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Biomedical subjects

M Du

Publications and source records attributed to M Du.

At least 19 recordsLinked to original sources
PubMed2007

The halothane gene, energy metabolism, adenosine monophosphate-activated protein kinase, and glycolysis in postmortem pig longissimus dorsi muscle.

The presence of the halothane gene results in PSE meat. However, the exact mechanisms linking the halothane gene and the incidence of PSE meat remain unclear. We hypothesize that the presence of the halothane gene accelerates energy consumption in postmortem muscle, which activates adenosine monophosphate-activated protein kinase (AMPK), leading to enhanced glycolysis and PSE meat. To test our hypothesis, energy status, AMPK activity, and glycolysis in the postmortem LM of the halothane gene carrier and halothane-negative pigs were compared. The results showed that the presence of the halothane gene accelerated energy depletion in postmortem muscle immediately after exsanguination, leading to rapid and early depletion of ATP, as shown by an increase in the (adenosine monophosphate + inosine monophosphate):ATP ratio in postmortem LM. In addition, an early AMPK activation was observed in LM from halothane carriers. The fructose-2,6-diphosphate concentration in postmortem LM was well correlated with AMPK activation. To be a potent stimulator of phosphofructose kinase, the increase in fructose-2,6-diphosphate is expected to activate phosphofructose kinase, a key enzyme controlling glycolysis, leading to enhanced glycolysis and early accumulation of lactic acid. In summary, this study showed that the presence of the halothane gene induced early energy depletion, which could be a primary reason causing AMPK activation, leading to accelerated glycolysis and an increased incidence of PSE meat. However, AMPK might also be activated by other mechanisms besides energy depletion, which warrants further studies.

AMP-Activated Protein Kinases↗
PubMed2006

Leucine stimulates mammalian target of rapamycin signaling in C2C12 myoblasts in part through inhibition of adenosine monophosphate-activated protein kinase.

Mammalian target of rapamycin (mTOR) signaling is one of the main signaling pathways controlling protein synthesis. Leucine treatment upregulates mTOR signaling, which enhances protein synthesis; however, the mechanisms are not well understood. Herein, treatment of C2C12 myoblast cells with leucine enhanced the phosphorylation of mTOR and ribosomal protein S6 kinase. Leucine treatment also decreased the adenosine monophosphate/ATP ratio in myoblasts by 36.4 +/- 9.1% (P < 0.05) and reduced the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) alpha subunit at Thr172 (28.6 +/- 4.9% reduction, P < 0.05) and inhibited AMPK activity (43.6 +/- 3.5% reduction, P < 0.05). In addition, leucine increased the phosphorylation of mTOR at Ser2448 by 63.5 +/- 10.0% (P < 0.05) and protein synthesis by 30.6 +/- 6.1% (P < 0.05). Applying 5-aminoimidazole-4-carbox-amide 1-beta-d-ribonucleoside, an activator of AMPK, abolished the stimulation of mTOR signaling by leucine, showing that AMPK negatively controls mTOR signaling. To further show the role of AMPK in mTOR signaling, myoblasts expressing a dominant negative AMPKalpha subunit were employed. Negative myoblasts had very low AMPK activity. The activation of mTOR induced by leucine in these cells was abated, showing that AMPK contributed to mTOR activation. In conclusion, leucine stimulates mTOR signaling in part through AMPK inhibition. This study implicates AMPK as an important target for nutritional management to enhance mTOR signaling and protein synthesis in muscle cells, thereby increasing muscle growth.

AMP-Activated Protein Kinases↗
PubMed2006

Maternal nutrient restriction upregulates growth signaling pathways in the cotyledonary artery of cow placentomes.

