Effect of Skin Wine Pomace and Sulfite on Protein Oxidation in Beef Patties During High Oxygen Atmosphere Storage

Meat storage in high oxygen atmosphere has been reported to induce protein oxidation reactions decreasing meat quality. The incorporation of antioxidants has been proposed to reduce the extent of these reactions. In this study, the ability of red and white skin wine pomaces as well as sulfites to inhibit protein oxidation were tested in beef patties stored for up to 15 days at 4 °C in a high oxygen atmosphere (70 % O2 and 30 % CO2). SO2 (300 ppm) effectively protected against protein oxidation measured as radical formation by electron spin resonance (ESR) spectroscopy, as thiol loss by the DTNB assay and as myosin heavy chain (MHC) disulfide crosslinking by SDS-PAGE. Pomace from red wine production with a total phenol of 9.9 mg gallic acid equivalent/g protected against protein radical formation and against MHC crosslinking, but not against thiol loss by addition of 2.0 % (w/w) to the beef patties. Pomace from white wine production with a total phenol of 4.0 mg gallic acid equivalent/g only protected against MHC cross-linking. For both types of wine pomace, protein modifications not seen for sulfite addition were observed and were proposed to involve covalent phenol addition to proteins. Red wine pomace may be an alternative to sulfite as a meat additive for protection of beef patties against protein oxidation.Autonomous Government of Castilla y León through the research projects (BU268A11-2 and BU282U13) and the Danish Council for Independent Research |Technology and Production within the Danish Agency for Science Technology and Innovation for granting the project entitled: BAntioxidant mechanisms of natural phenolic compounds against protein cross-link formation in meat and meat systems^ (11-117033)

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Not AvailableThis study was designed to examine the cardioprotective effect of squalene against isoprenaline-induced myocardial infarction in male albino rats. Levels of diagnostic markers [troponin T, homocysteine], lipoproteins [apolipoprotein Al, apolipoprotein B, lipoprotein (a)] (in plasma), total cholesterol, lipid peroxides (in plasma and heart tissue), and endogenous non-enzymatic antioxidants [vitamin C and vitamin EJ (in heart tissue)] were determined. Supplementation of squalene at 2% level along with feed for 45 days significantly prevented the isoprenaline-induced elevation in the diagnostic markers in plasma of experimental group of rats. It exerted an antilipidemic action against isoprenaline-induced hypercholesterolemia by maintaining the levels of cholesterol and lipoprotein components at near normalcy. Squalene supplementation exhibited an antioxidant effect against isoprenaline-induced myocardial infarction by blocking the induction of lipid peroxidation. A tendency to prevent the isoprenaline induced reduction in the non-enzymatic antioxidants such as vitamin E and C was also observed. The results of the present study indicate that the cardioprotective effect of squalene might be ascribable to its antilipidemic, antioxidant and membrane stabilizing properties.Not Availabl

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Not AvailableWe studied the cardioprotective effect of squalene on isoprenaline-induced myocardial infarction in male albino rats with respect to changes in the levels of lipid components in plasma and heart tissue. Prior administration of 2% squalene in feed for 45 days significantly reduced the isoprenaline-induced elevation in the levels of cholesterol, triglycerides, and free fatty acids in plasma and heart tissue of rats following myocardial infarction. It exerted an antilipidemic effect by reducing the level of low-density lipoprotein cholesterol with a parallel rise in the level of high-density lipoprotein cholesterol in plasma of experimental rats. A tendency to prevent the isoprenaline-induced depletion of phospholipids in the myocardium of experimental rats was also observed. In the present study, the pretreatment with squalene significantly counteracted the isoprenaline-induced lipid peroxidation and maintained the rats at near normal status. The results of the present study indicate that the overall cardioprotective effect of squalene is probably related to an inhibition of lipid accumulation by its hypolipidemic properties and/or its antioxidant properties.Not Availabl

Antioxidant potential of water hyacinth (Eichornia crassipes): In vitro antioxidant activity and phenolic composition

Not AvailableThe aims of the present study were (a) to extract and quantify the main phenolic acids and tocopherols from the petiole, leaves, and flowers of Eichornia crassipes; (b) to evaluate the antioxidant capacity of the extracts in four in vitro systems (1,1-diphenyl-2-pycryl-hydrazyl [DPPH] radical scavenging ability, iron chelating activity, reducing power, and prevention of oxidation in a liposome model system); and (c) its effectiveness in retarding lipid peroxidation in fish oil by accelerated stability test. Significant differences were observed in total and individual phenolic contents and in the antioxidant activities of extracts from the various parts of E. crassipes. Out of the 11 phenolic acids analyzed, ethanolic extracts contained high amounts of gallic, protocatechuic, gentisic, and p-hydroxybenzoic acid, whereas, water extracts contained less amounts of a varied number of phenolic acids. Ethanolic extracts of flower, which contained the highest total phenolic content, were found to have high DPPH radical scavenging activity and reducing power. However, ethanolic extracts of leaf exerted a high Fe2+ chelating activity and also inhibited lipid peroxidation process both in liposomes and fish oil. Our results demonstrate that E. crassipes, an underutilized aquatic weed, could be a potential natural antioxidant source for food, feed, and pharmaceutical applications.Not Availabl

Antioxidative Effect of Seaweed Extracts in Chilled Storage of Minced Atlantic Mackerel (Scomber scombrus): Effect on Lipid and Protein Oxidation

In this study, antioxidant activity of absolute ethanol, 50 % ethanol and water extracts of two species of seaweeds namely, Fucus serratus and Polysiphonia fucoides were evaluated for their ability to retard lipid and protein oxidation in minced mackerel. Mackerel mince added with 0.5 g/kg of extracts was prepared. For comparison, BHT at 0.2 g/kg and a control with no added extracts were also prepared. The samples were stored at 5 °C for 8 days, and sampling was done at time 0, 1, 2, 4, 5 and 8 days. The 50 % ethanolic extracts of P. fucoides were found to be very effective in retarding lipid and protein oxidation, as it resulted in low levels of peroxide value, volatiles and carbonyl compounds and protected against the loss of α-tocopherol and tryptophan residues. In spite of the higher phenolic content, the absolute ethanol extracts of both species showed a pro-oxidative tendency in minced mackerel. Water extract with lowest phenolic content showed no antioxidant effect in minced mackerel. In conclusion, the 50 % ethanolic extracts of P. fucoides can be a potential source of natural antioxidants, as these extracts have antioxidant activities similar to synthetic antioxidants such as BHT. However, the extent of protection offered by these extracts against protein oxidation was not clear and further studies are needed to understand the nature of the interaction between proteins and these extracts