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PubMed2004

Transbilayer distribution of aminophospholipids and the oxidative stability of their component polyunsaturated fatty acids.

We examined the relationship between the transbilayer distribution of aminophospholipids, such as phosphatidylethanolamine (PE), PE plasmalogen and phosphatidylserine, and the oxidative stability of polyunsaturated fatty acids (PUFAs) in the aminophospholipids. To modulate the transbilayer distribution of aminophospholipid in liposomes, we used phosphatidylcholine (PC) with two types of acyl chain region: dipalmitoyl (PC16:0) or dioleoyl (PC18:1). In the smaller-sized liposomes, the proportions of aminophospholipid in the liposomal external layer were significantly higher in liposomes containing PC18:1 than in those containing PC16:0. Additionally, aminophospholipids in the external layer of smaller-sized liposomes were able to protect their component PUFAs from 2,2'-azobis(2-amidinopropane)dihydrochloride-mediated lipid peroxidation.

Amines↗
PubMed1997

Tenderizing spent fowl meat with calcium chloride. 4. Improved oxidative stability and the effects of additional aging.

The goal of these experiments was to determine the effects of CaCl2 and NaCl injections on spent fowl meat tenderness and oxidative stability. Two hundred spent Leghorn hens were used in this two-part study. In the first experiment, breast fillets from 160 spent Leghorn hens were harvested immediately after death, injected with 0.3 M CaCl2 or H2O, vacuum tumbled, and either cooked immediately after tumbling or aged at 1 C for 23 h prior to cooking. Although the CaCl2 injection reduced shear values without aging, additional tenderization occurred during the aging period. In the second experiment, breast fillets from 40 spent Leghorn hens were harvested immediately after death, injected with 0.3 M CaCl2, 0.6 M NaCl, 0.15 M CaCl2 + 0.3 M NaCl, or H2O, vacuum tumbled, and then aged at 1 C for 23 h before cooking. The three salt injection treatments reduced shear values to a similar extent, but the sarcomeres were significantly longer for the NaCl treatment than the CaCl2 or combination treatments. Panelists preferred the CaCl2 + NaCl fillets over the CaCl2 fillets. Replacing some of the CaCl2 with NaCl maintained the tenderizing effect, and panelist comments indicated that the slight aftertaste of the 0.3 M CaCl2 treatment was reduced. The sodium contribution of the 0.6 M NaCl treatment would also be reduced by the CaCl2 + NaCl treatment.

Animals↗
PubMed2001

Effects of dietary supplementation with vitamin E and organic selenium on the oxidative stability of beef.

The effects of supplementation of beef cattle diets with organic Se (0.3 mg/kg) and vitamin E (300 I.U. alpha-tocopheryl acetate/kg feed), for 55 d preceding slaughter, on the antioxidant status and oxidative stability of muscle was examined. Dietary vitamin E supplementation led to an increase (P < 0.05) in plasma, and longissimus muscle alpha-tocopherol levels. In minced longissimus muscle stored in 80% 02:20% CO2, lipid and oxymyoglobin oxidation were lower (P < 0.05) in muscle from vitamin E-supplemented animals compared with unsupplemented animals. Dietary Se supplementation did not significantly affect muscle Se levels, glutathione peroxidase activity, or susceptibility to lipid and oxymyoglobin oxidation in the presence or absence of vitamin E. Covariance analysis indicated that, in addition to muscle alpha-tocopherol, differences in muscle glutathione peroxidase activity, and pH could account for variation in the susceptibility of muscle to lipid and oxymyoglobin oxidation.

Animal Feed↗
PubMed1999

Effect of beta-carotene and vitamin E on oxidative stability in leg meat of broilers fed different supplemental fats.

The objectives of this study were to investigate the effects of dietary fat (6% lard and sunflower and olive oil) and supplementation of alpha-tocopheryl acetate or beta-carotene on vitamin E content and lipid oxidation in raw, cooked, and chilled-stored broiler leg meat. Vitamin E increased its tissue level, reducing lipid oxidation. The oxidative stability of leg meat tended to decrease with dietary sunflower oil. Effects of beta-carotene on vitamin E levels and oxidation depended on dietary fat and its concentration in feed, decreasing vitamin E, mainly at 50 ppm. beta-Carotene at 15 ppm acted as antioxidant in fresh and cooked meat in the sunflower and olive oil diets. However, in stored meat, beta-carotene at 50 ppm increased TBARS, probably due to a decrease in vitamin E content and direct prooxidant effects per se. It is suggested that the antioxidant effect of beta-carotene requires the presence of vitamin E in tissues.

