Abstract
The rheological and microstructural properties were examined of heat-induced gels of thick and thin egg whites obtained from fresh (0-day eggs) and stored eggs (25°C,7-and 14-days eggs). The measurements of textures (hardness, cohesiveness and gumminess) and dynamic viscoelasticity (storage modulus G', loss modulus G" and tan δ=G"/G') of gels prepared by heating at the final temperature of 85°C showed that the gels became softer, more elastic and more sticky with increasing of the storage period, and gels from thick egg white in the 0-and 7-day eggs were slightly softer than ones from the corresponding thin egg white. From the G' values obtained during heating from 20 to 85°C, gelling temperatures were found to increase with storage indicating similar changes between the thick and thin egg whites. The microstructural characteristics of the gels observed with a scanning electron microscope indicated that the spherically shaped structure attached to the network by protein aggregates changed, for stored eggs, to crystal-like structure having larger pore size.
