La estabilidad oxidativa de la carne fresca, madurada y refrigerada de novillos Aberdeen Angus producidos en Uruguay

Tribunal: Pérez Clariget, Raquel; Purslow, Peter; Salhi, MaríaEsta Tesis de Doctorado se dividió en tres partes. En la primera, se estudió el impacto de los tres sistemas de producción que se realizan en el Uruguay (pasturas, pasturas más suplementación de granos y feedlot) sobre la estabilidad oxidativa de la carne de novillos Aberdeen Angus, fresca y madurada. Se observó un efecto del sistema de producción sobre los niveles de oxidación lipídica en la nalga madurada y la paleta fresca, donde el sistema pastura más suplemento (P+S) presentó una mayor oxidación, y sobre la oxidación proteica en la nalga (Pastura>P+S, Feedlot) y en la paleta (P+S>Pastura). Se encontró una mayor actividad de la catalasa en el bife angosto del sistema pastura comparado con los otros dos sistemas, y una mayor actividad de la superóxido dismutasa en los sistemas pastura y feedlot comparado con el P+S (bife angosto) y en sistema pastura comparado con feedlot (paleta). La actividad de la enzima glutatión peroxidasa (GPx), fue mayor en la carne del sistema feedlot comparado con los otros dos sistemas (en los tres cortes estudiados). El sistema pastura presentó una mayor capacidad antioxidante comparado con el sistema feedlot, en el bife angosto madurado. En la segunda parte de la tesis, se evaluó el efecto de la suplementación con selenio orgánico, en la dieta de novillos Aberdeen Angus en sistema feedlot, sobre la estabilidad oxidativa de la carne fresca y madurada. Se encontró una menor oxidación proteica y una mayor actividad de la enzima GPx en el corte bife angosto, y una mayor actividad de la catalasa en los cortes lomo y bife angosto, de novillos suplementados comparado con los no suplementados. En la tercera parte, se quiso determinar si la carne de novillos Aberdeen Angus alimentados a pasturas y en sistema feedlot, presenta una estabilidad oxidativa y del color diferente, al ser sometidas a exposición en vitrina refrigerada. Se encontró una menor oxidación lipídica y proteica, y una mayor estabilidad del color en la carne del sistema pastura comparado con la de feedlot, durante la exposición. Esto es respaldado por el mayor contenido de β-caroteno y α-tocoferol (antioxidantes) encontrado en la carne fresca de novillos a pasturas

From the fatty acid content perspective, is it healthier to eat a hindquarter or a forequarter cut? Angus steers in pasture or concentrate systems

In this study, Biceps femoris (BF) and Triceps brachii (TB) of Aberdeen Angus steers, from the hindquarter and forequarter, respectively, were compared from their fatty acid composition, lipid health, and lipid enzyme activity indices points of view. For this, ten animals were produced in a pasture system and ten were finished in a concentrate-based system. TB presented a significantly higher intramuscular fat, saturated C14:0, C14:1, C16:1, CLA, and MUFA content. BF presented a significantly higher LA, ARA, EPA, DPA, DHA, PUFA, total n-6, and n-3 content, and a significantly higher PUFA/SFA ratio. Significant differences between muscles were found regarding lipid enzyme activity indices, but not concerning atherogenic and thrombogenic indices. Also, meat from different feeding systems was compared, where meat from pasture presented a better fatty acid composition regarding cardiovascular health aspects. In conclusion, BF presented a better composition in the most nutritionally relevant fatty acids, with exception of CLA

Oxidative stability, fatty acid composition and health lipid indices of Longissimus dorsi muscle from Aberdeen Angus steers produced in different feeding systems

The aim of this study was to evaluate the oxidative and anti-oxidative status of unaged and aged Longissimus dorsi (LD) muscle obtained from a commercial abattoir. Also, fatty acid composition and calculated health lipid indices of meat were compared. Animals slaughtered were Aberdeen Angus steers raised in three typical feeding systems of Uruguay: (1) Pasture (n=10), (2) Pasture + Supplement (P+S) with corn grain (n=10), and (3) Feedlot (n=10). Feeding had no effect on lipid and protein oxidation but the antioxidant enzymes activities were affected as follows: superoxide dismutase (SOD): Pasture, Feedlot > P+S; catalase: Pasture > P+S, Feedlot; glutathione peroxidase (GPx): Feedlot > P+S > Pasture. Total antioxidant potential, determined by Fenton reaction, was higher in aged meat from Pasture compared with aged meat from Feedlot. Meat from Pasture and P+S presented a higher eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and total n-3 content and a lower lipid content, n-6/n-3 ratio and trombogenic index compared to meat from Feedlot. In conclusion, Pasture seems to produce a more resistant meat against induced oxidation processes, particularly after ageing, and a healthier meat together with meat from P+S system, regarding fatty acid composition and lipid indices, compared to Feedlot

Catalase, SOD and GPx Activities in triceps brachii muscle from Aberdeen Angus steers finished on pasture, pasture and concentrate, or concentrate

