The Effect of pH and Concentration on the Textural and Rheological Properties of Egg Albumin Foams

Abstract

The effect of different concentrations (i.e. 0.1% - 1%) and pH (7.0 and 4.0) on the textural/physical and rheological properties of egg albumin foams was investigated. The findings indicated that the stability and overrun of the foams were higher in the case of the foams made at pH = 4.0 and with the highest concentration of egg albumin (1%). The apparent viscosity of the albumin solution was significantly (p<0.05) higher at pH = 4.0 and in the presence of the higher concentrations of egg albumin (0.5% - 1%). All of the rheological parameters in amplitude sweep test indicated a weak structure of the foam made at pH = 7.0 and in the presence of a low concentration of egg albumin (0.1%). Regardless of the pH, the values for tan (δ) in the frequency sweep test indicated a weak biopolymer foam structure in the case of all samples. Yield stress was greater in the sample manufactured at pH = 4.0. Overall, the findings suggested that both protein concentration and pH had substantial effects on the rheological and physical properties of egg albumin foams.