Lipid oxidation inhibition

Products studies provide more direct evidence than the kinetic approach for the stoichiometry of lipid oxidation inhibited by phenolic antioxidants. Thus, n equals 2 with various phenolic compounds, because both the peroxide products (LOOA) of reaction (6) and the dimers (A-A) of reaction (7) were identified from tri-substituted phenols and from less hindered phenols containing more methyl than ferf-butyl substituents and from a-tocopherol (Figure 9.3). Reactions (6) and (7) are supported by product studies with various trialkylphenols varying in stability according to their substituents. 

JACOBSEN C, HARTVIGSEN K, THOMSEN M K, HANSEN L F, LUND P, SKIBSTED L H, H0LMER G, ADLER-NissEN J and MEYER A s (2001) Lipid oxidation in fish oil enriched mayonnaise calcimn disodium ethylenediaminetetraacetate, but not gallic acid, strongly inhibited oxidative deterioration, J Agric Food Chem, 49, 1009-19. 

Methylanaline could be transnitrosated with nitrite and S-nitrosocysteine and also by a simulated protein bound nitrite. In the latter case, an important factor was the local concentration of nitrosothiol groups on the matrix. The effects of S-nitrosocysteine as an inhibitor of lipid oxidation, as a color developer, and as an anticlostridial, have been reported recently in a turkey product (31). The Molar concentration of RSNO equating to 25 ppm nitrite gave similar results for color and inhibition of lipid oxidation but had less anti-clostridial activity. Transnitrosation between RSNO and heme protein was demonstrated. 

Probucol, another di-r-butyl phenol, is an anti-atherosclerotic agent that can suppress the oxidation of low-density lipoprotein (LDL) in addition to lowering cholesterol levels. The antioxidant activity of probucol was measured, using EPR, with oxidation of methyl linoleate that was encapsulated in liposomal membranes or dissolved in hexane. Probucol suppressed ffee-radical-mediated oxidation. Its antioxidant activity was 17-fold less than that of tocopherol. This difference was less in liposomes than in hexane solution. Probucol suppressed the oxidation of LDL as efficiently as tocopherol. This work implies that physical factors as well as chemical reactivity are important in determining overall lipid peroxidation inhibition activity (Gotoh et al., 1992). 

In the laboratory, apples have been found to have very strong antioxidant activity, inhibit cancer cell proliferation, decrease lipid oxidation, and lower cholesterol (Boyer... 

Sanchez-Moreno C, Larrauri JA and Saura-Calixto F. 1999b. Free radical scavenging capacity and inhibition of lipid oxidation of wines, grape juices and related polyphenolic constituents. Food Res Int 32(6) 407—412. 

O DormeU, V. B., Chumley, P. H., Hogg, N., Bloodsworth, A., Darley-Usmar, V. M., and Freeman, B. A., 1997, Nitric oxide inhibition of Upid peroxidation kinetics of reaction with lipid peroxyl radicals and comparison with alpha-tocopherol, Biochemistry 36 15216-15223. 

B Chronic hyperlipidemia and chronic infection potentiate inflammation and lipid oxidation. An increase of lipid oxidation might inhibit tbe immune system and thus facilitate a chronic infection and a rise in oxLDL-mediated apoptosis. 

Nobel and Wang reported that the permeability of the outer membranes of chloroplasts was increased by exposure to ozone (at 30 ppm for 5 min). They hypothesized that the effect was lipid oxidation. Freebaim showed that ozone inhibited respiratory activities of isolated mitochondria, and Lee found that the effect of ozone on oxidative phosphorylation was greater than on oxygen uptake. Mudd et reported that the metabolism of UDP-galactose by isolated... 

The oxidation hypothesis of atherosclerosis states that the oxidative modification of LDL (or other lipoproteins) is important and possibly obligatory in the pathogenesis of the atherosclerotic lesion thus, it has been suggested that inhibiting the oxidation of LDL will decrease or prevent atherosclerosis and clinical sequelae. LDL oxidation also has important implications for vascular health function. High concentrations of LDL may inhibit arterial function in terms of the release of nitric oxide from the endothelium and many of these effects are mediated by lipid oxidation products. Furthermore, oxidized LDL inhibits endothelium-dependent nitric oxide-mediated relaxations in isolated rabbit coronary arter-... 

Wang, L. L, Xiong, Y. L. (2005). Inhibition of lipid oxidation in cooled beef patties by hydrolyzed potato protein is related to its reducing and radical scavenging ability. J. Agric. Food Chem., 53, 9186-9192. 

