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Angus steers were grazed on unsupplemented pasture (CNTRL), pasture supplemented with 0.7% BW cracked corn (FLAX-0), FLAX-0 with 0.125% and 0.250% BW of whole flaxseed (FLAX-1 and FLAX-2). Six steers were grazed per treatment for 70 days, with start and finish weights of 458 and 508 kg. At 24 h post slaughter, longissimus thoracis were harvested, and steaks assigned to treatments of postmortem aging time under vacuum (PM; 3, 14 and 56 days) with or without five days of aerobic exposure (AE). Meat antioxidant status was higher (P<0.05) when feeding CNTRL and FLAX-1 than FLAX-0 and FLAX-2. Under AE, lipid oxidation was highest for FLAX-2 (P<0.05), and lowest for FLAX-1. Greatest TBARs and lowest antioxidant capacity and redness values were obtained with AE and the longer PM (P<0.05). Beef oxidative stability through AE improved by adding a low flaxseed level to supplemented corn grain, but deteriorated by adding a high flaxseed level or by extending PM.
Assuntos
Antioxidantes/metabolismo , Dieta/veterinária , Linho/química , Peroxidação de Lipídeos , Músculo Esquelético/metabolismo , Sementes/química , Zea mays/química , Animais , Animais Endogâmicos , Antioxidantes/análise , Argentina , Bovinos , Dieta/efeitos adversos , Gorduras na Dieta/análise , Linho/efeitos adversos , Embalagem de Alimentos , Qualidade dos Alimentos , Armazenamento de Alimentos , Herbivoria , Humanos , Masculino , Carne/análise , Músculo Esquelético/crescimento & desenvolvimento , Oxirredução , Pigmentos Biológicos/análise , Pigmentos Biológicos/biossíntese , Sementes/efeitos adversos , Aumento de PesoRESUMO
The objective of this study was to evaluate the fatty acid profile and qualitative characteristics of meat from feedlot young bulls fed ground soybean or ground cottonseed, with or without supplementation of vitamin E. A total of 40 Red Norte young bulls, with an initial average age of 20 months, and an initial average BW of 339±15 kg, were allotted in a completely randomized design using a 2×2 factorial arrangement, with two oilseeds, and daily supplementation or not of 2500 IU of vitamin E. The experimental period was for 84 days, which was preceded by an adaptation period of 28 days. The treatments were ground soybean (SB), ground soybean plus vitamin E (SBE), ground cottonseed (CS) and ground cottonseed plus vitamin E (CSE). The percentage of cottonseed and soybean in the diets (dry matter basis) was 24% and 20%, respectively. Diets were isonitrogenous (13% CP) and presented similar amount of ether extract (6.5%). The animals were slaughtered at average live weight of 464±15 kg, and samples were taken from the longissimus dorsi muscle for the measurement of fatty acid concentration and the evaluation of lipid oxidation and color of the beef. Before fatty acid extraction, muscle tissue and subcutaneous fat of the longissimus dorsi were separated to analyze fatty acid profile in both tissues. Supplementation of vitamin E did not affect fatty acid concentration, lipid oxidation and color (P>0.05). Subcutaneous fat from animals fed CS diet had greater C12:0, C16:0 and C18:0 contents (P<0.03). In addition, CS diets reduced the C18:1 and C18:2 cis-9, trans-11 contents in subcutaneous fat (P<0.05). The muscle from animals fed CS tended to higher C16:0 and C18:0 contents (P<0.11), and decreased C18:1, C18:2 cis-9, trans-11 and C18:3 contents (P<0.05) compared with SB. The Δ9-desaturase index was greater in muscle from animals fed SB (P<0.01). At 42 days of age, meat from cattle fed SB had a greater lipid oxidation rate (P<0.05). Meat from animals fed SB diets had less lightness and redness indices than meat from animals fed CS diets after 14 days of age. In conclusion, the addition of ground cottonseed in the finishing diets did increase the saturated fatty acid content of the longissimus dorsi. However, animals fed cottonseed exhibited greater lightness and redness of beef. In this study, the addition of vitamin E did not affect qualitative characteristics of meat.
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Ração Animal/análise , Bovinos/fisiologia , Suplementos Nutricionais , Ácidos Graxos/metabolismo , Carne/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Peso Corporal , Óleo de Sementes de Algodão , Dieta/veterinária , Ácidos Graxos/análise , Metabolismo dos Lipídeos , Masculino , Carne/normas , Sementes , Glycine max , Gordura Subcutânea/metabolismo , Vitamina E/administração & dosagemRESUMO
Meat derived from pasture feeding, is associated with a high level of antioxidants. Antioxidants are incorporated within cell membranes and protect tissues against oxidation from reactive oxygen species. This maintains the overall quality of meat and secondary products. This paper reviews the implications of incorporating natural antioxidants into fresh beef, focusing on the benefits of feeding cattle good quality pasture. Pasture samples typically have higher levels of α-tocopherol, ß-carotene, ascorbic acid and glutathione than feedlot samples. These compounds retard lipid and protein oxidation in fresh and stored meat, and preserve the color and odor quality of beef. The significance of antioxidant enzymes is variable, because their behavior depends on individual redox status before slaughter. Understanding total antioxidant activity requires information on antioxidant and pro-oxidant status. With an abundance of pasture, Argentina has a natural advantage in producing meat with a high antioxidant value.