This study evaluated the role of MAPK/ERK1/2 and/or PI3-K/Akt signaling pathways in modulating bovine placentomal vascularity in response to maternal nutrient restriction. Beef cows were randomly assigned to control fed (Control, n=15, 100% of requirements) or nutrient restricted (NR, n=15, 50% requirements) diets from day 30 to day 125 of gestation. Ten cows from each dietary group were necropsied on day 125 (approximately 45% gestation), and the remaining cows in each diet group were then fed control diets and necropsied on day 250 (approximately 90% gestation). At day 125 of gestation, NR cows exhibited increased (P=0.06) COT vascularity, improved (P<0.05) placentome efficiency (fetal weight/placentomal weight), and increased (P<0.05) phosphorylated Akt and ERK1/2 in COT arteries compared to Control cows. By day 250, however, treatment differences in COT vascularity and phosphorylated Akt and ERK1/2 in COT arteries were lost. On both gestational days, no treatment difference was observed in the levels of phosphorylated Akt or ERK1/2 in CAR arteries. CAR vascularity was similar across treatment on day 125, but tended to be greater (P<0.10) in NR than Control cows on day 250. These data suggest that conceptuses react to an early gestational nutrient restriction by up-regulating COT growth signaling pathways associated with angiogenesis, and that these compensations do not persist to term.

Animal Nutritional Physiological Phenomena↗
PubMed2006

Cardiac contractile dysfunction in Lep/Lep obesity is accompanied by NADPH oxidase activation, oxidative modification of sarco(endo)plasmic reticulum Ca2+-ATPase and myosin heavy chain isozyme switch.

AIMS/HYPOTHESIS: Obesity is an independent risk factor for heart diseases but the underlying mechanism is not clear. This study examined cardiac contraction, oxidative stress, oxidative modification of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) and the myosin heavy chain (MHC) isoform switch in obese mice. METHODS: Mechanical properties were evaluated in ventricular myocytes from C57BL/6J lean and Lep/Lep obese mice (formerly known as ob/ob mice), including peak shortening (PS), time to 50 or 90% PS, time to 50 or 90% relengthening (TR50, TR90), maximal velocity of shortening/relengthening (+/-dL/dt), intracellular Ca2+ and its decay (tau). Oxidative stress, lipid peroxidation, protein damage and SERCA activity were assessed by glutathione/glutathione disulfide, malondialdehyde, protein carbonyl and 45Ca2+ uptake, respectively. NADPH oxidase was determined by immunoblotting. RESULTS: Myocytes from Lep/Lep mice displayed depressed PS and +/- dL/dt, prolonged TR50, TR90, elevated resting [Ca2+]i, prolonged tau, reduced contractile capacity at high stimulus frequencies and diminished responsiveness to extracellular Ca2+ compared with lean controls. Cardiac glutathione/glutathione disulfide was decreased whereas malondialdehyde, protein carbonyl, membrane p47(phox) and membrane gp91(phox) were increased in the Lep/Lep group. SERCA isoenzyme 2a was markedly modified by oxidation in Lep/Lep hearts and associated with decreased 45Ca2+ uptake. The MHC isozyme displayed a shift from the alpha to the beta isoform in Lep/Lep hearts. Short-term incubation of angiotensin II with myocytes mimicked the mechanical defects, SERCA oxidation and 45Ca2+ uptake seen in Lep/Lep myocytes. Incubation of the NADPH oxidase inhibitor apocynin with Lep/Lep myocytes alleviated contractile defects without reversing SERCA oxidation or activity. CONCLUSIONS/INTERPRETATION: These data indicate that obesity-related cardiac defects may be related to NADPH oxidase activation, oxidative damage to SERCA and the MHC isozyme switch.

Animals↗
PubMed2006

Acetylenic TACE inhibitors. Part 3: Thiomorpholine sulfonamide hydroxamates.

A series of thiomorpholine sulfonamide hydroxamate TACE inhibitors, all bearing propargylic ether P1' groups, was explored. In particular, compound 5h has excellent in vitro potency against isolated TACE enzyme and in cells, oral activity in a model of TNF-alpha production and a collagen-induced arthritis model, was selected as a clinical candidate for the treatment of RA.

