Rheological properties of liquid egg products (LEPS)

Rheological properties were determined at 4 degrees C (refrigerated temperature), 25 degrees C (room temperature), 60 degrees C (pasteurization temperature) for liquid whole egg (LWE) and liquid egg yolk (LEY) and 4, 25, 55.6 degrees C for liquid egg white (LEW) by using concentric cylinder viscometer. The shear rate range was 8 to 53.7 s(-1) for LEW and LWE, and 1 to 34 s(-1) for LEY. Selected physical properties (e.g., density) of LEPs were studied at broad range of temperatures from 4 degrees C to 60 degrees C. All liquid egg products (LEPs) exhibited mildly shear thinning (pseudoplastic) behavior. Experimental data of LWE and LEW successfully fitted Herschel-Bulkley model, LEY data were well described by power law model. LEW and LWE showed thixotropy and time-dependency at their pasteurization temperatures (55.6 degrees C for LEW, 60 degrees C for LWE) and considered being time-independent below these temperatures. LEY exhibited time-dependent behavior at 4 degrees C and 60 degrees C. But its rheological behavior showed no thixotropy and time-dependency at room temperature. The density of all three products decreased with increasing temperature. Density data were correlated by polynomial models (r(2) > 0.99).