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PubMed2002

Effect of dietary sorghum cultivars on the storage stability of broiler breast and thigh meat.

A total of 450 1-d-old male broiler chicks were fed a corn-soy-flax meal-based diet (control), two cultivars of sorghum--Ruby Red (low tannin content) and Valpo Red (high tannin content)--were used at 10% level. Birds were slaughtered at the end of 42-d feeding trial. Boneless, skinless breast and thigh muscles were separated and ground to make patties. Half of the breast and thigh meat patties were individually packaged in zipper bags, and 2-TBA-reactive substances (TBARS) and colors of the patties were determined after 0 and 7 d of storage at 4 C. The other half was cooked and vacuum-packaged. The vacuum-packaged patties were used to determine time-dependent volatile production and oxidative change during 12-h holding time before analyses. Thigh meat from broilers fed the Valpo Red cultivar produced lower TBARS than that from control at Day 0. The amounts of aldehydes and sulfur compounds of cooked breast meats were lower from chickens fed the Valpo Red cultivar than those fed the control or Ruby Red cultivar. Dietary Valpo Red cultivar improved the oxidative stability of breast meat 8 and 12 h after cooking. Dietary sorghum slightly improved the color a* stability of raw thigh meat patties. This result indicated that feeding sorghum to broilers could improve some measures of the storage stability of broiler meat, but sorghum with high tannin content was more effective than that with low tannin content.

Aldehydes↗

PubMed2001

Influence of extraction temperature on amounts and quality of rendered chicken fat recovered from ground or homogenized skin.

A study was undertaken to determine the influence of extraction process on recovery and quality of fat from chicken skin. In order to do so, 20-kg batches of skin were ground (9.5 mm plate) or homogenized in a colloidal mill (0.2-mm knife set), then heated to 50 or 80 C to rupture fat cells. The fat was recovered by centrifugation and was evaluated for composition, appearance, and stability. A maximum amount of fat (89.6% of the fat initially contained in skin) was recovered from homogenized skin heated to 80 C, whereas heating ground skin to 50 C yielded the lowest fat recovery (51.5% of skin fat content). In general, fat composition and appearance were little affected by extraction conditions, with the exception that the fat extracted from homogenized skin contained more (P < or = 0.001) unsaponifiable cell membrane constituents (0.17 to 0.20%), including antioxidant tocopherol fractions (10.3 microg/ml), than the fat extracted from ground skin (0.08% and 7.5 to 8.3 microg/ml, respectively). This difference likely contributed to the greater oxidative stability of the fat extracted from homogenized skin, which was observed in Schaal oven tests.

Animals↗

PubMed1979

Response of lactating cows to 300 mg of supplemental vitamin E daily.

Ten Holstein cows in mid-lactation which had been fed only stored feeds for several years were paired on milk production. One cow from each pair was assigned to either the control or group treated with supplemental vitamin E for a 12-wk experiment. All cows were fed 3 kg alfalfa-brome hay, corn silage ad libitum, and concentrate at 1 kg/3 kg milk produced daily. This ration provided about 500 mg of vitamin E (total tocopherols) daily. Five cows were fed an additional 300 mg vitamin E daily as D-alpha-tocopherol acetate in their concentrate mix. Feeding the supplemental vitamin E increased the vitamin E content of milk fat 15 to 20% from 18 microgram/g fat to over 21 microgram/g fat. However, this change in vitamin E content of milk was not sufficient to improve the oxidative stability of the milk. Blood characteristics indicative of vitamin E status generally were unaffected by vitamin E supplementation although red cell hemolysis, glutamic oxaloacetic transaminase, and lactate dehydrogenase of serum were lower in blood of supplemented cows.

Animal Feed↗

PubMed2004

Incorporation and stabilization of omega-3 fatty acids in surimi made from cod, Gadus morhua.

