Aldehydes lipid oxidation product

Zhou, S. and Decker, E. A. (1999). Ability of amino acids, dipeptides, polyamines, and sulfhydryls to quench hexanal, a saturated aldehydic lipid oxidation product. ]. Agric. Food Chem. 47,1932-1936. 

Pyrroles are common products in the reaction of different lipid oxidation products with primary amino groups of amines, amino acid, and protein (Zamora et al., 2000). For example, when squid microsomes were oxidized with iron and ascorbate, TEARS increased simultaneously with the -value (yellowness) and pyrrole compounds, concomitantly with a decrease in free amines. Off-color formation in squid muscle could be due to the nonenzymatic browning reactions occurring between aldehydic lipid oxidation products and the amines on phospholipids head groups... 

FIGURE 9.2 Proposed model for the impact of physical location of aldehydic lipid oxidation products on their reactivity with phospholipids amines. Physical locations include (A) aqueous, (B) interfacial, and (C) lipid phase. (From Thanonkaew, A. et al., J. Agric. Food Chem., 54, 956, 2006a. With permission.)... 

Volatile compounds generated by model systems of zeln, corn amylopectin and corn oil extruded at barrel temepratures of 120°C and 165°C were analyzed by GC and GC/MS. The largest quantities of lipid oxidation products were detected in systems containing all three components. In each system, the quantity of 2,4-deca-dienal was low relative to the quantities of hexanal, heptanal and benzaldehyde. Identification of the Maillard reaction products, 2-methyl-3(or 6)-pentyl-pyrazine, 2-methyl-3(or 6)-hexylpyrazine and 2,5-di-methyl-3-pentylpyrazine, suggested that lipid-derived aldehydes might be involved in the formation of substituted pyrazines. 4-Methylthiazole was identified as a major decomposition product of thiamin when corn meal containing 0.5% thiamin was extruded at a final temperature of 180°C. 

Analogous electron transfers involving the carboxylic acid group of fatty acids (Reaction 4) or lipid oxidation products such as aldehydes (Reaction 5) (35) can also occur to form radicals that are potential initiators. Reaction 4 with free carboxylic acids has been demonstrated with cobalt and short-chain organic acids (29, 36, 37), so the potential exists for its occurrence with fatty acids. The aldehyde... 

The oxidation products of lipids include volatile aldehydes and acids. Therefore, lipids are one of the major sources of flavors in foods. For example, much of the desirable flavors of vegetables such as tomatoes, cucumbers, mushrooms, and peas (Ho and Chen, 1994) fresh fish (Hsieh and Kinsella, 1989), fish oil (Hu and Pan, 2000) and cooked shrimp (Kuo and Pan, 1991 Kuo et al., 1994), as well as many deep-fat fried foods such as French-fried potatoes (Salinas et al., 1994) and fried chicken (Shi and Ho, 1994), are contributed by lipid oxidation. LOX-catalyzed lipid oxidation produces secondary derivatives, e.g., tetradecatrienone, which is a key compound of shrimp (Kuo and Pan, 1991). The major difference between the flavors of chicken broth and beef broth is the abundance of 2,4-decadienal and y-dodeca-lactone in chicken broth (Shi and Ho, 1994). Both compounds are well-known lipid oxidation products. A total of 193 compounds has been reported in the flavor of chicken. Forty-one of them are lipid-derived aldehydes. 

The desirable flavor in many cheeses is created, in part, by lipid oxidation products, such as ketones and aldehydes. In lipids consisting of short-chain FA, both oxidation and lipolysis influence off-flavor. 

Maillard reactions between components of the fried food (sugars and amino acids) are responsible for the golden color of fried products. Lipid oxidation products also contribute to the main reactions. Reactive oxidation products include aldehydes, epoxides, hydroxyketones, and dicarbonylic compounds, which react with lysine, proline, and other amino acids. 

Low-density lipoproteins contain numerous other lipid oxidation products apart from aldehydes that can participate in pathological events leading to atherosclerosis, or to modulation of gene expression. Indeed, oxidized derivatives of the major components of LDL, i.e., cholesterol and cholesterol esters, are of interest in this respect because they are consistendy foimd in human atherosclerotic lesions. 

It is important to note that the modifications generated by those lipid oxidation products contribute nearly to the same extent to DNA damage than the direct oxidized bases (Winczura et al. 2012). These lipid peroxidation aldehydes-DNA adducts have been reported in vivo in rodent and human DNA, in a wide variety of organs and tissue. For most of them, they can be found at a basal state (Marnett 1999 Nair et al. 1999, 2007), but their concentration is increased in the case of oxidative stress due, for instance, to inflammatory processes (Nair et al. 2007), but also in the case of PUFA-rich diet (Fang et al. 2007). For etheno-adducts, most of the studies report the presence of unsubstituted adducts, making the identification of the reactant enal impossible. However, a substituted etheno-adduct specific to the lipid oxidation product 4-oxo-nonenal has been found in greater amounts in the small intestine of mice prone to intestinal cancer (Min mice) and overexpressing the enzyme COX-2 involved in inflammatory processes than in the small intestine of control mice (Williams et al. 2006). 

Both LC-MS and MS/MS have permitted greatly improved analyses of various lipid oxidation products in the form of the intact neutral and polar lipid molecules or their partial degradation products, which was not possible by chromatographic methods alone. Thus, the hydroperoxides, epoxides, hydroxides, isoprostanes, and the core aldehydes and acids generated during nonenzymatic peroxidation have been identified in plasma lipoproteins and atheroma samples and have provided a new basis for hypotheses about the origin and progression of vascular disease. 