Animals↗
PubMed1996

Oxidative stability and alpha-tocopherol retention in turkey burgers during refrigerated and frozen storage as influenced by dietary alpha-tocopheryl acetate.

1. The effect of vitamin E (alpha-tocopheryl acetate) in turkey diets on the oxidative stability of raw and cooked turkey burgers and on the retention of alpha-tocopherol during refrigerated (4 degrees C) or frozen (-20 degrees C) storage was investigated. One hundred and two, one-day-old T-8s turkey poults were divided at random into 3 groups of 34 animals each and fed on either a basal diet (normal commercial turkey diet) supplemented with 20 mg alpha-tocopheryl acetate/kg (control) or fed an alpha-tocopherol supplemented diet containing 300 (E300) or 600 (E600) mg alpha-tocopheryl acetate/kg for 21 weeks. 2. Dietary supplementation with alpha-tocopheryl acetate significantly reduced TBARS numbers in both raw and cooked burgers during refrigerated and frozen storage. 3. The mean values of alpha-tocopherol in raw and cooked burgers stored at 4 degrees C did not change during storage. 4. In the case of both raw and cooked samples stored at -20 degrees C, the alpha-tocopherol values decreased from 5.67 to 3.54 and from 3.56 to 2.30 micrograms/g in the raw burgers from turkeys from the E600 and E300 treatments, respectively, after 4 months storage. The values decreased from 5.60 to 2.88 and from 3.29 to 1.85 micrograms/g in cooked burgers from turkeys from the E600 and E300 treatments, respectively, after 5 months storage.

Animals↗
PubMed2000

Oxidative stability of conjugated linoleic acid isomers.

Conjugated linoleic acids (CLAs) have been shown to be a strong anticarcinogen in a number of animal models. Our previous study demonstrated that CLA as a whole was extremely unstable in air. The present study was undertaken further to examine the oxidative stability of individual CLA isomers using the combination of gas-liquid chromatography (GLC) and silver ion high-performance liquid chromatography (Ag-HPLC). It was found that CLA as a whole oxidized rapidly and more than 80% was degraded within 110 h in air at 50 degrees C. Four c,c-CLA isomers were most unstable followed by four c,t-CLA isomers. In contrast, four t,t-CLA isomers were relatively stable under the same experimental conditions. Both the oxygen consumption and the GLC analysis revealed that 200 ppm jasmine green tea catechins (GTCs) exhibited protection to CLA and were even stronger than 200 ppm butylated hydroxytoluene (BHT) when added to either CLA or canola oil containing 10% CLA. The present study emphasized that oxidative unstability of CLA should not be overlooked although CLA has many biological effects.

Antioxidants↗
PubMed2004

Effect of dietary dried tomato pulp on oxidative stability of Japanese quail meat.

Ninety, 21-day-old, Japanese quail (Coturnix coturnix japonica) divided into three groups with five subgroups each were fed a basal diet that served as control or a basal diet containing 5 or 10% of dried tomato pulp (DTP), a byproduct of the tomato-processing industry. The DTP contained lycopene and beta-carotene at 281 and 24.3 mg kg(-)(1) of dry weight, respectively. On day 42 of age, birds were slaughtered, and carcasses were trimmed for breast meat. To assess the effect of dietary treatment on the oxidative stability of raw and cooked meat, raw meat was subjected to iron-induced lipid oxidation, whereas both raw and cooked meats were subjected to refrigerated storage at 4 degrees C. The extent of lipid oxidation was determined on the basis of the malondialdehyde (MDA) formed through the use of third-order derivative spectrophotometry. Results showed that after 6 and 9 days of refrigerated storage, MDA values in raw meat were increased. The increase was higher (P < 0.05) for the 10% DTP group and lower (P < 0.05) for the 5% DTP group, compared to control. An analogous oxidation profile was observed for cooked meat at 3, 6, and 9 days of storage. Iron-induced lipid oxidation of raw meat showed that the 10% DTP group as well as the control group exhibited MDA values that did not differ (P > 0.05) from each other at all time points, whereas the 5% DTP group presented MDA values that, although not differing from those of the other groups at 0 and 50 min, were significantly (P < 0.05) lower than those of the other groups at 100 and 150 min of iron-induced lipid oxidation. These results suggested that inclusion of dried tomato pulp in feed at a level of 5% exerted an antioxidant effect, whereas addition at level of 10% exerted a prooxidant effect. Mean alpha-tocopherol levels in the control, 5% DTP, and 10% DTP groups were 2.2, 2.1, and 1.4 mg kg(-)(1) of meat, respectively. Fatty acid analysis showed that the 10% DTP group had a higher (P < 0.05) content of total polyunsaturated fatty acids and a greater (P < 0.05) unsaturated/saturated fatty acid ratio compared to control. There might be an interaction between DTP and alpha-tocopherol that is of importance for the balance between pro- and antioxidative activities. Future experiments should be designed to explore the interaction between individual carotenoids and tocopherols in order to better elucidate their role in oxidative changes.

