Nonenzymic browning. IX. Correlation of autoxidation and browning reactions in lipid-protein mixtures

Pokorný, Jan; El-Zeany, B. A.; Kołakowska, Anna; Janícék, G.

doi:10.1007/bf01810486

Cited by 21 publications

(2 citation statements)

References 25 publications

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“…With water additives of 5.6 and 8.4%, a darker brown tone was observed at the end of storage. Similar color changes were already observed for different lipid‐protein mixtures in previous studies . Color changes were associated with the interaction of lipid oxidation products and proteins as well as polymerization or cross‐linking, cleavage reactions, increased hydrophobicity of proteins, and the formation of lipid‐protein complexes .…”

Section: Resultssupporting

confidence: 86%

Influence of Water Addition on Lipid Oxidation in Protein Oleogels

Meissner

Keppler

Stöckmann

et al. 2019

Euro J Lipid Sci & Tech

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The aim of the present study is the investigation of lipid oxidation in protein based oleogels. For this purpose, oleogels are prepared by suspension of freeze dried whey protein isolate aggregates and small amounts of water (<10%) in purified oleic rich safflower oil. The formation of conjugated dienes positively correlates with the addition of water. In contrast, a lower concentration of aldehydes is measured by headspace gas chromatography in oleogels with higher water addition, indicating a water facilitated degradation of aldehydes reacting with proteins. Determination of water activity indicates the presence of water droplets at higher water addition to oleogels. Furthermore, changes in the surface appearance (greasy‐glossy to dull) and the texture (consistent gel vs. crumbly) structure are indicative of microstructural changes due to increased water addition. The study suggests that water droplet formation is responsible for the marked increase in lipid oxidation. However, cross reaction of aldehydes with proteins is suggested to result in lowering the levels of secondary lipid oxidation products hexanal and propanal in oleogel. Practical Applications: The practical applications of the present work are related to the fabrication, processing, storage and consumption of oleogels and other protein‐lipid‐matrices. The results clearly indicate oleogels are prone to oxidation and proteins are involved by cross‐reaction resulting in visible browning during storage. Oxidation products such as hexanal (marker for secondary lipid oxidation) may not reflect the level of oxidation due to degradation by cross‐reactions with proteins. The aim of the present study is the investigation of lipid oxidation in protein based oleogels. The formation of conjugated dienes positively correlates with the addition of water. In contrast, a lower concentration of aldehydes is measured in oleogels with higher water addition. Water activity indicates the presence of water droplets at higher water addition to oleogels, which are likely responsible for the marked increase in lipid oxidation. However, cross reaction of aldehydes with proteins is suggested to result in lowering the levels of secondary lipid oxidation products hexanal and propanal in oleogels.

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Section: Resultssupporting

confidence: 86%

Influence of Water Addition on Lipid Oxidation in Protein Oleogels

Meissner

Keppler

Stöckmann

et al. 2019

Euro J Lipid Sci & Tech

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“…Lipid oxidation produces reactive oxygen groups and free radicals that attack proteins and amino acids in aqueous solutions or dispersions, anhydrous and low water systems, − and the frozen state and accelerate oxidation of proteins. These reactions decrease the nutritional quality of proteins due to browning, ,− insolubilization (increasing hydrophobicity of proteins), , loss of enzyme activity, ,, and loss of cellular membrane integrity in vivo. − Furthermore, the carbonyl groups of oxidized lipids may participate in covalent bonding to exposed amino groups of protein, leading to the formation of stable protein–lipid complexes. − Methionine, cysteine, tryptophan, lysine, histidine, and tyrosine residues in proteins were reported as the most sensitive amino acids to lipid oxidation products. Transient free radicals from lipid peroxidation may accelerate major protein-damaging reactions and the human aging process .…”

Section: Introductionmentioning

confidence: 99%

Oil as Reaction Medium for Glycation, Oxidation, Denaturation, and Aggregation of Whey Protein Systems of Low Water Activity

Potes

Kerry

Roos

2013

J. Agric. Food Chem.

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Whey protein isolate (WPI)-oil (75:25) and WPI-oil-(glucose-fructose) (45:15:40) as models of high-protein systems containing either olive (OO) or sunflower oil (SO) were stored at 20 or 40 °C to investigate component interactions. The indicators of protein oxidation (carbonyl content) and aggregation (total sulfhydryl content) and heats of protein denaturation and aggregation were investigated. Highest levels of disulfide bonding and carbonyls in WPI-OO formed during the first 2 weeks of storage concomitantly with enhanced protein aggregation. WPI-OO and WPI-SO systems (prestorage) showed increased protein denaturation temperature. The WPI proteins showed higher heat sensitivity with OO or SO at 40 °C, and the system with OO showed preaggregated protein as found from decreased heats of protein aggregation. OO or SO in WPI-oil-(glucose-fructose) systems reduced heats of protein aggregation. Lipid oxidation products and nonenzymatic browning reactions in glucose-fructose-containing systems decreased the solubility of solids and increased protein aggregation, hydrophobicity, and hardening of structure.

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Reaktionen oxydierter Lipide mit Eiweißstoffen. 9. Mitt. Bildung von Proteinoligomeren

El-Zeany¹,

Pokorný²,

Šmidrkalovä³

et al. 1975

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Gemische von polyungesättigten Fettsäureestern mit Eialbumin mit geringem Wassergehalt wurden bei 60°C aufbewahrt und die Veränderungen des Proteinanteils mittels Fraktionierung auf Sephadex‐G‐100‐Säulen bewertet. Der Gehalt an der wasserlöslichen Proteinfraktion nahm durch Denaturierung ab. Der Anteil an wasserlöslicher monomerer Fraktion sank ab, während der der dimeren und trimeren Fraktionen während der Lagerung anstieg. Die Oligomerisierung des Albumins wurde mit einer Abnahme von Thiolgruppen begleitet.

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Nonenzymic browning. IX. Correlation of autoxidation and browning reactions in lipid-protein mixtures

Cited by 21 publications

References 25 publications

Influence of Water Addition on Lipid Oxidation in Protein Oleogels

Influence of Water Addition on Lipid Oxidation in Protein Oleogels

Oil as Reaction Medium for Glycation, Oxidation, Denaturation, and Aggregation of Whey Protein Systems of Low Water Activity

Reaktionen oxydierter Lipide mit Eiweißstoffen. 9. Mitt. Bildung von Proteinoligomeren

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