021-9258(18)75825-0

Cited by 10 publications

(2 citation statements)

References 4 publications

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“…It is on this point that the role of the unsaturation of the fat is not clear. Some reports have shown that increased unsaturation gives increased carotenoid stability (McDonald, 1933; Mitchell et al, 1954;Bickoff et al, 1955), while contrary reports have appeared claiming that unsaturated fats decrease stability (Budowski and Bondi, 1960;Lime, 1969;Blain and Shearer, 1963).…”

mentioning

confidence: 97%

Photocatalyzed oxidation of paprika pigments

Carnevale¹,

Cole²,

Crank³

1980

J. Agric. Food Chem.

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mentioning

confidence: 97%

Photocatalyzed oxidation of paprika pigments

Carnevale¹,

Cole²,

Crank³

1980

J. Agric. Food Chem.

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“…Since analysis of the concentrate showed that carotene formed only a small part of the,lipoidal constituents, it seemed of considerable importance to determine the effect of the other material on the utilization of the carotene as provitamin A, and to find out the effect of these other constituents on the stability of the carotene (2,16), Furthermore, since the concentrate contains an appreciable amount of sterols, it seemed of interest to find out something about their nature. Bethke, Kennard, and Kik (6) and Bechdel, Landsburg, and Hill (4) reported that green forage and artificially dried hay have no vitamin D activity.…”

Section: Constituents Of the Unsaponifiable Concentratementioning

confidence: 99%

Lipides Isolated from Alfalfa-Leaf Meal

Petering¹,

Morgal²,

Miller³

1941

Ind. Eng. Chem.

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A Hypothesis for Carotene Decolourization by a Free Radical Mechanism in Fatty Esters and Hydrocarbons

Venkatarao

Achaya

1969

Fette, Seifen, Anstrichm.

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Under oxidizing conditions, carotene is decolourized slowly in unsaturated and rapidly in saturated fatty esters. In unsaturated and saturated hydrocarbons, the reverse is observed. An explanation is offered based on the following hypotheses: a] That carotene is decolourized by hydrogen abstraction which upsets the entire conjugated hromophoric system and b] that the degree of internal stability of the substrate-derived peroxy-free radicals, which are the hydrogen-abstracting agencies, is inversely related to the life of carotene in that substrate. Eine Hypothese iiber die Entfarbung des Carotins d u d ein freies RadikalUnter oxydierenden Bedingungen wird das Carotin in ungesattigten Fettsaureestern langsam, in gesattigten r a s h entfarbt. In ungesattigten und gesattigten Kohlenwasserstoffen wurde das umgekehrte Verhalten beobahtet. Diese Ersdeinungen lassen sich durch folgende Hypothesen erklaren: a) Die Entfarbung des Carotins erfolgt durch Wasserstoffentzug, der das gesamte konjugierte chromophore System in Unordnung bringt und bJ der Grad der inneren Stabilitat der aus dem Substrat erhaltenen peroxydfreien Radikale, die als Wasserstoff entziehende Mittel dienen, steht mit der Lebensdauer des Carotins im betreffenden Substrat im umgekehrten Verhaltnis.Carotene dissolved in fats is known to decolourize with great rapidity under oxidizing conditions, and the process is hastened by light and heat. It was recorded long ago that the more unsaturated the fat, the greater the stability of carotene present in it 2, 3. This fact has not however been specifically accounted for in the generally-accepted theory of R. T. Holman4 that it is free radicals derived from unsaturated fatty substrates which attack the conjugated system of carotene and so destroy it by a coupled oxidation. This view is based on (a) delayed carotene destruction when antioxidants were also present in the fat systems, suggesting interception of free radicals; (b) co-oxidation of carotene with lipoxidase, a catalyst specific for the oxidation of unsaturated fatty acids containing cis nonconjugated double bonds; (c) oxidation with haematin compounds. -Carotene destruction has also been studied in hydrocarbon systems such as mineral oil5, and even used for comparing the efficiency of antioxidants E, ' . Destruction of carotene under the same experimental conditions both in fatty and in hydrocarbon substrates should enable an unified view to be developed of the mechanism involved.

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The Stability of Carotene in Ethyl Esters of Fatty Acids, and in Liver and Vegetable Oils

Cited by 10 publications

References 4 publications

Photocatalyzed oxidation of paprika pigments

Photocatalyzed oxidation of paprika pigments

Lipides Isolated from Alfalfa-Leaf Meal

A Hypothesis for Carotene Decolourization by a Free Radical Mechanism in Fatty Esters and Hydrocarbons

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