Surimi containing omega-3 fatty acids from algal oil was prepared by the addition of oil-in-water emulsions or bulk oil. Emulsion and bulk oil were added separately to surimi to provide approximately 500 mg of omega-3 fatty acids per serving of surimi (85 g). Addition of the emulsion had no effect on surimi gel strength, whereas bulk oil decreased gel strength an average of 31%. All surimi treatments containing algal oil increased in Hunter b values due to the presence of carotenoids in the oil. Among cryoprotectants, sodium tripolyphosphate was the major surimi additive responsible for retarding the formation of lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS). Lipid hydroperoxide and TBARS formation was lower in surimi containing bulk oil compared to surimi with emulsified oil. Both EDTA and lipid soluble antioxidants were able to decrease lipid oxidation in surimi fortified with omega-3 fatty acids. This suggests that surimi containing nutritionally beneficial omega-3 fatty acids could be developed with good oxidative stability and gel strength.

Animals↗

PubMed2003

The structure of a mutant enzyme of Coprinus cinereus peroxidase provides an understanding of its increased thermostability.

Seven amino-acid substitutions introduced into the 343 amino-acid-long sequence of Coprinus cinereus peroxidase (CiP) led to a mutant enzyme (TS-rCiP) which is more stable than the native enzyme at higher temperature, pH and hydrogen peroxide concentrations. It is therefore more suitable for industrial applications. A structure determination was conducted on a deglycosylated but still active form of TS-rCiP based on X-ray diffraction data to 2.05 A resolution measured on a crystal cooled to 100 K and refined to R = 0.202 and R(free) = 0.249. The increased stability of the TS-rCiP enzyme can be understood from the structural changes of the TS-rCiP structure revealed by a comparative analysis with other known CiP structures. One of the more significant changes caused by three of the substitutions, I49S, V53A and T121A, is the conversion of a hydrophobic pocket into a hydrophilic pocket with associated changes in the water structure and the hydrogen-bonding interactions. The E239G substitution, which gives rise to increased thermostability at high pH, creates changes in the water structure and in the orientation of a phenylalanine (Phe236) in its vicinity. The three substitutions M166F, M242 and Y242F introduced to increase the oxidative stability do not introduce any structural changes.

Chemical Phenomena↗

PubMed1990

Use of thionitrobenzoic acid to characterize the stability of nitric oxide in aqueous solutions and in porcine aortic endothelial cell suspensions.

Nitric oxide is an important vasodilator which can be biologically produced from leukocytes and endothelial cells. However, it is highly unstable, which is an obstacle to detection and quantitation. We have exploited the reactivity of nitric oxide with thiols to establish an assay based on oxidation of thionitrobenzoic acid (TNB). The oxidation of thionitrobenzoic acid and the reaction with oxygen, which was measured by employing an oxygen electrode, were examined after the addition of nitric oxide solutions. The inhibition of aggregation of human platelets after challenge with 2.5 microM adenosine diphosphate was also investigated. These studies show the following properties of nitric oxide in aqueous solutions. (i) Nitric oxide is highly reactive to oxygen. (ii) Thiols react with a labile, highly reactive nitric oxide-oxygen product. (iii) Medium with very low oxygen content increases the life span of nitric oxide in aqueous solution. We also used the nitric oxide quantitation using TNB to study the metabolism of nitric oxide by porcine aortic endothelial cells and the results show that nitric oxide added to these cells in low oxygen content solution is stable. From these studies, we conclude that deoxygenated solutions stabilize nitric oxide. An important consequence of low oxygen content at localized tissue sites may be to augment biological effects mediated by nitric oxide.

Animals↗

PubMed2002

Determinant parameters and components in the storage of virgin olive oil. Prediction of storage time beyond which the oil is no longer of "extra" quality.

This work studies the changes in the quality indices standardized by the European Union, together with the evolution of the oxidative stability and sterols, polyphenols, alpha-tocopherol, pigments, and fatty acids contents throughout the storage of Picual and Hojiblanca olive cultivar "extra" virgin olive oils at 2 degrees C + darkness and 30 degrees C + illumination. Only two quality indices (K(270) and sensory evaluation) indicate the loss of the extra quality of the oil during storage, and there is an excellent correlation between initial stability and the time to reach the limit of K(270) > 0.25 (after which the oil quality is no longer of "extra" quality). This time can be predicted with an error of <10%, which is of great commercial interest and previously unknown. Also unknown until now is that the changes in polyphenols, pigments, and alpha-tocopherol with storage time follow first-order kinetics.

