Covalent Modification of Emulsified β-Casein Resulting from Lipid Peroxidation

Leaver, J. D.; Law, Andrew J. R.; Brechany, Elizabeth Y.

doi:10.1006/jcis.1998.5944

Cited by 23 publications

(16 citation statements)

References 17 publications

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“…Considering the ratios between the values of IP 0 and W 0 (hour, Tables and ) for the control olive, sunflower, and soybean oils versus their O/W emulsions (1102.8 vs. 1368.5, 6.0 vs. 20.0, and 5.1 vs. 9.1, respectively), the oxidative stability of the triacylglycerols was considerably improved in the aqueous environment but of the same polyunsaturation‐based order obtained in the bulk oils. This was in contrast to the fact that the oxidation rates are generally higher for the bulk oils dispersed in aqueous phases, due essentially to the high‐shear stress and pro‐oxidant effect of the local temperature elevation and the oxygen incorporation imposed by the intense mechanical forces during emulsification process . However, emulsification is able to restrict the contact between the oil droplets and oxygen through positioning the supportive emulsifiers, like the soybean protein isolate used in the present study, into the interface.…”

Section: Resultsmentioning

confidence: 73%

Antioxidant Activity of Gallic Acid as Affected by an Extra Carboxyl Group than Pyrogallol in Various Oxidative Environments

Rafiee

Farhoosh

Sharif

2018

Eur. J. Lipid Sci. Technol.

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The antioxidant activity of gallic acid and pyrogallol is studied by the DPPH• scavenging assay and the extent of oxidation inhibition of the triacylglycerols of various unsaturated oils (olive, sunflower, and soybean) and their oil‐in‐water emulsions. The gallic acid molecules with an electron‐donating carboxylate anion are significantly stronger DPPH• scavengers than pyrogallol molecules (IC50 = 11.4 vs. 20.2 μM). Regarding the prevention of the triacylglycerols from oxidation, gallic acid is of higher activity than pyrogallol in the bulk oils (86.1–1244.3 vs. 73.4–331.6) but of lower activity in the O/W emulsions (13.0–74.9 vs. 17.4–207.9), depending on their different antioxidant behaviors arisen from the free radical chain mechanism of action as well as interfacial phenomena. Practical Applications: The present study clarifies the role of the carboxyl group in gallic acid antioxidant activity, antioxidant activity as a function of the free radical chain mechanism as well as interfacial phenomena, critical concentration of reverse lipid hydroperoxide micelles as affected by the antioxidant activity, and the effect of the degree of lipid unsaturation on the antioxidant activity of gallic acid and pyrogallol. Comparative antioxidant performance of gallic acid and pyrogallol to scavenge 1,1‐diphenyl‐ 2‐picrylhydrazyl radical (DPPH•) in a methanolic system and to inhibit peroxyl radical (LOO•) in triacylglycerols of olive, sunflower, and soybean oils and their oil‐in‐water (O/W) emulsions.

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Section: Resultsmentioning

confidence: 73%

Antioxidant Activity of Gallic Acid as Affected by an Extra Carboxyl Group than Pyrogallol in Various Oxidative Environments

Rafiee

Farhoosh

Sharif

2018

Eur. J. Lipid Sci. Technol.

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“…48 Mass spectroscopy analysis of BCN extracted from an oxidized emulsion revealed an increase of approximately 300 Da in the protein mass, which was attributed to the addition of unsaturated aldehydes arising from oil oxidation on BCN. 49 Ultimately, the favored oxidation of adsorbed proteins as compared to unadsorbed ones was clearly highlighted from the measurement of protein-bound carbonyls (Figure 7). Carbonylation is recognized as a major modification in oxidized proteins.…”

Section: ■ Discussionmentioning

confidence: 99%

Modifications of Interfacial Proteins in Oil-in-Water Emulsions Prior to and During Lipid Oxidation

Berton

Ropers

Guibert

et al. 2012

J. Agric. Food Chem.

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Lipid oxidation is a major cause for the degradation of biological systems and foods, but the intricate relationship between lipid oxidation and protein modifications in these complex multiphase systems remains unclear. The objective of this work was to have a spatial and temporal insight of the modifications undergone by the interfacial or the unadsorbed proteins in oil-in-water emulsions during lipid oxidation. Tryptophan fluorescence and oxygen uptake were monitored simultaneously during incubation in different conditions of protein-stabilized oil-in-water emulsions. Kinetic parameters demonstrated that protein modifications, highlighted by decrease of protein fluorescence, occurred as an early event in the sequence of the reactions. They concerned more specifically the proteins adsorbed at the oil/water interface. The reactions led in a latter stage to protein aggregation, carbonylation, and loss of protein solubility.

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“…Much of this work has been performed in relatively simple model systems using a variety of techniques (Dalgleish, 1996) and frequently, hydrocarbon oils, which are easy to purify by fractional distillation, have been used in place of the triglyceride oils used in the manufacture of processed foods. However, recent research indicates that the behaviour of proteins in emulsified triglyceride and hydrocarbon oils can be very different (Leaver et al, 1999a(Leaver et al, , 1999b. This is particularly true when the effects of heating and ageing are considered.…”

Section: Discussionmentioning

confidence: 99%

Chemical changes in β‐Lactoglobulin structure during ageing of protein‐stabilized emulsions

Leaver

Law

Brechany

et al. 1999

Int J of Food Sci Tech

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Commercial protein-stabilized emulsions are often stored for many months. Reversed phase high performance liquid chromatography (HPLC) analysis of protein displaced from ␤-lactoglobulin-stabilized oil-in-water emulsions by the competitive adsorption of Tween 20, showed that whereas the retention time of protein displaced from a tetradecane-water interface did not change greatly upon ageing, that of the protein displaced from a soya oil-water interface did. The changes in the retention time of the displaced protein were accompanied by an increase in the mass of the protein. When 2-mercaptoethanol was added prior to emulsification, the rate of modification was significantly slower than in its absence. Tryptic digests of the displaced, modified protein showed that the changes were specific. Analysis of volatile components present in the emulsions showed that emulsification induced the autoxidation of the polyunsaturated fatty acyl chains of the soya oil resulting in the time-dependent formation of low molecular weight compounds. 2-Mercaptoethanol inhibits the process probably by reacting with hydroperoxides and terminating the chain reaction. Aldehydes, particularly enals, are known to react with nucleophilic amino acid residues such as lysine via addition and/or condensation reactions, leading to the observed increase in the mass of the protein. Figure 5 Schematic showing the proposed mechanism of covalent modification of adsorbed protein in triglyceride oilwater emulsions.

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Covalent Modification of Emulsified β-Casein Resulting from Lipid Peroxidation

Cited by 23 publications

References 17 publications

Antioxidant Activity of Gallic Acid as Affected by an Extra Carboxyl Group than Pyrogallol in Various Oxidative Environments

Antioxidant Activity of Gallic Acid as Affected by an Extra Carboxyl Group than Pyrogallol in Various Oxidative Environments

Modifications of Interfacial Proteins in Oil-in-Water Emulsions Prior to and During Lipid Oxidation

Chemical changes in β‐Lactoglobulin structure during ageing of protein‐stabilized emulsions

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