ADAM Proteins↗
PubMed2005

Impact of antimicrobial ingredients and irradiation on the survival of Listeria monocytogenes and the quality of ready-to-eat turkey ham.

Irradiation is an effective technology in eliminating Listeria monocytogenes, but it induces quality changes in meat products at or above specific radiation doses. To minimize irradiation-induced quality changes, only low irradiation doses are recommended. However, low-dose irradiation provides a chance for some pathogens to survive and proliferate during prolonged storage. To solve this problem, antimicrobial ingredients [2% sodium lactate (SL), 0.1% sodium diacetate (SDA), 0.1% potassium benzoate (PB)] and low-dose irradiation were combined and tested for their effects on the growth of L. monocytogenes and meat quality. The log10 reductions of L. monocytogenes in hams following exposure to 1.0 to 2.5 kGy of irradiation ranged from 2.0 to 5.0. The D10 values were 0.52 kGy for control ham or ham with PB, SL, or PB + SL; 0.49 kGy for ham with SL+SDA; and 0.48 kGy for ham with PB + SL + SDA (PSS). Addition of SL + SDA or PB + SL in combination with 1.0 kGy of irradiation was effective in suppressing the growth of L. monocytogenes for about 6 wk when stored at 4 degrees C, whereas 2.0 kGy of irradiation was listeriostatic. Ham irradiated with 1 kGy in combination with PSS was listeriostatic throughout storage. SL increased firmness of turkey hams, and sensory panelists noted that the saltiness was a little higher in products containing SL, but its overall impact on quality was minimal. Amounts of benzene were detected in irradiated hams with PB, showing PB was not fit as an antimicrobial ingredient for irradiated foods. In conclusion, 2% SL and 0.1% SDA in combination with low-dose irradiation were effective in ensuring the safety of ready-to-eat meat products against L. monocytogenes.

Animals↗
PubMed2005

Nutrient restriction differentially modulates the mammalian target of rapamycin signaling and the ubiquitin-proteasome system in skeletal muscle of cows and their fetuses.

The mammalian target of rapamycin (mTOR) signaling controls nutrient-stimulated protein synthesis in skeletal muscle, whereas ubiquitin-proteasome systems control the degradation of myofibrillar proteins. The objective of this study was to elucidate the effect of nutrient restriction on the mTOR signaling and ubiquitin-proteasome system in the skeletal muscle of cows and their fetuses. Beginning 30 d after conception, 20 cows were fed either a control diet that provided 100% nutrient requirements or a nutrient-restricted diet at 68.1% of NE(m) and 86.7% of metabolizable protein requirement. Cows were slaughtered on 125 d of gestation, and the LM of both cows and fetuses was sampled for the measurement of mTOR, ribosomal protein S6, adenosine 5'-monophosphate-activated protein kinase (AMPK), and protein ubiquitylation. When comparing the muscle samples from nutrient-restricted and control cows and their fetuses, no difference was observed for the content of mTOR and ribosomal protein S6, but the phosphorylation of mTOR at Ser(2448) and ribosomal protein S6 at Ser(235/336) were greater (P < 0.05) in control muscle than in muscle from nutrient-restricted animals. Because the phosphorylation of mTOR and ribosomal protein S6 upregulates translation, these results showed that nutrient restriction inhibits protein synthesis in muscle. The activity of AMPK in the muscle of nutrient-restricted cows was significantly lower (P = 0.05) than that of control cows. The protein ubiquitylation, however, was greater (P < 0.05) in the muscle from nutrient-restricted cows, showing accelerated protein degradation. No difference in the protein ubiquitylation was detected for fetal muscle. Data suggested that the decreased protein synthesis and promoted protein degradation resulted in muscle atrophy of pregnant cows, but not in fetal muscle. Results of this study show that in response to nutrient restriction, protein degradation was differentially regulated between cow and fetal muscle. The atrophy of cow muscle during nutrient deficiency may involve the enhanced degradation of muscle proteins.

