Determinação de curva glicolítica em carcaças de aves PSE (Pale, soft, exsudative) e normal em linha de abate industrial

Some quality defects can cause changes in attributes of the meat, among these we can detach the PSE meat (Pale, Soft and Exudative). The PSE meat is pale, flaccid and exudative and result from sudden pH decrease while the carcass is still under high temperature. The identification of PSE meat has been done by measuring pH and L* (Lightness). However, studies suggest that a more precise evaluation of the kinetics of pH and temperature decrease has to be conducted to better understand the etiology of PSE meat in poultry. The aim of this study was to obtain the glycolytic curve for normal and PSE meat of chicken, through the pH, L* and CRA (water holding capacity) analysis. This experiment was conducted with carcasses obtained from a commercial slaughterhouse (n = 35) of Cobb lineage, 50 days old, from the same batch of creation and with the same pre-slaughter fasting time (10h). Samples of breast fillets were obtained from carcasses randomly collected immediately at the output of pre-cooling chiller, and the analysis of pH, temperature and L * were conducted in the same in times 1h35, 2h35, 3h35, 5h35, 8h35, 11h35, 14h35, 17h35, 20h35, 23h35 and 25h35 post mortem. The CRA analyzes were performed at the time of 25h35 post mortem. The pH measurements indicated that only from the 04 time (8h35 post mortem) was possible to verify an indicative of stabilization, being that PSE meat pH was 5,69±0,07, and normal meat was 5,93±0,09. The final pH (25h35 post mortem) was 5,98±0,06 and L* 57,30± 2,39 for normal meat, while for PSE meat the result was 5,72±0,06 and L* 59,44±1,51. To CRA, the average of the samples (67,19±3.13 and 64,45± 2.66) showed a difference between the normal chicken fillets and PSE respectively. The data found in this study are consistent with those reported by own research group in another slaughterhouse and contradicts similar works, but made at room temperature, indicating that for chickens under commercial conditions the resolution of rigor mortis occurs after 8h35 post mortem.

Avaliação do potencial da macrófita Pistia stratiotes na exposição de íon cromo (VI): biossorção e tolerância

The environmental pollution caused by industries has increased the concentration of pollutants in the environment, especially in water. Among the most diverse contaminants, there is the metals, who may or may not to be heavy/toxic, causing effluent of difficult treatment when in low concentrations. The search for alternative measures of wastewater effluent treatment has led to studies using phytoremediation technique through the various matrices (plant, fungi, bacteria) as means of polishing treatment to remove contaminants by means of biosorption/bioaccumulation. In order to use the phytoremediation technique for removing metals of the environmental, it have been performed bioassay with the macrophyte Pistia stratiotes. The bioassays were realized with healthy plants of P. stratiotes acclimatized in a greenhouse, at room temperature and lighting conditions during 28 days of cultivate. The cultivations were performed in glass vessels containing 1 L of the hydroponic solution with chromium (VI) in the potassium dichromate form with concentration range 0.10 to 4.90 mg L-1. The experiments were performed by Outlining Central Composite Rotational (OCCR), where the kinetics of bioaccumulation and chlorophyll a fluorescence were monitored in plants of P. stratiotes during cultivation. The collections of the samples and cultive solution were performed according to the OCCR. The chromium levels were measured in samples of P. stratiotes and the remaining solutions by the methodology of atomic absorption spectrometry by flame. The tolerance of P. stratiotes in relation to exposure to chromium (VI) was analyzed by parameters of physiological activity by means of chlorophyll a fluorescence, using the portable fluorometer PAM (Pulse Amplitude Modulation). The development of P. stratiots and their biomass were related to the time factor, while bioaccumulation capacities were strongly influenced by factors of time and chromium concentration (VI). The chlorophyll fluorescence parameters were affected by chromium and the exposure time at the bioassays. It was obtained an higher metal removal from the root in relation to the sheet, reaching a high rate of metal removal in solution. The experimental data removal kinetics were represented by kinetic models Irreversibly Langmuir, Reversible Langmuir, Pseudo-first Order and Pseudo-second Order, and the best fit for the culture solution was the Reversible Langmuir model with R² 0.993 and for the plant the best model was Pseudo-second order with R² 0.760.