European Union↗

PubMed2006

Effect of added caffeic acid and tyrosol on the fatty acid and volatile profiles of camellia oil following heating.

Camellia oil is widely used in some parts of the world partly because of its high oxidative stability. The effect of heating a refined camellia oil for 1 h at 120 degrees C or 2 h at 170 degrees C with exogenous antioxidant, namely, caffeic acid and tyrosol, was studied. Parameters used to assess the effect of heating were peroxide and K values, volatile formation, and fatty acid profile. Of these, volatile formation was the most sensitive index of change as seen in the number of volatiles and the total area count of volatiles in gas chromatograms. Hexanal was generally the dominant volatile in treated and untreated samples with a concentration of 2.13 and 5.34 mg kg(-1) in untreated oils heated at 120 and 170 degrees C, respectively. The hexanal content was significantly reduced in heated oils to which tyrosol and/or caffeic acid had been added. Using volatile formation as an index of oxidation, tyrosol was the more effective antioxidant of these compounds. This is contradictory to generally accepted antioxidant structure-activity relationships. Changes in fatty acid profiles after heating for up to 24 h at 180 degrees C were not significant.

Aldehydes↗

PubMed2000

The protective role of different green tea extracts after oxidative damage is related to their catechin composition.

The antioxidant activities of three different green tea extracts were investigated and compared by two different methods. By the first method, which evaluated the direct protective effect of the green tea extracts on lipid peroxidation, the extracts were added, at different concentrations, to a lipid model system, made by refined peanut oil, freshly submitted to a further bleaching and subjected to forced oxidation at 98 degrees C, by an oxidative stability instrument. By the second method, the effectiveness of the same extracts was checked in cultures of neonatal rat cardiomyocytes exposed to a free radical-generating system by evaluating conjugated diene production and lactate dehydrogenase release. All of the extracts revealed a strong antioxidant activity by both the methods, and a particular effectiveness was demonstrated by the extracts having higher amounts of (-)-epigallocathechin-3-gallate and (-)-epigallocathechin, as analyzed by reverse-phase HPLC analysis.

Animals↗

PubMed2005

Hunting oxygen complexes of nitric oxide synthase at low temperature and high pressure.

The reaction of nitric oxide synthase (NOS) with oxygen is fast and takes place within several steps, separated by ephemeral intermediates. The use of extreme experimental conditions, such as low temperature and high pressure, associated to rapid kinetic analysis, has proven to be a convenient tool to study this complex reaction. Stopped-flow experiments under high pressure indicated that oxygen binding occurred in more than one step. This was further corroborated by the detection of two short-lived oxy-compounds, differing in their spectral and electronic properties. Oxy-I resembles the ferrous oxygen complex known for cytochrome P450, whereas oxy-II appears to be locked in the superoxide form. Subzero temperature spectroscopy, together with an analytical separation method, revealed that the subsequent one-electron reduction of the oxygen complex is carried out by the NOS cofactor tetrahydrobiopterin (BH4). The low-temperature stabilized oxidation product of BH4 was found to be a protonated BH3 radical. Finally, work in the presence of a BH4 analog indicated that proton transfer to the activated oxygen complex is a second essential function of BH4.

Animals↗

PubMed2005

Characterization of irradiated blends of alpha-tocopherol and UHMWPE.