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The objective of this study was to determine if pasture or grain diets affect oxidative/antioxidative status and the color stability of beef during retail display. Ten crossbreed steers were fed on pasture. Five of them were randomly assigned to remain on this diet, and the other five were finished on feedlot system (grain diet) during 110days until slaughter. Slices of Psoas major steaks were randomly distributed among retail display times (1, 3, 5, 7 and 9days). Lipid and protein oxidation were higher in Psoas major steaks from grain diet than in pasture diet (P<0.05). After 3days of display, lipid oxidation increased in meat from grain diet, whereas in meat from pasture diet the first evidence was after 7days (P<0.05). Protein oxidation was higher in meat from grain diet than in meat from pasture diet at day 9 of display (1.15±0.92 vs. 1.91±0.70µg/g, respectively; P<0.05). Antioxidant vitamins, α-tocopherol and ß-carotene were higher at time=0 in pasture Psoas major steaks (P<0.05) and were differentially reduced throughout storage. While α-tocopherol decreased 41% and 57% for pasture and grain beef respectively (P<0.05), ß-carotene levels remained practically unaffected in grain beef. After 7days of display "a" value was higher for Psoas major steaks from pasture diet (P<0.05). Besides, "L" parameter showed higher values for samples from grain diets but it was no affected by display time. No differences were observed between both treatments for "b" value, but a significant decrease (P<0.05) was observed along storage. Superoxide dismutase and catalase activity was stable throughout storage, while glutathione peroxidase activity decreased significantly (P<0.05). The results in this study demonstrated that the higher initial level and synergistic action (under light and air) of α-tocopherol and ß-carotene found in pasture-finished animals improved the oxidative and color stability of beef, as showed by a better retention of redness at the end of retail display.
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Buffalo meat production is increasing in Argentina. Information on meat quality and nutritional value will be useful in marketing. This work describes the oxidative stability of the Longissimus dorsi (LD) in relation to consumption of antioxidant vitamins, fatty acid composition and color deterioration during ageing. Vitamins levels found in fresh beef were 4.22±0.93; 0.24±0.05 and 0.25±0.06µg/g for α- and γ-tocopherol, and ß-carotene, respectively. Vitamin loss was almost 90% throughout an ageing period of 25 days at 2°C. Concomitantly, TBARS levels increased from 0.076±0.018 to 0.14 6±0.032mg MDA/kg beef. Hexanal and pentanal levels were low and no correlations with oxidation were detected (P>0.05). The predominant color changes in aged beef were reduced redness and yellowness with an increase in lightness (P<0.05). Vitamin levels and TBARS were used to develop a prediction equation for post-mortem aging.
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The main goal of the present work was to determine the overall antioxidant status in fresh meat from animals fed different diets and to differentiate them through their odour profiles. Attributes were evaluated in beef from pasture or grain-fed animals with (PE and GE) or without supplementation (P and G) with vitamin E (500UI/head/day). Fresh meat produced on pasture (P and PE) had higher total ferric reducing antioxidant power (FRAP) levels than meat from grain fed-animals (G and GE) (P<0.05). However, no differences were found on their ability to reduce ABTS(+) (2,2'-azino-bis-(3-ethylbenz-thiazoline-6-sulfonic acid)), indicating that total antioxidant activity was preferentially due to the reduction potential than to the quenching capacity of tissue homogenates. Two-fold glutathione (GSH and GSSG are the reduced and oxidised forms, respectively) levels were found in the P+PE group respect to G+GE meat (P<0.001). In addition, meat from pasture-fed animals presented a higher glutathione redox potential compared to grain-fed animals (-156.1±6.1 and -158.1±6.5 vs. -148.1±13 and -149.8±14.6 for P, PE G and GE, respectively), showing that the antioxidant status in fresh meat was affected by diet. Enzymatic activity of catalase and glutathione peroxidase were equivalent for all dietary groups. Only superoxide dismutase activity was slightly higher (P<0.05) in the P+PE group than in G+GE samples. Odour profile analysis was performed in relationship to antioxidant parameters. Significant linear correlation coefficients (P<0.05) were found for a set of sensors and the FRAP values. E-nose methodology successfully discriminated the odour characteristics of samples corresponding to pasture- or grain-based diet. Hence, it was possible to describe an analytical relationship between the odour profile and the antioxidant power of fresh meat.
