Oxidative stability of conjugated linoleic acids relative to other polyunsaturated fatty acids

Zhang, A.; Chen, Z. Y.

doi:10.1007/s11746-997-0086-0

Cited by 76 publications

(49 citation statements)

References 6 publications

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“…In this context, antioxidative properties [2][3][4][5][6], no effect or even prooxidant activity [7,8] has been reported. Likewise, studies on the oxidative stability of CLA and its non-conjugated counterpart, LA (linoleic acid), are also contradictory, showing either higher susceptibility of CLA [9][10][11][12], similar behavior of CLA and LA [13] or lower oxidative stability of CLA than that of LA [14] in model systems including free fatty acids, methyl esters, ethyl esters and triacylglycerols. The great variety of oxidation conditions (temperature, oxygen availability, light-dark, etc.)…”

Section: Introductionmentioning

confidence: 99%

Differences in Oxidation Kinetics Between Conjugated and Non‐Conjugated Methyl Linoleate

Luna

Fuente

Salvador

et al. 2007

Lipids

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The oxidation kinetics of conjugated methyl linoleate was compared with that of non-conjugated methyl linoleate under mild oxidation conditions (30 degrees C in the dark). Samples of methyl 9-cis,11-trans-linoleate, methyl 10-trans,12-cis linoleate and methyl 9-cis,12-cis linoleate were assayed separately and in mixtures. For comparative purposes, methyl alpha-linolenate and methyl oleate were also used. Two complementary analytical approaches were selected to monitor the progress of oxidation, (1) the traditional follow-up of residual substrate by gas liquid chromatography, and (2) an analytical procedure by high-performance size-exclusion chromatography (HPSEC) for direct measurement of the oxidation compounds formed. The HPSEC method enabled us to quantitate oxidized monomers, dimers and polymers concomitantly in a rapid and direct analysis. Results showed that conjugated methyl linoleate samples oxidized later than their non-conjugated counterparts, and showed a very different oxidation pattern. Thus, formation of oxidized monomers was negligible and the first and major compounds formed were polymerization products. Also, under the conditions used, non-conjugated and conjugated methyl linoleate samples in 1:1 mixtures led to decreased oxidation rate of non-conjugated methyl linoleate and increased oxidation rate of conjugated methyl linoleate. This study supports the view that oxidation kinetics of conjugated dienes differ substantially from that of methylene-interrupted dienes.

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Section: Introductionmentioning

confidence: 99%

Differences in Oxidation Kinetics Between Conjugated and Non‐Conjugated Methyl Linoleate

Luna

Fuente

Salvador

et al. 2007

Lipids

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“…At first, the anticarcinogenic response was attributed to the antioxidant activity of CLA (1,2). However, further investigation showed that CLA functions as a prooxidant (9,10), and its effectiveness is different depending on its chemical form, i.e., as free fatty acids, methyl esters, or as a constituent in triacylglycerols or phospholipids (9)(10)(11).…”

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confidence: 99%

Effects of conjugated linoleic acid on oxygen diffusion‐concentration product and depletion in membranes by using electron spin resonance spin‐label oximetry