Adhesive/abrasive wear in ultra-high molecular weight polyethylene (UHMWPE) has been minimized by radiation cross-linking. Irradiation is followed by melting to eliminate residual free radicals and avoid long-term oxidative embrittlement. However, post-irradiation melting reduces the crystallinity of the polymer and hence its strength and fatigue resistance. We proposed an alternative to post-irradiation melting to be the incorporation of the antioxidant alpha-tocopherol into UHMWPE prior to consolidation. alpha-Tocopherol is known to react with oxygen and oxidized lipids, stabilizing them against further oxidative degradation reactions. We blended GUR 1050 UHMWPE resin powder with alpha-tocopherol at 0.1 and 0.3 wt% and consolidated these blends. Then we gamma-irradiated these blends to 100-kGy. We characterized the effect of alpha-tocopherol on the cross-linking efficiency, oxidative stability, wear behavior and mechanical properties of the blends. (I) The cross-link density of virgin, 0.1 and 0.3 wt% alpha-tocopherol blended, 100-kGy irradiated UHMWPEs were 175+/-19, 146+/-4 and 93+/-4 mol/m3, respectively. (II) Maximum oxidation indices for 100-kGy irradiated UHMWPE previously blended with 0, 0.1 and 0.3 wt% alpha-tocopherol that were subjected to accelerated aging at 80 degrees C in air for 5 weeks were 3.32, 0.09, and 0.05, respectively. (III) The pin-on-disc wear rates of 100-kGy irradiated UHMWPE previously blended with 0.1 and 0.3 wt% alpha-tocopherol that were subjected to accelerated aging at 80 degrees C in air for 5 weeks were 2.10+/-0.17 and 5.01+/-0.76 mg/million cycles, respectively. (IV) Both accelerated aged, alpha-tocopherol-blended 100-kGy irradiated UHMWPEs showed higher ultimate tensile strength, higher yield strength, and lower elastic modulus when compared to 100-kGy irradiated, virgin UHMWPE. These results showed that alpha-tocopherol-blended 100-kGy irradiated UHMWPEs were not cross-linked to the same extent as the 100-kGy irradiated, virgin UHMWPE.

Aging↗

PubMed1994

Consumption of thermally-oxidized sunflower oil by chicks reduces alpha-tocopherol status and increases susceptibility of tissues to lipid oxidation.

The effect of heated sunflower oil consumption on alpha-tocopherol status, fatty acid composition and oxidative stability of chicken tissues was investigated. Chicks were fed on diets containing (g/kg): fresh sunflower oil (FSO) 40, heated sunflower oil (HSO) 40 or heated sunflower oil (40) supplemented with alpha-tocopheryl acetate (HSE) to a similar alpha-tocopherol concentration as the FSO diet. Concentrations of alpha-tocopherol in tissues of chicks fed on HSO and HSE were significantly lower than those of chicks fed on FSO. Significant correlations were observed between plasma alpha-tocopherol concentration and the alpha-tocopherol concentrations of other tissues (r > or = 0.67, P < 0.005) and between log plasma alpha-tocopherol and plasma thiobarbituric acid-reacting substances (TBARS) concentrations (r -0.851, P < 0.001). The concentrations of TBARS in tissues of chicks fed on the various diets were generally very similar before stimulation of peroxidation with Fe-ascorbate. Susceptibility of tissues to Fe-ascorbate-induced lipid peroxidation was increased by feeding HSO. Supplementation with alpha-tocopheryl acetate reduced susceptibility to lipid oxidation to varying degrees, depending on the tissue. The results suggest that chronic ingestion of oxidized lipids may compromise free-radical-scavenging activity in vivo by depleting alpha-tocopherol in the gastrointestinal tract, or possibly in plasma and other tissues.

Animals↗

PubMed2002

Determination of the methionine requirement of male and female broiler chicks using an indirect amino acid oxidation method.