AMP-Activated Protein Kinases↗
PubMed2005

Effect of dietary alpha-lipoic acid on growth, body composition, muscle pH, and AMP-activated protein kinase phosphorylation in mice.

The effects of alpha-lipoic acid (ALA) on the growth, body composition, postmortem AMP-activated protein kinase (AMPK) activation, and 24-h muscle pH were investigated. Thirty male C57BL/6J mice were fed diets containing 0, 0.5, or 1.0% ALA (DM basis). At the end of the 3-wk feeding trial, carcass weights decreased (P < 0.05) 14 and 30% for mice fed 0.5 and 1.0% ALA, respectively, compared with the 0% group, with decreases in BW as the levels of dietary ALA increased. This change in carcass weight occurred because carcass fat content for mice receiving 0.5 and 1.0% ALA was 7.32 and 8.09% lower (P < 0.05), respectively, than for the 0% ALA treatment, and because gonadal fat decreased (P < 0.05) 85% in mice fed 1.0% ALA compared with those fed 0% ALA. Dietary ALA caused a slight increase (P < 0.05) in carcass moisture content, with no (P = 0.07) effect on protein and ash content. Furthermore, ALA supplement decreased (P < 0.05) ADFI (DM basis) from 4.3 g/d for 0% ALA-fed mice to 3.4 g/d for 1.0% ALA-fed mice. At 20 min postmortem, pH was greater (P < 0.05) in muscle of mice fed 1.0% ALA than in muscle of mice fed 0% ALA. Ultimate (24-h) pH values differed (P < 0.05) among treatments, and mean values were 5.83, 6.08, and 6.29 for 0, 0.5, and 1.0% ALA, respectively. Phosphorylation of AMPK alpha subunit at Thr172, an indicator of AMPK activation, was decreased (P < 0.05) in muscle of ALA-treated mice at 20 min postmortem. Because AMPK has a crucial role in the control of glycolysis, the reduction in AMPK activation decreases glycolysis, and thereby increases the ultimate pH of postmortem muscle. In summary, dietary ALA supplement can decrease fat accumulation in mice, and because ALA increased muscle pH at 20 min and 24 h postmortem, these results suggest that dietary ALA supplementation might decrease carcass fatness and prevent the development of PSE pork and poultry. However, further research is required to test the effects of ALA in swine and poultry.

AMP-Activated Protein Kinases↗
PubMed2005

Multiple reaction monitoring as a method for identifying protein posttranslational modifications.

The activity of many transcriptional regulators is significantly altered by posttranslational modifications of specific sites. For example, the activity of the muscle-restricted transcription factor family myocyte enhancer factor 2 (MEF2) is tightly controlled by phosphorylation. This modification is responsible for either an increase or a decrease in transcriptional activity, depending on the specific amino acid residues that are phosphorylated by signal-dependent kinases. Although mass spectrometry-based methods, such as precursor ion and neutral loss scans, are extremely useful for identifying unknown phosphopeptides from a complex mixture, they do not take advantage of any prior knowledge about the protein being investigated. Quite often a significant amount of information is available. This may include the primary sequence, type of phosphorylation (serine/threonine vs. tyrosine), or predicted phosphoacceptor sites (consensus peptide that is targeted by a kinase). This information can be used to predict precursor and fragment ion m/z values for a multiple reaction monitoring (MRM) experiment. By using these highly sensitive MRM experiments to trigger dependent product ion scans on a hybrid quadrupole linear ion-trap instrument, we were able to identify low levels of phosphorylation of MEF2A (a member of the MEF2 family), and alpha-casein. This method of monitoring protein phosphorylation at specific phosphoacceptor sites may prove useful in understanding the physiological regulation of protein function.