Yin

Mossoba

Kramer

et al. 1999

Lipids

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The effect of conjugated linoleic acid (CLA) on the relation between structure and function of membranes is described in this paper. Electron spin resonance (ESR) spin-label oximetry was used in the present study to evaluate if oxygen transport and oxygen depletion were affected by incorporation of CLA instead of linoleic acid into membrane phospholipids. Specifically, 1-stearoyl-2-(9cis, 11 trans-octadecadienoyl)-phosphorylcholine (SCLAPC) was incorporated into soy plant phosphatidylcholine (soy PC) or egg yolk PC (EYPC) bilayers. The use of spin labels attached to different carbons along the fatty acid chain makes it possible to carry out structural and oximetric determinations with the same test sample. For example, the incorporation of 5 mol% SCLAPC increased the oxygen diffusion-concentration product in soy PC or EYPC liposomes at 37 degrees C, slightly decreased the ordering of the hydrocarbon chains at the C10 and C12 positions (in the region of the conjugated double bonds), and increased the rate of oxygen depletion from the aqueous medium. Similar results were not obtained by incorporating 5 mol% of 1-stearoyl-2-linoleoyl-PC (SLPC). In our model system, free-radical generation was initiated by extended incubation of the liposomes, by induction by 2,2'-azobis(2-amidinopropane)hydrochloride, or by ultraviolet irradiation of H2O2. The rate of consumption of molecular oxygen was studied by monitoring the oxygen concentration in the aqueous phases of the liposomes. The effect of 5 mol% SCLAPC in soy PC was significantly larger than 5 mol% SLPC in soy PC; the response patterns with soy PC and EYPC were similar. Furthermore, 5 mol% SCLAPC in 1-palmitoyl-2-linoleoyl-PC showed similar oxygen consumption to that observed with 5 mol% SCLAPC in EYPC. On the other hand, 5 mol% SCLAPC in synthetic PC membranes containing saturated or monounsaturated fatty acids showed low oxygen depletion rates. The perturbation of membrane structure and the increase of the relative oxygen diffusion-concentration products provided a potential mechanism by which CLA incorporated into membrane lipids could affect oxidative stress.

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“…Nevertheless, the Non-TMR steaks had significantly higher proportion of 18:3n-3 and many of its BHI products (P < 0.01), some of which are known to be relatively unstable (ex. conjugated linoleic acid; Zhang and Chen, 1997). Hence, a detailed study of the relationship between individual fatty acids and the fishy off-flavor found in the Non-TMR steaks was undertaken.…”

Section: Resultsmentioning

confidence: 99%

Palatability of Beef from Cattle Fed Extruded Flaxseed before Hay or Mixed with Hay

Prieto

Dugan

Larsen

et al. 2017

Meat and Muscle Biology

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This study was undertaken to evaluate the eating quality of longissimus thoracis steaks and hamburgers (80/20 gluteus medius to perirenal fat) with enhanced profiles of potentially healthy fatty acids. The profile of health favorable fatty acids (n-3, vaccenic and rumenic) was improved in beef by feeding co-extruded flaxseed (flaxseed, peas, and alfalfa) and alfalfa-grass hay as a total mixed ration (TMR), and further enhanced by feeding co-extruded flaxseed before alfalfa-grass hay (Non-TMR). Compared to TMR, feeding steers the Non-TMR resulted in tougher steaks (P < 0.05) with lower beef flavor (P < 0.01) and greater off-flavor (P < 0.01) intensity to an extent that might be detectable by consumers. High levels of trans-monounsaturated fatty acids, mainly of vaccenic acid, were associated with a fishy off-flavor, although actual changes in flavor may relate to correlated combined effects of conjugated fatty acids, atypical dienoic acids and ɑ-linolenic acid. Diet had no significant effect on sensory attributes of hamburgers, but when panelists described off-flavors, they noted more ‘other’ off-flavors (P < 0.05) with fishy and stale/cardboard notes being more prominant in Non-TMR hamburgers. Overall, beef samples with threshold levels of vaccenic acid over 6.12% of total fatty acids resulting from feeding flaxseed products, while of potentially greater health benefit, may pose challenges in terms of eating quality. Areas worthy of further investigation to ensure acceptable eating quality might be the influence of ageing on antioxidant capacity in beef with enhanced fatty acid profiles, and the potential use of protective packaging to limit deterioration.

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Oxidative stability of conjugated linoleic acids relative to other polyunsaturated fatty acids

Cited by 76 publications

References 6 publications

Differences in Oxidation Kinetics Between Conjugated and Non‐Conjugated Methyl Linoleate

Differences in Oxidation Kinetics Between Conjugated and Non‐Conjugated Methyl Linoleate

Effects of conjugated linoleic acid on oxygen diffusion‐concentration product and depletion in membranes by using electron spin resonance spin‐label oximetry

Palatability of Beef from Cattle Fed Extruded Flaxseed before Hay or Mixed with Hay

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