Meat quality of Nellore bovine (Bos taurus indicus) supplemented with vitamin E

O objetivo deste trabalho foi estudar o efeito da suplementação com vitamina E na alimentação de bovinos Nelore, sobre as características químicas e físico-químicas da carne desses animais. Esses estudos compreenderam: i) coleta de dados objetivos da cor de vários cortes cárneos para realização de um banco de dados; ii) estudo das características físico-químicas de cortes do contra filé (traseiro) e do peixinho (dianteiro) frescos e maturados por até 21 dias; iii) e verificação de possíveis alterações das características físico-químicas, inclusive da cor, de pedaços de contra filé e de carne (patinho) moída mantidas a 18ºC, durante 6 meses. Foram utilizados 24 novilhos Nelore, com 30 meses e peso médio de 279 kg, confinados, com dieta altamente energética, por 98 dias. 12 animais foram submetidos ao tratamento com 1000 mg de acetato de alfa-tocoferol, misturados a 100 g de farelo de milho, enquanto a outra metade recebeu apenas 100 g do farelo de milho. Os animais foram abatidos quando a espessura média da gordura atingiu média de 6 mm, medida por ultra-som, entre a 12ª e 13ª costelas. Coletaram-se então diversos cortes de carnes para a determinação das análises já descritas. No contexto atual das pesquisas, pode-se considerar que a suplementação com Vitamina E em bovinos Nelore não apresentou efeito positivo sobre as características químicas e físico-químicas da carne maturada por até 21 dias e congelada por até 6 meses de congelamento.In general, the modern consumer uses to evaluate the meat quality through its attributes, such as, muscle color, thickness, tenderness and juiciness, among others. Withstanding the efforts done by Animal Science researchers for the last decades, meat quality can be lost during refrigerate or even frozen conservation due to the occurrence of fatty insaturated acid oxidation. An outlet to avoid this situation might be the use of vitamin E, as a diet supplement for animal feed. The objective of this work was to study the effects of diet supplementation with vitamin E on the physical and chemical characteristics of Nellore bovine meat. This study involved: i) objective data acquisition of color parameters of different muscle sections for data base storing; ii) study of the physical and chemical characteristics of the Longissimus dorsi and Quadriceps femuris muscles fresh and aged for 21 days; iii) and, verification of the possible modifications on the physical and chemical properties, or even color, of the Longissimus dorsi and Quadriceps femuris muscles grounded and kept at 18 ºC for 6 months. There were used 24 Nellore steers, with 30 months and 279 of mean live weight, confined and fed with highly energetic diets (73, 79 and 85 % of concentrate) for 98 days. Daily, half of the animals received 100 mg of acetate of alpha-tocopherol along with 100 g of corn meal, while the other animals were fed only with 100 g of corn meal. The animals were slaugtered when the backfat thickness, within the 12th and 13th ribs, measured by ultrasound, reached 6 mm. Boning and muscle sampling were done 24 hs after slaughter. During this period there were determined the color and pH of various fresh commercial cuts. There were collected 4 Longissimus dorsi and Supraspinatus steaks of every right half carcass, which were vacuum packed and aged for up to 21 days at 0 ºC. Another 7 steaks Quadriceps femuris were collected from the left half carcasses, packed and kept frozen for up to 6 months. There were also frozen in the same conditions, grounded samples of Quadriceps femuris collected from the left half carcass as well. The meat characteristics followed during aging and freezing were: the dry matter content, pH, water loss by exudation and cooking according to classical methods. The color of the samples was determined by a HunterLab colorimeter, using the CIELab color scale. The tenderness was determined using a WB probe with a texture analyzer TA.XT2, at a rate of 500 mm/min. The samples concentration of vitamin E and cholesterol were determined by High Performance Liquid Chromatography (HPLC). The results were statistically analyzed using the SAS software. In general, it was observed that in spite of the vitamin E concentration in the supplemented samples had been greater than from the control ones, it was not confirmed the protecting effect of this vitamin related to color or to texture of meat. The results indicated that at the acetate alpha-tocopherol concentration of the present study, vitamin E supplementation of Nellore bovine did not have influence on the physical and chemical characteristics of meat aged for 21 days and frozen for 6 months