The rheological and fracture properties of Gouda cheese

The rheological and fracture behaviour of Gouda cheese was studied. Methods for determining these properties of visco-elastic materials are described. Application of the theory of fracture mechanics, after modification and expansion, to visco-elastic materials with a low or no yield stress is discussed. For such materials, of which Gouda cheese is an example, the flow properties greatly affect the fracture behaviour.

From the effect of variation in composition (fat, water, NaCl and Ca content, pH) and maturation on the behaviour of Gouda cheese, it may be concluded that this cheese may be considered as a composite material. Fat particles act as a filler in a swollen protein matrix. The amount of fat and the rigidity of the fat particles affect the rigidity of the cheese. Factors like pH, water and NaCl content, that change the properties of the protein matrix, clearly affect the -rheological and fracture behaviour, e.g. the rigidity and the shortness, of the cheese. The trends of these changes on the protein matrix are similar to those on rennet and acid skimmilk gels under various conditions .

As an example of the importance of the experimental results for cheese manufacturing, the relation between the pH of cheese and eye or slit formation was studied.