RESUMO
Sodium chloride (NaCl, 0-1.4%) and sodium tripolyphosphate (STPP, 0-0.5%) were added to Semitendinosus muscles and submitted to sous vide cooking at different temperatures (55-75°C). The effects of these three factors on pH, cooking loss, instrumental colour parameters, protein solubilization and distribution, and micro- and ultra-structure were evaluated. Quadratic surface responses equations were obtained from data (pH, cooking loss and colour parameters) as a function of the salts concentrations and cooking temperature. Both salts - alone or in combination - successfully reduced cooking loss. The best results were obtained for the combinations 0.25%STPP+1.20%NaCl and 0.25%STPP+0.70%NaCl, and temperatures between 60 and 65°C. Under these conditions, cooking loss was reduced close to 0%. pH was only dependent on STPP concentration, with a threshold concentration value of 0.25%. Temperature increment and NaCl addition produced a redness reduction. STPP incorporation recovered partially this parameter in comparison to non-added samples. Microscopy and SDS-PAGE results support the effect of the selected combinations of factors, suggesting that both salts together induced protein solubilization and gelation upon heating.
RESUMO
The aim of this investigation was to determine the possibility of using calcium chloride solution in tough muscles (Cutaneus trunci) to reduce the aging period required to increase tenderness, without introducing undesirable flavors. Muscles were marinated in 0.25 M CaCl(2) solution for 2 h and after that aged for 0, 1, 2, 3, 4, 5 and 7 days. Tenderness was evaluated by the myofibrillar fragmentation index (MFI), Warner Bratzler shear force (WBS) and sensory panel evaluation. MFI values showed significant differences between treated and control samples aged for 1, 2 and 3 days (P<0.05). MFI values of treated samples aged 3 days were similar to those obtained for the control samples but aged seven days. WBS values were not significantly different between samples. Consumer panelists preferred treated samples aged 3 days to the control ones aged 7 days. It was concluded that calcium chloride treatment can be used in Cutaneus trunci muscle to reduce the aging time required to increase tenderness.
RESUMO
This study was undertaken to determine whether prolonged QTc interval as a consequence of abnormal repolarization induced by coronary disease or antiarrhythmic drugs could be shortened by intravenous administration of magnesium sulfate. A total of 21 patients with basal prolonged QTc intervals (QTc > 500 ms) were divided in two groups: 7 with ischemic coronary disease and negative T waves (Group A), and 14 treated with antiarrhythmic drugs (Group B). Nine of the latter had negative T waves (Subgroup B-1) and five had positive T waves (Subgroup B-2) recorded in precordial leads. Nine patients were taking amiodarone and six quinidine. Magnesium sulfate was given intravenously in a bolus of 3.75 g (25% solution) over 3 min. Patients had normal electrolyte serum levels. The prolonged QTc and JTc intervals were shortened after magnesium sulfate in patients of Subgroup B-1 from the basal values [QTc 20.7% and JTc 25.4%, (p = < 0.0001 and 0.02, respectively)]. None of the patients in Group A or Subgroup B-2 experienced altered QTc or JTc intervals. While some antiarrhythmic drugs are capable of altering the refractoriness of ventricular cells, probably by causing changes in the intracellular metabolic pathways, in patients with coronary disease gaps in the membrane induced by ischemic injury let calcium enter the cells parallel with dispersion of ventricular repolarization. When secondary negative T waves are present, magnesium sulfate as an antidote probably acts as a blocking agent at the sarcoplasmic reticulum, thus reducing both QTc and JTc intervals.