Amino Acid Sequence↗
PubMed2004

Frequency and quantity of the parvovirus B19 genome in endomyocardial biopsies from patients with suspected myocarditis or idiopathic left ventricular dysfunction.

Parvovirus B19 (PB19) has been identified as a possible cause of myocarditis and heart failure in both children and adult patients. This study used real time PCR analysis, to determine the frequency and to quantify PB19 viral genomes in endomyocardial tissue samples from 80 adult patients with clinically suspected myocarditis or idiopathic left ventricular dysfunction and from 36 controls. Histological (Dallas classification) and immunohistological analyses were performed to detect myocardial inflammation in the endomyocardial biopsies.PB19 genomic DNA was found in nine of 80 patients (11.2%), 4 out of 31 (12.9%) patients with inflammatory infiltrates detected via immunohistological methods and 5 out of 49 (10.2%) patients with left ventricular dysfunction without myocardial inflammation. The copy numbers for PB19 DNA ranged between 30 and 3900 per microg of cellular DNA. Four patients with clinically suspected myocarditis had copy numbers for PB19 DNA of 70, 740, 3400 and 3900, respectively, per microg of cellular DNA in the endomyocardial biopsy. Five patients with idiopathic left ventricular dysfunction had copy numbers for PB19 DNA of 30, 38, 52, 58 and 90, respectively, per microg of cellular DNA in the endomyocardial biopsy. The amplicon of one of the nine positive PCR fragment was sequenced and was found to be fully identical in the highly conserved sequence of published Parvovirus B19 VP1/VP2 genes (NCBI gene bank). In all patients, acute myocarditis was excluded according to the Dallas classification. All biopsies of 36 controls with no history of myocarditis or recent viral infection were negative for myocardial inflammation and parvovirus B19 genomes. In summary, Parvovirus B19 DNA is present within the myocardium of patients with suspected myocarditis and idiopathic left ventricular dysfunction and can be detected and quantified in endomyocardial specimens via real time PCR.

Adult↗
PubMed2004

Effect of nutrient restriction on calpain and calpastatin content of skeletal muscle from cows and fetuses.

Calpains are crucial for the degradation of myofibrillar proteins in muscle. Calpastatin is a specific inhibitor of calpains. The objective of this study was to elucidate the effect of nutrient restriction on the activity of calpains and calpastatin in the skeletal muscle of both cows and fetuses. Beginning 30 d after conception, 20 cows were fed either a control diet consisting of native grass hay fortified with vitamins and minerals at recommendations for a mature cow to gain 0.72 kg/d or half the vitamins and minerals and millet straw at 68.1% of NEm requirements. Cows were slaughtered on d 125 of gestation, and the LM was sampled at the 12th rib for calpain and calpastatin measurement. When comparing the muscle samples from nutrient-restricted and control cows, no difference in the activity of calpain I and II was observed; however, there was a significant difference (P < 0.05) in calpastatin activity. Muscle samples from control cows had greater calpastatin content than those of nutrient-restricted cows (P < 0.05); in contrast, the calpastatin content of fetal muscle was greater in fetuses gestated by nutrient-restricted cows than those of control cows (P < 0.05). Further, there were three calpastatin isoforms of 125, 110, and 70 kD detected in fetal muscle, whereas only the110-kD isoform was detected for cow muscle. These results indicate that the activity of the calpain system in skeletal muscle is mainly controlled through the expression of calpastatin. Alternating the calpastatin content in muscle and thereby modulating calpain activity may provide a mechanism for the maintenance of fetal muscle growth during nutrient restriction, whereas skeletal muscle loss in cows is upregulated.

Animal Feed↗
PubMed2003

Dietary CLA affects lipid metabolism in broiler chicks.

