Effect of protective atmospheres on physicochemical, microbiological and rheological characteristics of sliced Mozzarella cheese

Mozzarella cheese slices packaged in bags of polyvinylidene chloride under vacuum (V) and using a gas mixture of equal parts of CO2 and N2 (G) were stored at 4 °C for 8 weeks and analysed at different storage times by physicochemical, microbiological and rheological characterization. Expected values of moisture, total nitrogen, soluble nitrogen at pH 4.6, and chloride contents and of pH were observed. The degradation of αs1-casein was greater than β-casein degradation, while no significant differences were observed due to the packaging methods. Coliform microorganisms were not detected, while levels of moulds and yeasts counts were acceptable. Expected values of total mesophile counts were obtained. The temperature at crossover moduli (Tc) was determined from temperature sweeps carried out by rheometry. Greater values of Tc were observed in samples G. The influence of temperature on complex viscosity was studied by an Arrhenius-type equation. Activation energy values were obtained from the solid-like region (20-40 °C) and liquid-like region (40-60 °C). A more rapid change in viscosity with temperature was observed when storage time increased and when storage method V was used.

► MAP and vacuum packaging effect on characteristics of Mozzarella cheese is studied. ► Rheometrical assays related to melting properties were used. ► Rheological analysis was used for explaining differences found. ► Potentiality of rheometrical assay to study microstructural changes is emphasized.