The methionine requirement of 250-to-300-g broiler chicks was estimated from the oxidation of L-[1-14C] phenylalanine of chicks given meals containing graded levels of DL-methionine. L-[1-14C] phenylalanine was used as an indicator amino acid for amino acid oxidation and, indirectly, protein synthesis. Four experiments were conducted using an incomplete block design with three replications each. Chicks were crop intubated with semifluid diets at a ratio of 1 g of diet per 45 g of bird weight. Two feedings 2 h apart were used to reduce variability, and the sample collection period was 3 h after the second feeding. Regression analysis of 14CO2 release from L-[1-14C] phenylalanine was used to estimate the methionine requirement. The model was as follows: response = max + rc x (req - x) x I, where max = plateau, rc = rate constant, req = requirement, and I = 1 when x < req, otherwise I = 0. The methionine requirements of Ross x Ross chicks were 0.57 +/- 0.03% and 0.52 +/- 0.08% for male and female chicks, respectively in Experiment 1 and 0.55 +/- 0.05% and 0.52 +/- 0.04%, respectively, in Experiment 2. In the third experiment (Arbor Acre High-Yield), phenylalanine oxidation stabilized at a low rate when dietary methionine levels reached 0.54 +/- 0.03% and 0.53 +/- 0.04% for males and females, respectively. In a growth trial covering a longer period (Experiment 4), the methionine requirements of male and female Ross x Ross chicks, based on feed conversion, were 0.52 +/- 0.05% and 0.45 +/- 0.02%, respectively, and based on body gain were 0.54 +/0.09% and 0.48 +/- 0.04%, respectively. The results suggested that the methionine requirement of male chicks tended to be higher than that of females in both strains. However, differences were small and not significant.

Animals↗

PubMed2001

Development of procedures for determining the amino acid requirements of chickens by the indicator amino acid oxidation method.

To better understand the amino acid requirements of chickens, a method is needed to determine a point estimate of the requirement. A method developed to determine the amino acid requirements of piglets and human infants by using the oxidation rate of an indicator amino acid as the test parameter was adapted for use in growing chickens. Polycarbonate chambers measuring 30 x 40 x 30 (L x W x H) were constructed to house one small mature chicken or several small immature chickens and to trap exhaled CO2. In the first experiment, 10-d-old chicks (250 to 300 g each) were feed deprived for 12 h and given 1 g of a methionine-deficient diet (gavage) with L-[1-C14]phenylalanine. Peak oxidation of L-[1-C14]phenylalanine occurred between 30 and 90 min (-200 dpm/g). A linear rate of oxidation (slope = -1.84; r2 = 0.96) was achieved by 120 min after feeding until after 180 min, when oxidation stabilized at a low rate. The second experiment tested different chambers and chicks with the same treatment to show repeatability. There were four chicks (250 to 300 g each) in each of three apparently identical chambers. Chicks were given two meals labeled with L-[1-C14]phenylalanine, 2 h apart. The CV for the 0- and 30-min collections were 17 and 10%, respectively. The CV for the remaining collections remained at <4%. These data supported a system of two feedings, 2 h apart to reduce variability and a collection period that included up to 3 h after the second feeding.

Amino Acids↗

PubMed2002

High-oleic and high-stearic cottonseed oils: nutritionally improved cooking oils developed using gene silencing.

Gene technology and plant breeding are combining to provide powerful means for modifying the composition of oilseeds to improve their nutritional value and provide the functional properties required for various food oil applications. Major alterations in the proportions of individual fatty acids have been achieved in a range of oilseeds using conventional selection, induced mutation and, more recently, post-transcriptional gene silencing (PTGS). In particular, a number of high-oleic oils have been developed in order to provide high-stability cooking oils. These oils provide the opportunity to replace the current widespread use of saturated fats and hydrogenated oils that contribute significantly to increased risk of cardiovascular disease due to the effect of saturated and trans-fatty acids on elevating LDL cholesterol in the bloodstream. Similarly, oils with increased stearic acid content are being developed to enable the production of solid fats without the need for hydrogenation. We have recently applied hpRNA-mediated PTGS in cotton to down-regulate key fatty acid desaturase genes and develop nutritionally-improved high-oleic (HO) and high-stearic (HS) cottonseed oils (CSOs). Silencing of the ghFAD2-1 delta12-desaturase gene raised oleic acid content from 13% to 78% and silencing of the ghSAD-1 delta9-desaturase gene substantially increased stearic acid from the normal level of 2% to as high as 40%. Additionally, palmitic acid was significantly lowered from 26% to 15% in both HO and HS lines. Intercrossing the HS and HO lines resulted in a wide range of unique intermediate combinations of palmitic, stearic, oleic and linoleic contents. The oxidative stability, flavor characteristics and physical properties of these novel CSOs are currently being evaluated by food technologists.

Cottonseed Oil↗

PubMed2004

Antimicrobial and antioxidant activities of natural extracts in vitro and in ground beef.

