Salting Technology For Pizza Cheese And Its Kinetics

Pizza cheese belongs to the low-moisture Mozzarella cheese, NaCl contributes to the flavor and preservation. This dissertation researched the salting technics for pizza cheese, worked out a corresponding kinetics model, studied the effect of brine concentration and ripening time on quality of pizza cheese, then, compared the results of different salting methods. It was expected to master the salting technology and its effects on cheese, and to determine the most suitable salting method for pizza cheese processing.Single-factor experiments and orthogonal experiment were carried out for three factors: salting time, salting temperature and brine concentration. The optimized salting conditions were determined as salting temperature 4℃, salting time 8-12 h, and brine concentration not lower than 16% (w/w). The process of NaCl penetrating to cheese consumes energy, which accorded with the first-order reaction model. The results of multivariate linear regression analysis by using SPSS show that: there is good linear relationship among NaCl content of salting pizza cheese, salting time, salting temperature, and brine concentration.The effects of brine concentration, ripening time and different regions of curd on pizza cheese quality were studied, brine concentration, ripening time and interaction of them had very significant effects on free oil and expressible serum content, which increased as the decrease of brine concentration. With prolonging of ripening time, the level of free oil would increase, although the level of expressible serum would decrease sharply. For cheese proteolysis, the effect of ripening time was significant, the longer of ripening time, the higher of proteolysis degree was, but brine concentration and their interaction effect showed no significance. The different positions of cheese made extremely remarkable effect on free oil content, which is lower in surface than in center for the same salted curd. The microstructure of pizza cheese, observed under scanning electron microscope showed that, with increasing of brine concentration and prolonging of ripening time, the swelling extent of protein matrix was enhanced and the serum channels became smaller.Three salting methods (mixing milled curd with dry salt; stretching cheese in hot brine; salting young cheese in cold brine after demolding) were compared. Hardness, springiness, adhesiveness, cutting property and prevention of microorganism contamination for cold brine salting cheese were better than that of the other two methods, thus, better quality pizza cheese could be made though cold bring salting method.