Influencia do uso de retentados de baixo fator de concentração no rendimento e na qualidade da mussarela de reduzido teor de gordura feita por acidificação direta. / Use influence of low concentration factor ultrafiltration retentates on the yield and the quality of mozzarella of reduced text of fat made for direct acidification.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Use of low concentration factor ultrafiltration retentates on composition, yield, proteolysis, rheological and functional properties, microstructure and sensory acceptability of reduced fat Mozzarella cheese made by direct acidification was evaluated. Two concentration factors (1.4 and 1.8) were compared with a control (semi-skimmed milk) and three trials were carried out. Milk, retentate, permeate, whey, stretching water and cheese were weighted and their composition were determined. Fat and protein recoveries and yield were also calculated. Titratable acidity, pH, pH 4.6-soluble nitrogen, 12% TCA-soluble nitrogen and melting of cheese were determined at 4, 11, 18, 25 and 32 d of refrigerated storage at 4°C, and at 5, 12, 19, 26 and 33 d, water holding capacity, color of unmelted and melted cheese, free oil formation and rheological properties (uniaxial compression and stress relaxation tests) were evaluated. Cheese microstructure was evaluated by Scanning Electron Microscopy (SEM) at 26 d after manufacturing and the sensory acceptability were determined at 27 d of refrigerated storage. Cheese made with retentates had lower protein and calcium contents (p<0.05), tendency of higher moisture, lower fat recovery in stretching water and higher actual yield than control cheese. The use of retentates had no significant influence (p>0.05) on pH, acidity, proteolysis, water holding capacity and melting behaviour of cheese. Free oil formation, elasticity and firmness of cheeses were reduced when using low concentration factor retentates. The levels of proteolysis increased significantly during storage, however this increase was slow which is probably associated to the small amount of rennet used in cheese manufacture. This fact is probably responsible for no alterations of the functional and rheological properties during storage. The electrophoretogram confirms the slow changes in proteolysis and indicates that it was due to residual rennet action. Cheeses made with retentates were whiter than the control cheese, probably due to the homogenization effect that could be occurred during ultrafiltration of milk. All cheeses showed a dense protein network because of fat reduction. It seems that cheeses made with retentates had a less compact protein matrix probably due to their lower protein content and tendency of higher moisture that could reflect in the rheological differences of cheeses. The sensory quality was not impaired by the use of retentates. All cheeses had good acceptability, despite of the fat reduction, that was similar to the comercial light Mozzarella cheeses. The use of low concentration factor retentates in production of reduced fat Mozzarella cheese by direct acidification is viable and how the concentration factor did not affect significantly cheese quality, CF 1.8 is recommended because of higher improvement of plant capacity. However more research is needed in order to improve functional properties, especially melting that is an important attribute of Mozzarella cheese.

ASSUNTO(S)

yield mozzarella mozzarella (queijo) - rendimento ultrafiltration ultrafiltração

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