Effect of calcium addition and pH on yield and texture of Minas cured cheese / Efeito da adição de cálcio e do pH sobre o rendimento e a textura de queijo-de-Minas curado

Milk calcium concentration is a factor related to cheese texture, an important rheological property of cheese quality as perceived by consumers. This study aimed to evaluate the effect of different pH conditions (5.8 and 6.6) and calcium addition (0, 150, 300 ppm of CaCl2), on yield and nutrient retention of the clots obtained and on the texture of Minascured cheese. Clots were analyzed for wet and dry yield, percentage content and retention of protein, fat and calcium. The texture of the cheese was evaluated by instrumental and sensorial tests. No differences were observed on the wet and dry yields, or on the protein content, fat and calcium retention of clots produced in the different experimental conditions. The instrumental evaluation showed that calcium addition significantly influenced the texture of cheeses, regardless of the pH of milk clotting. The sensory panel did not find a difference in the hardness ofcheeses produced at the same pH of milk clotting in function of CaCl2 addition. There was no difference in the texture of Minascured cheese due to the calcium addition to milk for dairy product consumers, which brings a new perspective on manufacture for cheese markers.

Avaliou-se o efeito de diferentes condições de pH ­5,8 e 6,6 ­e da adição de cálcio ­0, 150, 300ppm de CaCl2 - sobre o rendimento, a retenção de nutrientes nos coágulos produzidos e a textura de queijo-de-Minas curado. Foram analisados nos coágulos os rendimentos úmido e seco, o percentual e a retenção de proteína, de gordura e de cálcio. A textura dos queijos foi avaliada por testes instrumental e sensorial. Não foram observadas diferenças nos rendimentos úmido e seco, no conteúdo percentual e na retenção de proteína, gordura e cálcio nos coágulos produzidos em diferentes condições experimentais. A análise instrumental mostrou que a adição ou não de cálcio influenciou a textura dos queijos, independentemente do pH de coagulação do leite. O painel sensorial não diferiu quanto à dureza dos queijos produzidos em um mesmo valor de pH de coagulação do leite mediante a adição de CaCl2. Para os consumidores, não houve diferença na textura do queijo Minas curado em razão da adição de cálcio ao leite. Isto traz nova perspectiva na fabricação para os produtores de queijo.

Utilização de Lactobacillus acidophilus e de acidificação direta na fabricação de queijo de minas frescal / Lactobacillus acidophilus and of direct acidification to minas frescal cheese production

Três procedimentos foram adotados na elaboração de queijo de minas frescal: fabricação tradicional, com adição de ácido lático e com Lactobacillus acidophilus. As amostras dos queijos foram analisadas quanto à composição e, durante o período de estocagem de 30 dias, quanto à acidez - pH e acidez titulável - e contagem de L. acidophilus. A análise sensorial foi realizada por métodos sensoriais afetivos. A composição dos queijos nos diferentes procedimentos apresentou-se de acordo com os padrões esperados, com exceção do teor de gordura, que foi maior no queijo com adição de ácido lático. Durante a armazenagem, ocorreu aumento da acidez titulável em todos os procedimentos. A contagem de L. acidophilus foi acima de 10(8)UFC/g, caracterizando populações suficientes para classificar o queijo como alimento probiótico. Na análise sensorial, o de queijo de minas com a adição do probiótico foi o preferido pelos julgadores. O queijo de minas frescal foi apropriado para incorporação do probiótico, e o uso de L. acidophilus melhorou a qualidade sensorial e não alterou os parâmetros físico-químicos.

Minas frescal cheese was produced in three different procedures: traditional manufacturing; with the addition of lactic acid; and with Lactobacillus acidophilus. Cheeses samples were analyzed for composition, and during the stock period of 30 days for acidity and L. acidophilus count. The sensory analysis was carried out through sensory affective methods. The composition of cheeses in different treatments presented results in accordance to the standards expected for the product, except for fat content, which was higher in cheese with the addition of lactic acid. During the stock period, an increase of titulable acidity in all treatments was observed. The L. acidophilus count was above 10(8)UFC/g, characterizing sufficient population to classify the cheese as a probiotic food. At the sensory analysis, it was attested that the cheese which had the addition of probiotic was preferred among the tasters. The Minas Frescal cheese was appropriate for incorporation of probiotic and the use of L. acidophilus in cheese improved the sensory quality and did not alter the physicochemical parameters.

Effect of pH on characteristics of low-moisture Mozzarella cheese during refrigerated storage.

This study evaluated the effect of cheese pH on proteolysis, calcium distribution, and functional characteristics of Mozzarella cheese. On 4 occasions, cultured low-moisture part-skim Mozzarella cheeses were obtained from a commercial producer on the day after manufacture. Cheese blocks were randomly assigned to 2 groups. One group was shredded, subdivided, and exposed to either ammonia vapor to increase the pH or HCl vapor to decrease the pH. Samples were vacuum packaged, stored at 4 degrees C, and analyzed for pH 4.6 and 12% TCA soluble nitrogen, apparent viscosity, free oil, and water-soluble calcium on days 5, 12, 22, and 40. The 2nd group was sectioned into 23-mm thick slabs and similarly exposed to either ammonia vapor to increase the pH or HCl vapor to decrease the pH. The slabs were vacuum packaged, stored at 4 degrees C, and analyzed for pH 4.6 and 12% TCA soluble nitrogen, TPA hardness, springiness and cohesiveness, and meltability on days 17, 29, and 41. Data were analyzed by ANOVA according to a spilt-plot design. Experimentally induced pH differences persisted and significantly affected TPA hardness, apparent viscosity, meltability, and water-soluble calcium throughout 40 d of storage, but did not affect soluble nitrogen changes. Thus, cheese pH affected functional characteristics and calcium distribution but did not affect proteolysis rates. Higher cheese pH resulted in a harder cheese that required longer aging to develop desirable melting characteristics, whereas cheese with lower pH developed desirable melting characteristics more quickly but had a shorter functional shelf life.