Evaluation of the methods of measurement for functional properties of Emmental cheeses from the west of France

Three industrial Emmental cheeses from the west of France at the commercial stage were compared for physico-chemical properties (composition of cheese and juice, pH and buffering of cheese and juice, colour of the cheese, DSC of cheese and extracted fat), for rheological properties (extrusion, uniaxial compression, dynamic shear with temperature sweep) and functional or culinary properties (meltability, flowability, stretchability). The flow time in a glass tube of 17 g of grated cheese was measured after the tube had been placed in a water bath at 82degreesC for 9.5 min. Cheeses were observed by cryo-SEM and the size of fat globules was compared. Functional properties were related, and increased as the ratio of calcium in the cheese juice increased, as dynamic moduli at 90degreesC decreased, as the loss angle, maximal or measured at 90degreesC, increased and as the buffer pH decreased. No relation was found with rheological characteristics at 20 or 40degreesC. Cheese firmness increased as the pH and ashes increased. The cheese C was less functional and presented larger fat globules. Cheeses can be distinguished by DSC in the 15-35degreesC zone of fat melting and in a 40-70degreesC zone, probably resulting from different protein networks. The measure of the flow time appeared to be a simple and powerful method to differentiate the cheeses.