THE EFFECT OF FILLER VOLUME FRACTION ON THE FRACTURE-TOUGHNESS OF A MODEL FOOD COMPOSITE

The fracture toughness of a model food system, consisting of Sephadex (dextran) particles in a heat-denatured whey protein matrix has been d etermined. The fracture toughness increased from 1 to 7 kPa m(1/2) wit h an increase in the particle volume fraction from 0 to 0.56, which is in a manner similar to engineering materials. Microscopic examination of the fracture surfaces of the composite indicate that the protein m atrix had penetrated into the particles, to a depth of about 10 mu m, in forming the particle/matrix bond. These results further validate th e use of a materials-science approach to foods.