The “maturation” of milk for Parmigiano-Reggiano cheesemaking: effects on mineral equilibria and technological properties

摘要

Abstract The “maturation” of milk for Parmigiano-Reggiano cheese is characterised by natural creaming process: the full cream milk is placed in large flat vats, for about 10-12 hours, to obtain the gravity separation of milk fat. The modifications of mineral equilibria and technological properties of milk during the “maturation” phase, were studied. To this aim 24 full cream (FC) milk samples and the corresponding partially skimmed (PS) milk, by natural creaming, were analysed. PS milk evidenced higher values of both colloidal Ca/casein (+4.28%; P≤0.01) and colloidal P/casein (+4.02%; P≤0.01) ratios than FC milk. An increase of pH (+0.028; P≤0.01) and titratable acidity (+0.03 °SH/50ml; P≤0.01) was observed during the milk “maturation”. The PS milk was characterised by a higher milk clotting time (r) (+7.91%; P≤0.01) and a lower curd firmness (a₃₀) (?16.75%; P≤0.01) than FC milk. Concerning rheological properties, PS milk curd was characterised by higher values of both resistance to compression (+14.82%; P≤0.01) and resistance to cut (+15.12%; P≤0.01) than FC milk. The variations of milk characteristics observed in PS milk seems to indicate a structural modification of the native micelle during the “maturation” phase; this feature contributed to variations of rennet-coagulation and rheological properties observed in PS milk.