Jorge Antonio Ferreira de Lara

Características de carcaça e qualidade de carne de novilhos superprecoces de três grupos genéticos

The objective of this work was to evaluate carcass parameters, physicochemical characteristics and quality of meat of young bulls. Three genetic groups with 8 Nelore (N), 18 ½ Abeerden Angus ½ Nelore (AN), and 18 ½ Limousin ¼ Abeerden Angus ¼ Nelore (LAN) animals, with ages varying between 7.5 and 11.5 months at the beginning of the experiment, slaughtered after 143 days of confinement, were evaluated. AN animals were heavier at slaughter and showed higher average daily weight gain, higher hot carcass weight and carcass length; LAN animals had higher carcass yield and rib-eye area. LAN animals showed 72% convex carcasses, while 83% of AN and 100% of N carcasses were classified as subconvex. LAN and AN meat showed no significant difference (p>5%) in shear force values, which indicates the possibility of use of 50% of Bos indicus genotypes without loss of meat tenderness. The carcass and meat characteristics of the AN, LAN and N genetic groups comply with market specifications and are adequate for slaughter at 15 months of age, which makes the system for production of young bulls viable.

Fresh pasta enrichment with protein concentrate of tilapia: nutritional and sensory characteristics.

With the goal of developing and characterizing the nutritional and sensory aspects of fresh pasta supplemented with tilapia protein concentrate, four types of pasta were prepared, with inclusion of 0, 10, 20, or 30% of tilapia protein concentrate. Linear effects were observed (P < 0.01) in crude protein, total lipids, ash, carbohydrate, and caloric values; these parameters increased with increasing amounts of tilapia protein concentrate in the pasta. The concentration of Na, P, Ca, Mg, and Zn increased linearly (P < 0.01) in correlation with the increase in protein concentrate content, while Fe content decreased linearly (P < 0.01). In the sensory analysis, texture, overall impression, and the acceptance index demonstrated a cubic regression (P < 0.05), with the inclusion of 20% protein concentrate yielding the best scores. Including up to 30% of tilapia protein concentrate in pasta yields an increased nutritional value, but based on the sensory results, 20% of tilapia protein concentrate in pasta is the recommended maximum level.

Avaliação físico-química e microbiológica da carne soleada do Pantanal

Soleada beef is similar to sun-dried beef, and it is typical of Pantanal region. The aim of this study was to assess the physicochemical and microbiological variables of soleada beef produced in a model system. The effects of freezing technology resources and vacuum packing on the microbiological variables were assessed. Hence, biceps femoris samples were prepared, and the variables pH, water activity, chloride content, and water loss through pressure, sweating, and cooking were evaluated. The samples were separated into two aliquots; one was analyzed immediately and the other was vacuum packed and frozen. The S. aureus and E. coli count was done in the raw material, soleada beef in natura, and in frozen and vacuum packed soleada beef. Water activity with an average value of 0.97, pH of 5.72, and chloride content around 2.7% suggest a product with short shelf life, and which can serve as a substrate for the growth of pathogenic microorganisms, harmful to the human body. Freezing and vacuum packing are not adequate resources for the preservation of the traditional soleada beef.

Encurtamento pelo frio de fibras musculares oxidativas de bovinos pela técnica de NADH-TR

Bovine carcasses quickly cooled may develop a muscle contraction known as cold shortening. This process, harmful to meat texture, occurs mainly in the oxidative muscle fibers. This work was aimed at studing an analytical tool to distinguish these fibers and to evaluate, more precisely, the muscle contraction through the measurement of sarcomeres length. Longissimus dorsi muscles of 12 heifers were used as samples. Samples from one of the half carcasses were fast cooled and the samples from the others half carcasses were slowly cooled. An analytical technique based on Nicotinamide Adenine Dinucleotide - Tetrazolium Redutase (NADH-TR) methodology was performed to measure, by microscopy, the red fibers sarcomeres lenghts. Temperature and pH drops in the samples, shear force and rib eye area were also evaluated. Results pointed out that the temperature is the main responsible for the sarcomere length in the fast cooling and that, when slow cooling is performed, the influence of this parameter is less important. These results indicate that the NADH-TR technique is able to estimate cold shortening occurrence in bovine skeletal muscles.

Pre-Slaughter Stress Affects Ryanodine Receptor Protein Gene Expression and the Water-Holding Capacity in Fillets of the Nile Tilapia.

Current study evaluated the effect of pre-slaughter stress on serum cortisol levels, pH, colorimetry, water-holding capacity (WHC) and gene expression of ryanodine receptors (RyR1 and RyR3) in the Nile tilapia. A 3x4 factorial scheme experiment was conducted comprising three densities (100, 200, 400 kg/m³) with four transportation times (60, 120, 180, and 240 minutes).Transportation times alone reduced cortisol levels up to 180 minutes, followed by increased WHC and mRNA expression, RyR1 and RyR3 (200 kg/m³ density). No effect of density x transportation time interacted on the evaluated parameters. Results provided the first evidence that pre-slaughter stress affected ryanodine gene expression receptors and, consequently, the water-holding capacity in tilapia fillets.