scholarly journals Insights on keto-hydroperoxide formation from O2 addition to the beta-tetrahydrofuran radical

2020 ◽  
Author(s):  
Katherine S. Lockwood ◽  
Nicole J. Labbe
Keyword(s):  
Hydroperoxide Formation

scholarly journals Quantitative and Predictive Modelling of Lipid Oxidation in Mayonnaise

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 287
Author(s):  
Donny W. H. Merkx ◽  
Andries Swager ◽  
Ewoud J. J. van Velzen ◽  
John P. M. van Duynhoven ◽  
Marie Hennebelle
Keyword(s):  
Lipid Oxidation ◽  
Oxidative Stability ◽  
Shelf Life ◽  
Onset Time ◽  
Predictive Modelling ◽  
Oxidation Products ◽  
Food Emulsions ◽  
Hydroperoxide Formation ◽  
Life Tests ◽  
Volatile Aldehydes

Food emulsions with high amounts of unsaturated fats, such as mayonnaise, are prone to lipid oxidation. In the food industry, typically accelerated shelf life tests are applied to assess the oxidative stability of different formulations. Here, the appearance of aldehydes at the so-called onset time, typically weeks, is considered a measure for oxidative stability of food emulsions, such as mayonnaise. To enable earlier assessment of compromised shelf-life, a predictive model for volatile off-flavor generation is developed. The model is based on the formation kinetics of hydroperoxides, which are early oxidation products and precursors of volatile aldehydes, responsible for off-flavor. Under accelerated shelf-life conditions (50 °C), hydroperoxide (LOOH) concentration over time shows a sigmoidal curvature followed by an acceleration phase that occurs at a LOOH-concentration between 38–50 mmol/kg, here interpreted as a critical LOOH concentration (CCLOOH). We hypothesize that the time at which CCLOOH was reached is related to the onset of aldehyde generation and that the characterization of the LOOH-generation curvature could be based on reaction kinetics in the first days. These hypotheses are tested using semi-empirical models to describe the autocatalytic character of hydroperoxide formation in combination with the CCLOOH. The Foubert function is selected as best describing the LOOH-curvature and is hence used to accurately predict onset of aldehyde generation, in most cases within several days of shelf-life. Furthermore, we find that the defining parameters of this model could be used to recognize antioxidant mechanisms at play.

Swelling, reductive stress, and cell death during chemical hypoxia in hepatocytes

1989 ◽  
Vol 257 (2) ◽  
pp. C347-C354 ◽  
Author(s):  
G. J. Gores ◽  
C. E. Flarsheim ◽  
T. L. Dawson ◽  
A. L. Nieminen ◽  
B. Herman ◽  
...  
Keyword(s):  
Cell Injury ◽  
Rat Hepatocytes ◽  
Iodoacetic Acid ◽  
Cell Killing ◽  
Cell Swelling ◽  
Reductive Stress ◽  
Chemical Hypoxia ◽  
Hydroperoxide Formation ◽  
Bleb Formation ◽  
The Relationship

In rat hepatocytes, we examined the relationship between cell volume, bleb formation, and loss of cell viability during chemical hypoxia with KCN plus iodoacetic acid. In hypotonic media (150-200 mosmol/kgH2O), cells swelled to a greater extent during chemical hypoxia than in isotonic media, but rates of cell killing were identical. Sucrose (300 mM) added to isotonic media prevented early cell swelling but actually accelerated cell killing. In contrast, mannitol (300 mM) improved cell survival but did not prevent cell swelling. Bleb formation occurred regardless of buffer tonicity. The antioxidants desferrioxamine and cyanidanol but not superoxide dismutase +/- catalase delayed lethal cell injury. Cell killing was greater during aerobic compared with anaerobic chemical hypoxia. Hydroperoxide formation was measured using a dichlorofluorescin assay and was accelerated during aerobic but not anaerobic chemical hypoxia. The results indicate that cell swelling is not the driving force for bleb formation or lethal cell injury. We conclude that “reductive stress” caused by respiratory inhibition favors formation of toxic oxygen species and may contribute to lethal cell injury during intermittent or incomplete oxygen deprivation.