Animal Nutritional Physiological Phenomena↗
PubMed1999

Effect of olive ripeness on the oxidative stability of virgin olive oil extracted from the varieties picual and hojiblanca and on the different components involved.

The initial stability of virgin olive oil depends on various factors, among which are the variety and the degree of fruit ripeness. The former, which genetically determines the composition of the olive and its oil, also marks, to some extent, its stability. However, oil stability changes as the olive ripens, so it is obvious that the degree of ripeness is an important factor. The oils were obtained by the Abencor system. Acidity, peroxide index, UV absorption at 232 and 270 nm, sensory analysis, fatty acid composition, tocopherols, phenolic compounds, orthodiphenolic compounds, sterols, pigments, and oxidative stability were determined, and the results were analyzed statistically. During ripening there was a decrease in all of the parameters studied except linoleic acid, Delta-5-avenasterol, and oil content, which increased. Virgin oils showed very good correlation between stability and the concentrations of total phenols, o-diphenols, tocopherols, chlorophyll pigments and carotenoids, linoleic and linolenic acids, total sterols, beta-sitosterol, and Delta-5-avenasterol.

Carotenoids↗
PubMed2003

Determination of sterol and fatty acid compositions, oxidative stability, and nutritional value of six walnut (Juglans regia L.) cultivars grown in Portugal.

Six cultivars (Franquette, Marbot, Mayette, Mellanaise, Lara, and Parisienne) of walnuts (Juglans regia L.) were collected during the 2001 crop, from Bragança, Portugal. Chemical composition, including moisture, total oil content, crude protein, ash, carbohydrates, and nutritional value, was evaluated. Fat was the predominant component, ranging from 62.3 to 66.5%. Total oil was extracted and analyzed for fatty acids, sterols, oxidative stability, and peroxide value. Fatty acids and sterols were determined by gas-liquid chromatography coupled to a flame ionization detector. Eighteen fatty acids were quantified. Polyunsaturated fatty acids and, in particular, linoleic acid were predominant. Beta-Sitosterol, delta(5)-avenasterol, and campesterol were the major sterols found. Differences were observed among the studied cultivars, especially in peroxide values and in the sterol profile.

Carbohydrates↗
PubMed1998

Assessment of alpha-tocopheryl acetate supplementation, addition of salt and packaging on the oxidative stability of raw turkey meat.

1. One-day-old turkey poults (n = 14) were randomised into 2 groups (n = 7) and fed diets containing 20 (E20) and 600 (E600) mg all-rac-alpha-tocopheryl acetate/kg food for 21 weeks prior to slaughter. Two batches were formed from E20 meat (E20) and E20 plus 10 g salt/kg (E20S). Two similar batches were formed from E600 meat (E600) and E600 plus 10 g salt/kg (E600S). 2. The effects of alpha-tocopheryl acetate supplementation and salt addition on the oxidative stability of raw turkey patties was investigated during aerobic and vacuum-packaged refrigerated (4 degrees C) storage. 3. Dietary alpha-tocopheryl acetate supplementation reduced TBARS (thiobarbituric acid reacting substances) numbers for raw overwrapped and vacuum-packaged turkey leg and breast patties. 4. Dietary alpha-tocopheryl acetate had the greatest influence on TBARS numbers for raw overwrapped turkey leg patties. 5. The addition of 10 g salt/kg increased TBARS numbers for overwrapped and vacuum-packaged turkey leg and breast patties. 6. Vacuum-packaged patties remained more oxidatively stable than similarly treated overwrapped patties throughout the experimental period.

