SMALL AMPLITUDE OSCILLATORY SHEAR STUDIES ON MOZZARELLA CHEESE PART-II - RELAXATION SPECTRUM

The frequency dispersion of dynamic mechanical spectra of a low-moistu re, part-skim and a low-fat, part-skim Mozzarella cheese are presented , Small amplitude oscillatory shear measurements within the linear vis coelastic range (0.05% strain) were made over 12 weeks of storage, Pro teolysis during storage led to softening of the cheeses and thus decre ases in storage (G') and loss (G '') moduli. Master curves (at a refer ence temperature of 40C) were obtained by shifting the temperature-dep endent frequency dispersion of storage modulus, There was no significa nt change in G' after 4 weeks of aging. The variation of relaxation ri me and viscosity spectrum of both cheeses with age were obtained from the master curves using the generalized Maxwell model and nonlinear re gression analysis. With maturation the viscosity distribution of corre sponding Maxwell elements shifted towards smaller values, indicating t hat cheeses become softer and melt more easily.