Rheological properties of cheddar cheese during heating and cooling

Rheological properties of different Cheddar cheeses were characterized using a dynamic test. Cheddar cheeses with four fat contents (15.3, 22.8, 37.3, and 45.6% fat in the dry matter-FDM) and two moisture contents (58.1 and 62.4% moisture in non fat portion-MNFP) at 2, 4, 12, and 24 wk old were used in this study. Time sweep mode was used to characterize the elastic (G') and viscous (G") properties of Cheddar cheese at a constant frequency of 1 Hz and strain 0.5%. G' and G" of the cheese were determined during heating from 25 to 60degreesC and cooling from 60 to 25degreesC. G' decreased from 9.0 to 0.07 MPa during heating and increased from 0.07 to 9.0 MPa during cooling of Cheddar cheese. G' showed similar trend as that of G' although magnitude of change were about one log higher. The reduction in % FDM of Cheddar cheese increased G' from 5.5 to 9.0 MPa and increased G" from 2.5 to 6.0 MPa at 25degreesC. A similar trend was observed at other temperatures. Proteolysis during ripening of cheese lead to decrease in G' and G" value for different fat Cheddar cheese at 60degreesC but differences were not statistically significant at 25degreesC. However, G' increased for high moisture Cheddar cheese (62.4% MNFP) from 1.6 to 4.4 MPa at 25degreesC and difference were not significant at 60degreesC.