Comparison of Different Mechanical Methods for the Modification of the Egg White Protein Ovomucin,Part A: Physical Effects

Egg white (EW) is required to be reduced in viscosity and particle size prior to chromatographic fractionation of single EW proteins. This study reports on an assessment of various shear devices for this purpose. Evaluation criteria for the head-to-head comparison of high-pressure homogenization, colloid mill, and toothed disc dispersing machine treatment were the achieved viscosity reduction as well as the network diminution, determined by particle size measurements. It was shown that each of the devices was able to decrease the viscosity by a reduction of fibril size. However, only the high-pressure homogenizer fulfills the requirement to disintegrate the fibrils sufficiently, so that they can be filtered through membranes with a pore size of 0.45 μm, which is indispensable for chromatographic fractionations. Generally, the achieved viscosities decreased with increasing energy input, independently of the specific shear forces resulting from the applied device. Otherwise, there was no direct correlation between the energy density and the extent of fibril destruction, indicating that the kind of energy depending on the respective device with its specific destruction mechanism was not decisive. To sum up, this study provides profound knowledge concerning the effects on the EW structure that result from different mechanical forces.