Oxygenated acylglycerols. Lipid peroxidation in biological tissues attracts much attention because of its possible contribution to the functional modulation of biomembranes and lipoproteins. It is believed to be involved in free-radical-mediated damage, carcinogenesis and ageing processes. Research requires specific, sensitive and reproducible procedures to quantify the lipid hydroperoxides in each lipid class as primary products and the alcohols and aldehydes as secondary products of the peroxidation reaction. The identification and quantification of lipid oxidation products is therefore of great practical and theoretical interest and MS has assumed a major role in these analyses as a result of the development of mild ionization techniques. 

Methods to measure lipid oxidation have generally been unspecific and not sufficiently sensitive to measure flavor and low levels of oxidative deterioration of food lipids. Several specific complementary methods are needed to determine the contribution of lipid oxidation products formed at different stages of the multi-step process of oxidative deterioration in foods. Since polyunsaturated hydroperoxides decompose more readily at higher temperatures to form aldehydes causing rancidity, it is important to measure both aldehydes and hydroperoxides to monitor lipid oxidation. For the reliable prediction of shelf life of foods containing polyunsaturated lipids, it is essential to use more than one specific method to determine oxidation at different levels and to store samples at several temperatures, preferably between 40 and 60°C. 

Lipid oxidation products can interact with proteins and amino acids, and can affect the flavor deterioration and nutritive value of food proteins. Peroxyl radicals are very reactive with labile amino acids (tryptophane, histidine, cysteine, cystine, methionine, lysine and tyrosine), undergoing decarboxylation, decarbonylation and deamination. Methionine is oxidized to a sulfoxide combined cysteine is converted to cystine to form combined thiosulfinate (Figure 11.4). Aldehydes, dialdehydes and epoxides derived from the decomposition of hydroperoxides react with amines to produce imino Schiff bases (R-CH=N-R ). Schiff bases polymerize by aldol condensation producing dimers... 

HNE is a colorless liquid soluble in most organic solvents (e.g., alcohols, hexane, and chloroform). HNE is a cytotoxic and mutagenic lipid oxidation product, and, therefore, this aldehyde should be used with caution and handled appropriately to minimize exposure. 

Turkey breast rolls Plum extract Increase juiciness, control lipid oxidation production of aldehydes Lee Ahn, 2005... 

However, peroxidation can also occur in extracellular lipid transport proteins, such as low-density lipoprotein (LDL), that are protected from oxidation only by antioxidants present in the lipoprotein itself or the exttacellular environment of the artery wall. It appeats that these antioxidants are not always adequate to protect LDL from oxidation in vivo, and extensive lipid peroxidation can occur in the artery wall and contribute to the pathogenesis of atherosclerosis (Palinski et al., 1989 Ester-bauer et al., 1990, 1993 Yla-Herttuala et al., 1990 Salonen et al., 1992). Once initiation occurs the formation of the peroxyl radical results in a chain reaction, which, in effect, greatly amplifies the severity of the initial oxidative insult. In this situation it is likely that the peroxidation reaction can proceed unchecked resulting in the formation of toxic lipid decomposition products such as aldehydes and the F2 isoprostanes (Esterbauer et al., 1991 Morrow et al., 1990). In support of this hypothesis, cytotoxic aldehydes such as 4-... 

Oxidative stress Lipid oxidation Oxygen absorption Manometric, polarographic Diene conjugation HPLC, spectrophotometry (234 nm) Lipid hydroperoxides HPLC, GC-MS, chemiluminescence, spectrophotometry Iodine liberation Titration Thiocyanate Spectrophotometry (500 nm) Hydrocarbons GC Cytotoxic aldehydes LPO-586, HPLC, GC, GC-MS Hexanal and related end products Sensory, physicochemical, Cu(II) induction method, GC TBARS Spectrophotometry (532-535 nm), HPLC Rancimat Conductivity F2-iP GC/MS, HPLC/MS, immunoassays... 

Oxidative damage to membrane polyunsaturated fatty acids leads to the formation of numerous lipid peroxidation products, some of which can be measured as index of oxidative stress, including hydrocarbons, aldehydes, alcohols, ketones, and short carboxylic acids. 

Decomposition of the primary products of lipid oxidation generates a complex mixture including saturated and unsaturated aldehydes such as hexanal. Hexanal is the most commonly measured end product of lipid oxidation, and both sensory and physicochemical methods are used for its determination. Where other antioxidant activity tests may be nonspecific, physicochemical measurement of hexanal offers the advantage of analyzing a single, well-defined end product. 

The ALDs are a subset of the superfamily of medium-chain dehydrogenases/reductases (MDR). They are widely distributed, cytosolic, zinc-containing enzymes that utilize the pyridine nucleotide [NAD(P)+] as the catalytic cofactor to reversibly catalyze the oxidation of alcohols to aldehydes in a variety of substrates. Both endobiotic and xenobiotic alcohols can serve as substrates. Examples include (72) ethanol, retinol, other aliphatic alcohols, lipid peroxidation products, and hydroxysteroids (73). 

According to the Cd 18-90 AOCS ° official method, the ANV is 100 times the optical density measured in a 1 cm cell, at 350 nm, of a solution containing 1.00 g of oil in 100 ml of the test solution. The measured absorbance is due to Schiff bases (167) formed when p-anisidine (166) undergoes condensation reaction with carbonyl compounds, according to equation 55. The carbonyl compounds are secondary oxidation products of lipids, such as a, S-unsaturated aldehydes and ketones derived from the hydroperoxides (see Scheme 1 in Section n.A.2.c), and their presence points to advanced oxidation of the oil. 

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