Spectroscopic Study of Photosensitized Oxidation of Polyisoprene

1977 ◽  
Vol 50 (4) ◽  
pp. 704-713 ◽  
Author(s):  
M. A. Golub ◽  
M. L. Rosenberg ◽  
R. V. Gemmer
Keyword(s):  
Zero Order ◽  
Double Bonds ◽  
Photosensitized Oxidation ◽  
The Third ◽  
Type Process ◽  
Zero Order Kinetics ◽  
Hydroperoxide Formation ◽  
Cis And Trans ◽  
In Cis ◽  
Suitable Measure

Abstract The microstructural changes which occur in cis- and trans-1,4-polyisoprenes and in squalene during photosensitized oxidation were investigated with the aid of infrared and proton and carbon-13 NMR spectroscopy. The singlet oxygenation of these isoprenic compounds resulted in allylic hydroperoxides with shifted double bonds, according to the expected “ene”-type process. In contrast to trans-1,4-polyisoprene and squalene, which displayed the three possible double bond shifts, cis-1,4-polyisoprene showed essentially two of the shifts (to di- and trisubstituted double bonds) and very little of the third (to exomethylene groups). A suitable measure of the extent of hydroperoxidation was afforded by the absorbance ratio, A3400/A1440≡A′. Similar correlations of A′ with oxygen uptake were obtained for the three isoprenic compounds, using chlorophyll or methylene blue as sensitizer. The use of rose bengal gave erratic results indicative of some autoxidation accompanying the hydroperoxide formation. The singlet oxygenation followed zero-order kinetics, the relative rates for cis- and trans-1,4-polyisoprenes being approximately 1.0:1.5.

Hydroperoxide Formation and Thermal Oxidation of Methyl tert-Butyl Ether Oxidation at Low Temperature

2019 ◽  
Vol 33 (12) ◽  
pp. 12894-12904 ◽  
Author(s):  
Qiang Zhang ◽  
Mieko Kumasaki ◽  
Xiongmin Liu ◽  
Fan Ren ◽  
Yosuke Nishiwaki ◽  
...  
Keyword(s):  
Low Temperature ◽  
Thermal Oxidation ◽  
Methyl Tert Butyl Ether ◽  
Butyl Ether ◽  
Tert Butyl ◽  
Hydroperoxide Formation

Chiral ethylene-bridged flavinium salts: the stereoselectivity of flavin-10a-hydroperoxide formation and the effect of substitution on the photochemical properties

2017 ◽  
Vol 28 (12) ◽  
pp. 1780-1791 ◽  
Author(s):  
Jiří Žurek ◽  
Eva Svobodová ◽  
Jiří Šturala ◽  
Hana Dvořáková ◽  
Jiří Svoboda ◽  
...  
Keyword(s):  
Hydroperoxide Formation ◽  
Photochemical Properties

Organic hydroperoxide formation in the acid-catalyzed heterogeneous oxidation of aliphatic alcohols with hydrogen peroxide

RSC Advances ◽  
2014 ◽  
Vol 4 (38) ◽  
pp. 19716-19724 ◽  
Author(s):  
Qifan Liu ◽  
Weigang Wang ◽  
Ze Liu ◽  
Tianhe Wang ◽  
Lingyan Wu ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Aliphatic Alcohols ◽  
Heterogeneous Oxidation ◽  
Organic Hydroperoxide ◽  
Hydroperoxide Formation ◽  
Acid Catalyzed

We present detailed mechanisms for the formation and degradation of organic hydroperoxide during the acid-catalyzed heterogeneous oxidation of aliphatic alcohols with hydrogen peroxide.

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