Torsion Analysis of Fresh and Aged Cheeses1

Abstract

Six cheese varieties encompassing a wide compositional and age range were analyzed fresh and after aging to determine correlations between casein proteolysis products, fat content, moisture content, and torsion results. Shear stress, a measure of the strength of the casein matrix, was dependent on the amount of intact αsl‐casein. Shear strain, a measure of the cohesiveness of a structure, exhibited a negative correlation with fat content and a positive correlation with moisture content. Shear strain was also correlated with the ratio of moisture to protein, an indication of the interaction between casein particles. Torsion tests provide information on the level of degradation of the casein network in cheese, which can be used by manufacturers to alter storage conditions to optimize the quality of their aged cheese., April 10, 2003

Queso Chihuahua: effects of seasonality of cheesemilk on rheology†

“…Shear stress is somewhat analogous to hardness and is a measure of the strength of the protein matrix. Shear stress decreases as the casein is degraded (Tunick and Van Hekken 2003), as evidenced in this study by the correlation between α s1 ‐CN and shear stress ( r = 0.734). The winter and spring RM shear stress values tended to be lower than those in summer, and the winter PM values tended to be lower than those in summer and spring, although these tendencies were not always significant (Table 5).…”

“…The damage to the protein matrix of the RM cheese by gas formation was presumably a contributing factor. The lack of variation in the shear strain values during storage has been observed in our laboratory in other cheese varieties (Tunick and Van Hekken 2003), suggesting that breakdown of α s1 ‐CN, the primary structural component of the protein matrix, does not substantially affect the ability of the matrix to twist prior to fracturing. The α s1 ‐CN (f24–199) peptides formed during proteolysis of α s1 ‐CN are not water soluble, remain in the protein matrix and affect the fracture of the cheese but not its strain properties.…”

Mexican Queso Chihuahua: rheology of fresh cheese†

“…Compositional data, including protein profiles, quantify the amount of milk components in the cheese matrix, whereas the rheological properties give insight into the construction of the matrix by measuring its responses to applied mechanical stress and strain. Different rheological tests examine different aspects of the components’ interactions within the cheese matrix (Tunick 2000) and are used to compare different styles of cheese and to characterize cheeses as they age (Tunick and Van Hekken 2002, 2003). Rheological definitions and baselines can be used to evaluate changes in texture because of processing and post‐production modifications and to gauge the quality, uniformity and shelf life of the cheese.…”