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Argentine meat has been traditionally produced on pasture. However, to comply with some market requirements, grain finishing is becoming more common among producers. The main goal of the present work was to study lipid oxidation in fresh meat from animals fed different diets in relationship with their antioxidant vitamin status. Attributes were evaluated in beef from pasture or grain-fed animals with (PE and GE) or without supplementation (P and G) with vitamin E (500 UI/head/day). Fresh meat produced on grain (G and GE) had higher fat (4.0±1.6 and 4.7±1.4 g/100 g) and cholesterol content (51.0±3.0 and 52.0±4.0 mg/100 g) than meat from pasture (P and PE) fed animals (2.7±1.2 to 2.9±1.1 g/100 g and 48.0±5.0 to 49.0±4.0 mg/100 g of intramuscular fat and cholesterol respectively). Fatty acid composition was clearly affected by diet. Beef from pasture-fed cattle had higher percentage of linolenic acid, less linoleic acid and, overall, higher percentage of polyunsaturated fatty acids than beef from grain-fed animals (P<0.05). Thiobarbituric acid reactive substances number and volatile levels of hexanal, pentanal, heptanal, octanal and 3-methylbutanal were higher in grain than in pasture samples (P<0.05). P+PE meat had higher content of antioxidant vitamins than G+GE samples (P<0.001). Values ranged from: 15.92±3.48 (G) to 17.39±4.29 (GE) and 25.3±10.0 (P) to 21.98±5.11 (PE) µg/g of ascorbic acid; from 1.05±0.73 (G) to 1.76±0.97 (GE) and 3.08±0.45 to 3.91±0.74 µg/g of α-tocopherol; and from 0.06±0.03 (G) to 0.05±0.01 (GE) and 0.45±0.21 (P) to 0.63±0.27 (PE) µg/g of ß-carotene. In addition, principal component analysis clearly separated grain from pasture samples regardless of their supplementation with vitamin E. This level of supplementation did not improve the antioxidant status of fresh meat (P>0.05). We conclude that pasture diet contributes natural antioxidants in sufficient amounts and is an efficient way to prevent lipid oxidation in fresh beef.
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An improved method for the analysis of phospholipids by normal-phase HPLC is described. Addition of methanol and acetonitrile to a gradient based on 2-propanol/hexane/water promoted a rapid separation of major classes of bovine surfactant phospholipids (PL) by using a conventional silica column. The use of an ELSD permitted an accurate analysis of a mixture of PL. Calibration curves were linear within the range of 5-40 microg with detection limits below 1 microg for PE and PC, and CV ranged from 0.6 to 9.6%. PL present in surfactant homogenates were separated by a solid-phase extraction (SPE) procedure before HPLC analysis. This methodology gave a recovery of 95% and combined SPE-HPLC and quantification of biological PL within a 30-min run. The use of ELSD detection of the eluted compounds was precise, linear, and sensitive.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Fosfolipídeos/análise , Calibragem , Fosfolipídeos/química , Fatores de TempoRESUMO
Chorizo is a raw sausage, which is manufactured with beef, pork meat and pork fat, additives and spices. In Argentina, the expenditure of chorizo is through butchery and supermarkets where the product can be found packaged in both polyethylene films and vacuum sealed pouches. In the latter type of packaging an appearance problem has been detected in relation to drip loss. The aim of the work was to solve such problem through the incorporation of soy protein isolate (SPI). The sensory, microbiological and chemical stability of the product and its drip loss during a storage period of 14 days were studied. By adding a 2.5% SPI, the drip loss was prevented without introducing any change in the flavour, aroma and juiciness characteristics of the product. These sensory attributes were kept stable during the storage period studied. Chemical composition, oxidative and microbiological stability were not affected by the addition of SPI during the storage period, being similar for added and non-added SPI samples. Finally, SPI can be used in chorizos to improve their overall appearance during refrigerated storage while the product quality characteristics are not altered.
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The aim of this paper is to report for the first time the association between bronchiolo-alveolar carcinoma and acute myocardial infarction (AMI). Two patients suffering from this association were studied. A 59 year old male, diabetic, alcoholic and smoker was admitted because a diaphragmatic AMI. An interventricular septal defect and papillary posterior muscle rupture were confirmed at autopsy. A 0.8 cm diameter friable mass was found in the right lung superior lobe. The second case was a 69 year old male, smoker, who presented with a diaphragmatic and right ventricular posterior wall AMI. A round 1 cm diameter tumor was observed at the right lung superior lobe. It had a caseous aspect lying over a fibrous scar. Both cases had severe right coronary artery narrowings with recent occlusive thrombi. The cardiac valves were free of non-bacterial thrombotic endocarditis. Therefore the possibility of coronary embolization was discarded. As lung carcinomas produce vasospastic and thrombogenic mucins, these substances could have been responsible for the acute coronary thrombosis.