A total of 120 three-wk-old broiler chicks were randomly assigned to three diets containing 0, 2, or 3% CLA and fed for 5 wk. Fat content and FA composition of liver, plasma, and feces were analyzed. Key enzymes involved in FA synthesis and catabolism in liver, TG, cholesterol, and FFA content of plasma were also determined. Dietary CLA increased TG, total cholesterol, and HDL cholesterol levels in plasma. The increased plasma TG level could be caused by increased FA synthesis in the liver after CLA feeding, because the activity of FA synthase in the liver increased after dietary CLA treatment. Dietary CLA changed the FA composition of feces but had no effect on fat content. Compared to the amounts of linoleic and linolenic acids present in the control diet, the amounts excreted into the feces of CLA-treated birds were significantly higher. Liver weights of broilers significantly increased after CLA feeding, but there was no difference in liver fat content among the different CLA treatments. CLA treatment did not influence total FFA content in plasma; however, there was a significant difference in the composition of FFA. Dietary CLA reduced the content of linoleic and arachidonic acids in both plasma and liver.

Acetyl-CoA Carboxylase↗
PubMed2003

Astragaloside IV and polysaccharide production by hairy roots of Astragalus membranaceus in bioreactors.

Hairy roots of Astragalus membranaceus were grown in bioreactors up to 30 l for 20 d. Cultures from a 30 l airlift bioreactor gave 11.5 g l dry wt with 1.4 mg g(-1) astragaloside IV, similar to cultures from 250 ml and 1 l flasks, but greater than yields from a 10 l bioreactor (dry wt 9.4 g l(-1), astragaloside IV 0.9 mg g(-1)). Polysaccharide yields were similar amongst the different bioreactors (range 25-32 mg g(-1)). The active constituent content of the cells approached that of plant extracts, indicating that large scale hairy root cultures of A. membranaceus has the potential to provide an alternative to plant crops without compromising yield or pharmacological potential.

Astragalus propinquus↗
PubMed2002

Off-odor volatiles and pink color development in precooked, irradiated turkey breast during frozen storage.

The effect of irradiation on color, lipid oxidation, and volatile production of precooked, irradiated turkey breast during frozen storage was studied. Turkey breast muscles were precooked, aerobically or vacuum-packaged, irradiated at 0, 2.5, or 5.0 kGy using a linear accelerator (electron beam), and then frozen-stored at -40 C. Lipid oxidation, volatiles, color values, gas production, and oxidation-reduction potential (ORP) of meat were determined during 3-mo storage periods. Ionizing radiation produced characteristic off-odor volatiles (dimethyldisulfide and methylthioethane) and lipid oxidation products in precooked, frozen turkey breast. The production of volatiles was accelerated by the confounding effect of high irradiation dose, aerobic packaging, and increased storage time. Volatile production and color changes in irradiated, precooked turkey breast were induced by different mechanisms. Irradiation increased pink color in precooked, vacuum-packaged turkey breast, and the pink color was stable during frozen storage. Decreased ORP and increased CO in irradiated meat indicated that denatured CO-heme pigments could be responsible for the pink color in precooked, irradiated turkey breast. Vacuum packaging was better than aerobic packaging in preventing lipid oxidation and oxidation-dependent volatile production, but pink color in precooked, irradiated turkey breast during frozen storage was maintained.

Animals↗
PubMed2002

Effect of dietary conjugated linoleic acid on the growth rate of live birds and on the abdominal fat content and quality of broiler meat.

