Physical, chemical, textural and sensory modification of portioned Parmigiano Reggiano cheese packed under different conditions

Changes in physical (colour), chemical (moisture content and proteolysis index), texture and sensory characteristics of differently packed portioned Parmigiano Reggiano cheese were monitored during three months of storage at 4degreesC. Packaging conditions were under vacuum (UV) and in modified atmosphere (MA) with 50:50 (MA1) and 30:70 (MA2) CO2/N-2 ratios. The results showed, in general, substantial changes in the differently packed products. All samples underwent proteolysis phenomena together with changes in the textural and sensory characteristics. The UV packed sample showed the occurrence of an oil dropping up phenomenon which caused significant changes in product characteristics such as an increase of cohesion, sourness and yellowness. The MA packed samples showed different textural behaviour (MA2. sample evolved towards a more cohesive and friable structure than MA1) and a similar evolution of the flavour profile that, after 90 days of storage, determined a softer taste than the unpacked cheese. Parmigiano Reggiano cheese hardness showed discordant results according to the testing method (compression, shear or shear-compression), whether it involved the fracture of cheese structure or not.