The effects of high pressure treatment on immature Mozzarella cheese

Initial investigation of the effect of processing pressure showed that maximum softening of immature Mozzarella was achieved at 200 MPa and higher pressures increased hardness. The rheology and meltability of immature Mozzarella cheese, high pressure treated at 200 MPa for 60 min, were compared to samples matured by holding at 4 degreesC. The modulus of deformability (Eo), of pressure treated samples was found to be not significantly different from that of samples held at 4 degreesC for 28 d and their plasticity, measured as TPA springiness, was not significantly different from that of samples held at 4 degreesC for 14 d. Pressure treated samples had significantly increased Arnott meltability and did not differ significantly from samples matured at 4 degreesC for 14 or 28 d. Measurements of expressible serum, C.I.E. lightness (L*) and yellowness (b*) of the cheeses suggested that internal redistribution of moisture was responsible for the pressure-induced changes. Scanning electron microscopic examination of the cheeses confirmed that moisture redistribution was involved. Proteolysis, as indicated by the water-soluble N content of the cheeses, was found not to play a major part in the changes.