Two experiments were conducted to investigate the influence of dietary conjugated linoleic acid (CLA) on the growth, body composition, abdominal fat accumulation, and meat quality in broilers. In Experiment 1, 50 broilers that were 3 wk old (total of 200 birds) were assigned to one of the four diets containing 0, 0.25, 0.5, or 1% CLA and were fed for 3 wk. In Experiment 2, 40 broilers that were 3 wk old (total of 120 birds) were assigned to one of the three diets containing 0, 2, or 3% CLA and fed for 5 wk. At the end of the 3-wk feeding trial, the average body weight of broilers for Experiment 1 was about 2.20 kg per bird for all treatments. For Experiment 2, after 5-wk feeding trial, the average body weights of birds were 4.04, 3.99, and 3.93 kg for the control, 2% CLA, and 3% CLA groups, respectively, with a non significant reduction in body weight as the levels of dietary CLA increased. There was no difference in abdominal fat weight, the total body fat, and protein content in broilers among the CLA treatments for Experiment 1. However, when the dietary CLA was increased to 2 or 3%, the total body fat content was reduced. The whole body fat content decreased from 14.2% in the control to 11.9 and 12.2% for 2 and 3% CLA, respectively. Dietary CLA at 2 and 3% levels influenced meat quality. After cooking, the breast meat from 2 or 3% dietary CLA treatment was harder and drier, and the color was a little darker than that of the control. These changes could be caused by the decreased unsaturated fatty acid content in meat after CLA feeding, which increased the melting point of the fat.

Adipose Tissue↗
PubMed2002

Effect of antioxidants on the quality of irradiated sausages prepared with turkey thigh meat.

The effects of antioxidants on the flavor and color of electron-beam-irradiated turkey sausages were studied. Sausages were prepared from turkey thigh meat, NaCl (2.0%), phosphate (0.5%), water (10%), and one of five antioxidant treatments (none, vitamin E, sesamol, rosemary extract, or gallic acid at 0.02%). Sausages were stuffed and cooked in an 85 C smokehouse to an internal temperature of 74 C, then chilled and sliced to 1.5-cm thickness, and vacuum-packaged. Packaged sausages were randomly divided into three groups and irradiated at 0, 1.5 or 3.0 kGy, using an electron beam. Volatiles, color, 2-TBA-reactive substances values, and sensory characteristics were analyzed. The antioxidant effect of sesamol was the highest, followed by vitamin E and gallic acid; rosemary extract had the weakest antioxidant effect. Irradiation induced red color in sausages, but addition of gallic acid, rosemary extract, or sesamol reduced it. Gallic acid was very effective in lowering the redness of irradiated and nonirradiated sausages. The redness (a*) values of sausages with added gallic acid that were irradiated at 0, 1.5, and 3.0 kGy were 1.49,2.03, and 2.29, respectively, whereas those of control sausages under the same irradiation conditions were 2.58, 2.81, and 3.25, respectively. The reduction of redness in irradiated sausages by antioxidants was not related to CO, because antioxidants had no effect on CO production by irradiation. The amount of total volatiles was decreased significantly by antioxidants, but antioxidants had minimal effect on the off-flavor of turkey sausages induced by irradiation.

Animals↗
PubMed2002

Quality characteristics of irradiated ready-to-eat breast rolls from turkeys fed conjugated linoleic acid.

The objective of this study was to determine the effect of irradiation on the quality of ready-to-eat (RTE) breast rolls from turkeys fed conjugated linoleic acid (CLA). The oxidative stability of RTE turkey rolls was improved by the dietary CLA treatment. Irradiation increased the production of acetaldehyde, 3-methyl-butanal, 2-methyl-butanal, and total volatiles in turkey rolls but had little effect on other aldehydes. Irradiation also produced new volatiles, including sulfur compounds, not detected in nonirradiated turkey breast rolls. We detected significantly higher amounts of alkanes with nine or higher carbons in irradiated samples than in nonirradiated samples. Irradiation increased the redness of RTE turkey breast rolls, but the degree of redness and the amount of total volatiles decreased with storage. CLA treatment lowered the redness (a*) and increased the lightness (L*) of RTE turkey breast rolls during the entire storage period. Sensory evaluation revealed that irradiation produced off-flavor, but CLA and irradiation did not influence the texture and juiciness of RTE turkey breast rolls. Consumers did not like the off-flavor but preferred the color induced by irradiation to nonirradiated RTE turkey breast rolls.

Animal Feed↗