Rheological, melting and microstructural properties of Cheddar and Mozzarella cheeses affected by different freezing methods.

摘要

Three cheeses were treated by (1) blast, (2) precooling plus blast, (3) liquid nitrogen and (4) precooling plus liquid nitrogen freezing methods. Mozzarella I and Cheddar cheeses treated by all methods had lower shear strength than their controls, excepting Mozzarella I treated by (1) was similar to its control. Mozzarella II treated by (1) and (2) had higher shear strength than its control but by (3) and (4) it had less. The failure stresses of Cheddar and Mozzarella I cheeses treated by (1) and (2) were significantly lower than their controls, while treated Mozzarella II had opposite results. Mozzarella I treated by (2) had meltability similar to its control and by (1) had lower meltability. Mozzarella II meltability was significantly reduced by (1) and (2). Stretchability was greatly improved using both methods for Mozzarella I but not for Mozzarella II. Cryo-stage Scanning Electron Microscopy (SEM) showed that the microstructural differences caused by (1) and (2) were apparent in Cheddar and Mozzarella II but not in Mozzarella I.