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item Tunick, Michael
item Van Hekken, Diane

Submitted to: Journal of Texture Studies
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2002
Publication Date: 5/1/2003
Citation: Tunick, M.H., Van Hekken, D.L. 2003. Torsion analysis of fresh and aged cheeses. Journal of Texture Studies. 34(2):219-229.

Interpretive Summary: Consumers select a particular cheese not only because of its flavor, but also because of its texture. Texture and flavor change as cheese ages because the protein structure breaks down into smaller units. Cheesemakers use standard methods for characterizing texture of cheese as it ages. One such method is torsion gelometry, in which the twisting force needed to break a piece of cheese is related to the strength of the protein structure and the amount it has broken down during storage. In this study, torsion gelometry was applied to several cheese varieties at different stages of aging. The results show that torsion data can be used to predict protein breakdown and cheese quality. This information can be used by manufacturers to monitor the quality of their stored cheeses and adjust storage conditions to prolong shelf-life.

Technical Abstract: Torsion gelometry is a fundamental rheological test that can be performed on cheese to provide values of shear stress and shear strain. 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 alpha s1-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.