Analysis of Variance↗
PubMed2004

Role of continuous phase protein on the oxidative stability of fish oil-in-water emulsions.

Whey protein isolate (WPI), soy protein isolate (SPI), and sodium caseinate (CAS) can inhibit lipid oxidation when they produce a positive charge at the interface of emulsion droplets. However, when proteins are used to stabilize oil-in-water emulsions, only a fraction of them actually absorb to the emulsion droplets, with the rest remaining in the continuous phase. The impact of these continuous phase proteins on the oxidative stability of protein-stabilized emulsions is not well understood. WPI-stabilized menhaden oil-in-water emulsions were prepared by high-pressure homogenization. In some experiments WPI was removed from the continuous phase of the emulsions through repeated centrifugation and resuspension of the emulsion droplets (washed emulsion). Unwashed emulsions were more oxidatively stable than washed emulsions at pH 7.0, suggesting that continuous phase proteins were antioxidative. The oxidative stability of emulsions containing different kinds of protein in the continuous phase decreased in the order SPI > CAS > WPI, as determined by both hydroperoxide and headspace propanal formation. Iron-binding studies showed that the chelating ability of the proteins decreased in the order CAS > SPI > WPI. The free sulfhydryls of both WPI and SPI were involved in their antioxidant activity. This research shows that continuous phase proteins could be an effective means of protecting omega-3 fatty acids from oxidative deterioration.

Caseins↗
PubMed1994

[Effect of rapeseed in beef cattle feeding on fatty acid composition, vitamin E content and oxidative stability of body fat].

Four groups of five fattening bulls each consumed a concentrate--wheat straw-diet (2.5:1) supplemented with either 0, 7, 14 or 21% ground rape seed for 350 days. Rape seed contained 427 g crude fat (ether extract) and 127 mg vitamin E per kg dry matter. The supplementation with rapeseed increased the fat concentrations in the rations from 25 to 50, 75 and 100 g, and of vitamin E from 11 to 19, 26 and 34 mg per kg dry matter. All bulls were slaughtered with about 560 kg body weight. Fatty acid composition of depot fat and of the fat of musc. long. dorsi were determined by gas liquid chromatography. Vitamin E concentrations in blood, depot fat and muscle were determined by HPLC. Oxidative stability of depot fat was measured as induction time by means of rancimat-test. Rape seed supplementation decreased C16-fatty acids and increased C18-fatty acids in depot and muscle fat. Muscle fat contained significantly more mono and poly unsaturated fatty acids (40.2 and 7.4%) than depot fat (33.5 and 2.0%, respectively). Rape seed supplementation enhanced significantly the vitamin E-concentrations in all body samples. In depot fat vit. E increased from 4.5 to 7.3, 8.5 and 14.9 micrograms/g. Induction time increased from 10.9 to 18.5, 16.1 and 19.5 h, when 0, 7, 14 or 21% rapeseed were added.

Adipose Tissue↗
PubMed2005

Dietary conjugated linoleic acid reduces lipid peroxidation by increasing oxidative stability in rats.

The antioxidative effect of conjugated linoleic acid (CLA) was examined by determining lipid peroxidation and antioxidative enzyme activities. Male Sprague-Dawley rats were fed one of the experimental diets-normal diet, vitamin E-deficient control diet, 0.5% CLA vitamin E-deficient diet, or 1.5% CLA vitamin E-deficient diet for 5 wk. Hepatic thiobarbituric acid reactive substances (TBARS) were increased in the vitamin E-deficient control group, but they were was significantly lowered in the CLA groups. Similarly, hepatic glutathione peroxidase activity was increased in the vitamin E-deficient diet and reduced by CLA supplementation. In addition, CLA caused a significant decrease in superoxide dismutase activity while having no effect on catalase activity. Analyses of the fatty acid composition revealed that dietary CLA was incorporated into hepatic microsomal membrane dose-dependently. Compared to the vitamin E-deficient control, CLA resulted in significantly higher saturated and monounsaturated fatty acids (palmitic and oleic acids) while lowering levels of oxidation-susceptible polyunsaturated fatty acids (linoleic, linolenic, and arachidonic acids) in both plasma and hepatic membrane. The concentrations of plasma cholesterol and triacylglycerol (TG) were lower in the 1.5% CLA group than in other groups. These results suggest that dietary CLA has antiatherosclerotic and antioxidant activity by increasing oxidative stability in plasma and hepatic membrane in the vitamin E-deficient rats.