Inhibition of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes by grape seed extract (ActiVin) and pine bark extract (Pycnogenol) and the effect of these natural extracts on the oxidative stability of raw ground beef were studied. In an agar dilution test, the MICs of ActiVin and Pycnogenol were determined to be 4.0 mg/ml for 4.43 log CFU per plate of E. coli O157:H7 and 4.0 mg/ml for 4.38 log CFU per plate of L. monocytogenes. In an inhibition curve test, populations of E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes fell to below the detection limit (10 CFU/ml) after 16 h of incubation. The numbers of E. coli O157:H7, L. monocytogenes, and Salmonella Typhimurium declined by 1.08, 1.24, and 1.33 log CFU/g, respectively, in raw ground beef treated with 1% Pycnogenol after 9 days of refrigerated storage. ActiVin (1%) and oleoresin rosemary (1%) resulted in an approximately 1-log CFU/g reduction in the populations of all three pathogens after 9 days. The addition of 1% ActiVin and Pycnogenol contributed to the maintenance of an acidic pH of 5.80 and 5.58, respectively, in raw ground beef. Compared to the control, all treatments increased in L* (lightness), with the exception of ActiVin. ActiVin and oleoresin rosemary had the highest a* (redness) and b* (yellowness) values, respectively. ActiVin most effectively retarded lipid oxidation, followed by Pycnogenol. The results suggest that these natural extracts have potential to be used with other preservative methods to reduce pathogenic numbers, lipid oxidation, and color degradation in ground beef.

Animals↗

PubMed1996

Palatability of sous vide processed chicken breast.

The influences of brine composition, internal temperature, heating rate, and storage periods up to 28 d on flavor, texture, and color of sous vide processed chicken breast were evaluated. Pectoralis major muscles containing water and sodium chloride, with or without sodium lactate, were browned and vacuum packaged. Sous vide processing was by fast or slow heating to an internal temperature of 77 or 94 C. Product was evaluated after 0, 14, and 28 d storage at 4 C. Quality was evaluated by gas chromatographic analyses of flavor volatiles, shear, color, and sensory panels. Incorporation of sodium lactate into brine did not influence oxidative stability (as measured by headspace gas chromatography) or sensory warmed-over flavor. Presence of sodium lactate did result in enhanced fresh roasted or meaty and saltiness sensory scores as well as a more yellow color. The more rapid heating rate decreased sulfur-containing compounds and did not influence other volatile concentrations. Products processed to 94 C were less juicy, less tender, and contained higher quantities of alcohols and hydrocarbons than those processed to 77 C. Storage resulted in a decline in fresh roasted or meaty flavor note and an increase in warmed-over flavor note and quantities of alcohols, aldehydes and ketones, hydrocarbons, and total headspace volatiles.

Aldehydes↗

PubMed2003

Docosahexaenoic acid-containing phosphatidylethanolamine in the external layer of liposomes protects docosahexaenoic acid from 2,2'-azobis(2-aminopropane)dihydrochloride-mediated lipid peroxidation.

We have proposed that incorporation of docosahexaenoic acid (DHA) into phosphatidylethanolamine (PE) might enhance resistance to lipid peroxidation in vivo. In this study, we examined the relationship between the transbilayer distribution of PE and the oxidative stability of DHA in PE. Liposomes composed of a phospholipid mixture were used as models for biological membranes. To modulate the transbilayer distribution of PE obtained from the liver of rats fed DHA (PE-DHA), we used phosphatidylcholine (PC) with two types of acyl chain region: dipalmitoyl (PC16:0) or dioleoyl (PC18:1). The proportion of PE-DHA in the liposomal external layer was significantly higher in liposomes containing PC18:1 than in those containing PC16:0. This tendency was more pronounced in liposomes extruded using a polycarbonate filter with smaller pore sizes. Additionally, PE-DHA in the external layer of liposomes prepared using a filter with smaller pore sizes could protect DHA itself from 2,2(')-azobis(2-aminopropane)dihydrochloride-mediated lipid peroxidation.

Amidines↗