Over the years, scientists have used many types of antioxidants in a variety of foods to retard or inhibit lipid oxidation and, thus, increase shelf-life and preserve quality. These antioxidants include free radical scavengers, chelators, and oxygen absorbers. While there are numerous antioxidants available to food scientists, the objective of this report was to discuss several of these antioxidants as they relate to meat flavor quality research and to show how they were used to retard lipid oxidation and prevent meat flavor deterioration in ground beef patties. 

Interest has been shown in using derivatives of ascorbic acid as antioxidants. One such compound is ascorbyl palmitate. In the structure of ascorbyl palmitate, the 2- and 3-positions are occupied by hydroxyl groups the 6-position contains the substituted fatty acid. Other derivatives, synthesized by Seib and associates were ascorbate-2 phosphate and ascorbate 2-triphosphate (27). Both of these compounds were reported to inhibit lipid oxidation in ground meat as measured by chemical means (2). Ascorbate-2-phosphate was also found to inhibit MFD in beef as measured by sensory means (2). The ascorbate-2-triphosphate was not tested as an inhibitor of MFD in this study, but... 

When the antioxidants were used in the cooked/stored samples, data indicated that they were very effective in inhibiting lipid oxidation and MFD. The chemical and off-flavor indicators were reduced and the on-flavor notes were increased. Thus, phenolic-type primary antioxidants that function as free radical scavengers are very effective tools for preventing lipid oxidation and MFD in ground beef. It should also be noted that the intensity of the desirable flavor notes remained at very high levels, which meant that the patties retained their beefy tastes. Therefore, for an antioxidant to be highly effective, it should not only prevent lipid oxidation, but it should also retain the desirable flavor properties of the food commodity. 

Broussochalcone A (32) Antioxidant activity (inhibition of lipid peroxidation) Inhibition of cyclooxygenase Inhibition of nitric oxide production Inhibition of respiratory burst in neutrophils Platelet aggregation inhibitory activity1 [42] [431 [42] [44] [431... 

Milk contains trace amounts of SOD which has been isolated and characterized it appears to be identical to the bovine erythrocyte enzyme. SOD inhibits lipid oxidation in model systems. The level of SOD in milk parallels that of XO (but at a lower level), suggesting that SOD may be excreted in milk in an attempt to offset the pro-oxidant effect of XO. However, the level of SOD in milk is probably insufficient to explain observed differences in the oxidative stability of milk. The possibility of using exogenous SOD to retard or inhibit lipid oxidation in dairy products has been considered. 

Derivatives of ubiquinones are antioxidants for foodstuffs and vitamins (qv) (217,218). Ubichromenol phosphates show antiinflammatory activity (219). Chromanol compounds inhibit oxidation of fats and can be used in treatment of macrocytic anemias (220). Monosulfate salts of 2,3-dimethoxy-5-methyl-6-substitutedhydroquinone have been reported to be inhibitors of lipid oxidation in rats (221). Polymers based on chloranilic and bromanilic acid have been prepared and contain oxygenated quinones (63), which are derived from 1,2,3,4-benzenetetrol (222). 

Probably far more important than the partitioning behavior is the fact that lipid oxidation in emulsions is site specific—i.e., most of the radicals are actually formed at or near the membrane. A close proximity to the interface is required to catalyze the reaction (Asua et al., 1989). Studies have shown that it is primarily the interfacial/subsurface concentration of transition metals that controls the rate of the reaction, while the concentration of transition metals in the bulk phase is secondary. This insight also provides a means to reduce the rate of the reaction. Experiments using a number of different antioxidants have in fact proven that lipid oxidation is most effectively inhibited if surface-active antioxidants are added. Antioxidants that are able to accumulate at the interface are closer to the site of lipid oxidation initiation and are therefore more efficient (Frankel et al., 1996). 

The inhibition of lipid (LH) oxidation may be considered as one of the most important chemical reaction mechanisms that could explain the antioxidant function of flavonoids. In general terms, chain-breaking antioxidants (AH) inhibit or retard lipid oxidation (reactions 1-7) by interfering with initiation [generically represented by reaction 1] or with chain propagating reactions (reactions 2 and 3) by readily donating hydrogen atoms to lipid peroxyl radicals (LOO ) or lipid radicals (L ) (reactions 4 and 5) [Frankel, 1998] ... 

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