Three feeding system were investigated to determine if any of them is more suitable to ensure a better antioxidant protection to meat from Triceps brachii muscle of Aberdeen Angus steers. They were finished on pasture, pasture + concentrate with corn grain, or concentrate alone. TBARS, protein carbonyls and antioxidant enzymes activities have been determined in fresh and aged meat (14 days in vacuum, 1-2°C). The level of TBARS ranged between 0.59-0.64 mg MDA/kg meat, whereas levels of protein carbonyl ranged between 0.18-0.22 mmoles DNPH/mg protein. The activities of catalase and superoxide dismutase are higher in fresh meat of animals fed pasture, compared to those finished on pasture and concentrate, or on concentrate alone. Glutathione peroxidase (GPx) showed higher activities in meat of animals finished on concentrate in comparison those finished on pasture and concentrate, or pasture. However, the results of the investigation do not allow the advising, for now, for the most suitable feeding system for finishing steers that help producers to preserve meat from lipids and protein oxidation. More investigations are necessary to highlight the feeding conditions, which could influence the activities of antioxidant enzyme catalase, SOD and GPx in meat

Compuestos bioactivos de la carne

La carne es un alimento completo, no solo por el contenido de nutrientes de alta biodisponibilidad, sino por el contenido de compuestos particulares con interesantes efectos nutracéuticos

Lactate Kinetic in Chicken pectoralis Muscle

Abstract We studied the effects of different dietary starch sources fed to poultry on the quality attributes and oxidative damage in fresh and aged chicken pectoralis muscle. In a corn-soya diet, 300 g.kg -1 of the starch from ground corn was replaced by starch from broken corn, ground sorghum or pure starch, and fed for 11 days prior to slaughter to male broilers. In pectoralis muscle, pH rate, colour, drip loss, glycogen and lactate were measured at 10, 45, 90 minutes and 24 hours postmortem. Protein, lipid oxidation and haem iron were measured in fresh and aged meat. Sorghum starch caused a lower initial pH, while broken corn and pure starch gave higher pH in the pectoralis muscle. Ground corn and pure starch sources showed the lowest pH (45 min postmortem) indicating faster decline curves. Ground sorghum produced a lower level of residual glycogen in muscle and a lower rate of protein oxidation while the highest glycogen and a higher protein oxidation rate was observed with pure starch Type of starch sources in diet received prior to slaughter affect the quality parameters in poultry meat. Particularly, ground sorghum improved meat quality whereas pure starch provoked a higher protein oxidation

pH, drip loss, colour, lipids and protein oxidation of meat from Pampa-Rocha and crossbreed pigs produced outdoor in Uruguay

Pampa-Rocha (PP) is a local rustic pig reared on pasture in Uruguay to produce meat, mainly in a familiar scale system. Meat quality parameters for Longissimus dorsi (LD) and Psoas major (PM) muscles from PP and its crossbreeding with Duroc (PD) and Large White (PL) genetic type were determined. The pH showed no genetic type main effect. Values of pHu (24 hours Post-mortem) fail within advised values for pig meat and ranged for LD 5.48-5.69 and for PM 5.52-5.69. The drip loss for fresh meat, at 24 hours Post-mortem, showed relatively low levels with values ranged 2.23-4.50 for LD and 1.25-2.51 for PM. After five days the drip loss showed values ranged 5.21-9.33 for LD and 3.96-6.65 for PM. After ageing (1-2°C in vacuum) drip loss, at 24 hours Post-mortem, ranged between 1.43-2.47 for LD and 1.62-1.77 for PM while after five days, drip loss showed values ranged 3.73-3.97 for LD, and 3.31-4.12 for PM. Drip loss showed a significant main effect with PP having a lower level than PD and similar to PL. For colour study, PP showed a darker meat than PD and PL, and no main effect of ageing. The lipids oxidation level was similar for the three genetic types and no main effect was observed. The protein oxidation showed a similar level for the three genetic types and fresh meat showed more protein oxidation than aged meat

Dietary organic and inorganic selenium on liver glycogen and lactate, pHu, color and drip loss of chicken pectoralis and gastrocnemius muscles

The effect of selenium supplementation in finishing broiler diets on meat quality was studied. A corn soya based diet was supplemented with 0.3 ppm of Se from an organic (Seleno methionine; Se-Met) or inorganic source (sodium selenit

Effect of different sources of dietary starch on meat quality, oxidative status and glycogen and lactate kinetic in chicken pectoralis muscle

We studied the effects of different dietary starch sources fed to poultry on the quality attributes and oxidative damage in fresh and aged chicken pectoralis muscle. In a corn-soya diet, 300 g.kg-1 of the starch from ground corn was replaced by starch from broken corn, ground sorghum or pure starch, and fed for 11 days prior to slaughter to male broilers. In pectoralis muscle, pH rate, colour, drip loss, glycogen and lactate were measured at 10, 45, 90 minutes and 24 hours postmortem. Protein, lipid oxidation and haem iron were measured in fresh and aged meat. Sorghum starch caused a lower initial pH, while broken corn and pure starch gave higher pH in the pectoralis muscle. Ground corn and pure starch sources showed the lowest pH (45 min postmortem) indicating faster decline curves. Ground sorghum produced a lower level of residual glycogen in muscle and a lower rate of protein oxidation while the highest glycogen and a higher protein oxidation rate was observed with pure starch Type of starch sources in diet received prior to slaughter affect the quality parameters in poultry meat. Particularly, ground sorghum improved meat quality whereas pure starch provoked a higher protein oxidation