No abstract

Some reaction parameters were tested in the hydrolysis of casein by papain, in order to prepare hydrolysates with high oligopeptide contents, for either dietetic or pharmaceutical purposes. Five casein hydrolysates were prepared and then fractionated by size-exclusion HPLC. The rapid correct fraction area method was used for quantifying peptides and free amino acids. Among the five reaction conditions tested, three produced similar peptide profiles. However, the use of a temperature of 37 • C and an E:S ratio of 2% is probably the most economical condition for use in large-scale manufacture. With the aim of masking the bitterness of these preparations, a new method, based on the encapsulation in lipospheres, was used. Also, second derivative spectrophotometry was used for the first time to measure the extent of encapsulation of protein hydrolysates, which changed from 50% to 83%. Moreover, the efficiency of this system was evaluated by analysing other parameters, which showed a reduction of hydrophobicity and bitterness of all samples, as well as good chemical stability during 60 days of storage under refrigeration. The electron microscopical analysis of liposheres showed an average size around 5.0 ± 1.0 µm.

No abstract

The encapsulation in lipospheres and in liposomes was used with the aim of masking the bitterness of casein hydrolysates for dietetic of pharmaceutical purposes. Papain was used for preparing three casein hydrolysates, employing different temperatures and E:S ratios. The percentage of encapsulation of these preparations was measured by second derivative spectrophotometry (SDS). Lipid oxidation over a period of 60 days, was followed by quantifying the 2‐thiobarbituric acid reactive substances (TBARS). Other analysis were performed for characterizing these vesicles, including the sensory evaluation and the measure of hydrophobicity. The results showed that these two encapsulation systems were equally efficient in reducing the hydrophobicity and the bitterness of casein hydrolysates. SDS was a useful tool in the characterization of these preparations. It is a quick and relatively low‐cost method, and indicated that the encapsulation rate in lipospheres (65%) was higher than in liposomes (59%). The TBARS method revealed the chemical stability of these preparations over the period of study (60 days).

O objetivo deste estudo foi avaliar a qualidade microbiológica de queijos Minas industrializados e artesanais comercializados em Belo Horizonte, MG. Foram coletadas 18 amostras de queijos, sendo nove do tipo Minas frescal, industrializados comercializados em supermercados; e nove do tipo Minas artesanal, comercializados no Mercado Municipal. A temperatura dos queijos amostrados foi aferida durante a fase de exposição para venda. A qualidade higiênico-sanitária dos queijos foi avaliada por meio da contagem de coliformes a 45 °C, Staphylococcus coagulase-positiva e pesquisa de Salmonella sp. Oito (88,9 %) amostras de queijo Minas frescal industrializado se encontravam em temperaturas acima do permitido no mercado varejista, e 100% das amostras de queijo artesanal estavam expostas a temperaturas inadequadas nas lojas do Mercado Municipal. Duas (22 %) amostras de queijo Minas industrializado e quatro (44 %) amostras de queijo Minas artesanal apresentaram contagens superiores ao preconizado pela legislação para coliformes a 45 °C. Em relação à contagem de Staphylococcus coagulase-positiva 100 % das amostras, tanto de queijo industrializado quanto de queijo artesanal, apresentaram contagens superiores aos padrões legais. Nenhuma amostra apresentou contaminação pela bactéria Salmonella sp. Dessa forma, a qualidade higiênico-sanitária de 100 % dos queijos Minas avaliados foi insatisfatória.