Kinetics of Heat Coagulation of Egg Albumin Determined by Water Binding and Rheological Measurements

Dynamic testing of heat coagulated egg albumin revealed that phase angle, a measure of the fluidity of a viscoelastic material, exhibits a first order change during heating in a similar manner as the changes in the spin-lattice relaxation time (T1) of water protons measured by a pulsed nuclear magnetic resonance instrument. The absolute modulus, on the other hand, which is an index of the elastic properties exhibited a zero order change in a similar manner as the development of gel strength measured by constant rate penetrometry using an Instron universal testing instrument. Arrhenius activation energy of 29 kcal/mole for the phase angle and 38.9 kcal/mole for the absolute modulus indicate that the process of protein-water interaction to immobilize water within the gel and that of protein-protein interaction to form the solid gel network occur simultaneously during heating, but they proceed by different mechanisms with the latter process showing greater heat sensitivity.