Optimizing Foam Properties of Egg White Powder-Based Foam System by Response Surface Methodology

Foam is a thermodynamically unstable multiphase system consisting of a continuous liquid and discontinuous air phases. Therefore, the interfaces between the air and water phases need to be stabilized by surfactant components. For this purpose, egg white proteins are the most widely used interfacial agent in the food sector; however, the foaming properties of egg white powders produced for technological purposes are negatively affected by thermal treatment. Thus, in this study, the impact of process variables such as saponin extract (0.05-0.15%), guar gum (0.1-0.4%), and mixing time (3-9 min) on foaming capacity (FC) and foam stability (FS) was investigated using response surface methodology via Box-Behnken design to enhance the foaming characteristics of protein powders. The analysis of variance results demonstrated that all process parameters had a highly significant effect on the quadratic FC model. However, it was found that the effect of guar gum on the FS model was dominant (P < 0.05). Furthermore, the results showed that increasing saponin content and mixing time, as well as guar gum and mixing time resulted in increased values of FC and FS, respectively. Moreover, Design Expert 13.0 was used as a statistical tool to perform multi-response optimization of both responses via the desirability function approach. The findings indicated that the optimal combination for maximizing responses was at 0.15% saponin content, 0.37% guar gum, and 9 min of mixing time.