O objetivo deste trabalho foi avaliar a eficiência de uma membrana cerâmica (0,8 µm de porosidade) na filtração de soro de leite de búfala (SLB) e comparar a qualidade microbiana e nutricional do filtrado com aquela do soro proveniente do processo de pasteurização (65 ºC, 30 minutos). Foram realizadas sete repetições em que as amostras de SLB colhidas, antes e após a filtração (SF) ou pasteurização (SP), foram caracterizadas quanto ao pH, densidade (d), acidez lática (ºD), umidade (U), extrato seco total (EST), teor de gordura (TG), lactose (Lac) e proteínas (Pro), e também quanto ao número de bactérias aeróbias mesófilas. As amostras in natura de SLB apresentaram médias de pH = 6,31, acidez = 10,00, U = 89,60, EST = 10,40, d = 1,027, P = 1,19%, Lac = 5,84%, e G = 1,20%. Os resultados indicaram que houve uma redução de carga microbiana média de 4,04 x log UFC.mL-1 em AS para 1,50 x log UFC.mL-1 nas amostras de SP e para 0,70 x log UFC.mL-1 nas amostras de SF. Portanto, a microfiltração por membrana cerâmica foi mais eficiente que o processo de pasteurização lenta em relação à redução de carga microbiana.

The purpose of this work was to evaluate the efficiency of a ceramic membrane with (porosity of 0.8 µm) to filter the whey of buffalo's milk aiming to reduce the microbial charge and characterize the nutritional value of this product. The results were compared with those of the pasteurization process (65 ºC, 30 minutes). Seven assays were carried out by submitting the samples to filtration or pasteurization processes. The samples were then analyzed before (SBF) and after (SAF) filtration and after pasteurization (SAP) regarding the mesophyllic aerobic bacteria count. The milk whey samples before filtration (SBF) was also characterized regarding physico-chemical parameters (pH, density, acidity, humidity, total dried extract, concentration of total fats, lactose, and protein). The results indicate a reduction of the microbial charge from 4.04 x log CFU.mL-1 to 1.50 x log CFU.mL-1 in the SAP samples and to 0.70 x log CFU.mL-1 in the SAF samples. Other findings were pH = 6.29, acidity = 10.07, humidity = 89.94, total dried extract = 10.06, density = 1.029, protein = 1.19%, lactose = 5.85%, and fat = 1.37%. The microfiltration process using a ceramic membrane proved more efficient than the pasteurization process regarding microbial charge reduction.

The aim of this work is to characterize physically and mineralogically six samples of natural and industrialized bentonites from Paraíba, Brazil, and to study its rheological properties to be used as a components of water based drilling fluids. Also it is intended to compare the evolution of the mineralogical composition and rheology of these clays after 40 years of exploitation. The natural bentonite clays were transformed into sodium bentonite by addition of concentrated Na2CO3 solution. The suspensions were prepared with 4.86% w/w to measure their rheological properties (apparent and plastic viscosities and water loss). The results showed that: i) the samples present typical mineralogical compositions of bentonites, but after four decades of exploitation, presents inferior quality and ii) among the clays samples, only one presented satisfactory rheological properties be used as a components of water based drilling fluids.