Alanine Transaminase↗
PubMed1999

Effects of roasting on pyrazine contents and oxidative stability of red pepper seed oil prior to its extraction.

Red pepper seeds were roasted with constant stirring for 6, 9, 10, and 12 min at 210 degrees C, and oils were extracted from the roasted red pepper seeds using an expeller. The iodine values and fatty acid compositions of red pepper seed oils did not change with roasting time. The fatty acid composition of the oil obtained from the red pepper seeds roasted for 6 min was 0.24% myristic acid, 13. 42% palmitic acid, 0.33% palmitoleic acid, 2.07% stearic acid, 10. 18% oleic acid, 73.89% linoleic acid, and 0.37% linolenic acid, showing a fatty acid composition similar to that of high-linoleate safflower oil. Thirteen alkylpyrazines were identified in the roasted red pepper seed oils: 2-methylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, 2-ethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-5-methylpyrazine, trimethylpyrazine, 2,6-diethylpyrazine, 2-ethyl-3,5-dimethylpyrazine, tetramethylpyrazine, 2, 3-diethyl-5-methylpyrazine, 2-isobutyl-3-methylpyrazine, and 3, 5-diethyl 2-methylpyrazine. The pyrazine content increased markedly as the roasting time increased, showing 2.63, 5.01, 8.48, and 13.10 mg of total pyrazine/100 g of oils from the red pepper seeds roasted for 6, 8, 10, and 12 min, respectively, at 210 degrees C. 2, 5-Dimethylpyrazine in the roasted red pepper seed oil seemed to be the component most responsible for the pleasant nutty aroma of the oils. The oxidative stabilities of oils increased greatly as the roasting time increased.

Capsicum↗
PubMed2005

Small-angle neutron scattering and theoretical investigation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) stabilized oil-in-water microemulsions.

The aim of this study is to determine the effects of oil solutes and alcohol cosolvents on the structure of oil-in-water microemulsions stabilized by poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers. The systems investigated involved the solubilization of 1,3,5-trimethylbenzene or 1,2-dichlorobenzene by P123 (EO(20)-PO(70)-EO(20)) pluronic surfactant micelles in water and water + ethanol solvents. The structures of these swollen micelles were determined by small-angle neutron scattering (SANS). A thermodynamic model was employed to interpret the characterization data. The results of the thermodynamic model for micellization agreed well with the SANS data from samples of micelles swollen by both oils. The model predicted the size of the micelles within 5% accuracy using only one fitting parameter, the micelle polydispersity. Ethanol had significantly different effects on the polymer micelles that contained solubilized oil compared to pure polymer micelles. For pure polymer micelles, the addition of ethanol increased the solubility of the polymer and, therefore, decreased the total volume fraction of micelles, while for polymer-oil aggregates, ethanol tended to have a positive effect on the volume fraction of micelles. SANS results showed that the greatest divergence from pure aqueous solvent results occurred at oil concentrations above the microemulsion stability limit.

Journal Article↗
PubMed1995

Influence of dietary vitamin E on the oxidative stability and quality of pig meat.

Oxidation of lipids is a major cause of deterioration in the quality of muscle foods and can directly affect many quality characteristics such as flavor, color, texture, nutritive value, and safety of the food. Lipid oxidation in muscle systems is initiated at the membrane level in the intracellular phospholipid fractions. In the processing of muscle foods, one of the most important questions concerns the methods used to delay the initiation of oxidation and loss of quality. Vitamin E is a major lipid-soluble antioxidant, and one of its primary functions is to maintain and protect biological membranes against lipid peroxidation. Dietary vitamin E supplementation above requirement levels is effective in reducing lipid oxidation. This review focuses on the antioxidant function of vitamin E and how supplementation of the diet of pigs with vitamin E influences the rate of lipid peroxidation, color, water-holding capacity, and cholesterol oxidation in pig meat.

Animals↗
PubMed2000

The importance of being r: greater oxidative stability of RNA compared with DNA.

The 2'-hydroxyl group of ribose imparts hydrolytic lability on RNA, which provides a mechanism for numerous biological functions. Recent evidence from chemical cleavage studies shows that this hydroxyl group also stabilizes the sugar moiety in RNA towards oxidation relative to DNA. Is this just because RNA needs to be distinguishable from DNA or does it have other evolutionary significance?

Animals↗