Mechanism of enhancing rehydration capacity and foaming property of spray-dried egg white powder by lactic acid fermentation

Spray-dried egg white powder has limited applicability as a raw material in food production due to its deteriorative rehydration capacity. Lactic acid fermentation is a promising technique for protein denaturation and has been widely used in the food industry. In this work, we investigated the effects of 4, 8, and 12-h lactic acid fermentation on protein structure, powder characteristics, rehydration capacity, and foaming property of spraydried egg white powder. Results show that the fermentation treatment significantly reduced the surface hydrophobicity of egg white powder samples, while 8 and 12 h of fermentation significantly increased their zeta potential. During the 12 h of fermentation, the particle size of the powder gradually decreased from 2.59 mu m to 1.69, 1.23, and 0.76 mu m, respectively. Scanning electron microscope result shows the same and also indicates a concave hole structure in fermented egg white powders. These changes in protein molecules result in the significantly improved wettability, dispersibility, and solubility of the powder, thus enhancing its rehydration capacity. The foaming ability and foam stability of egg white powder also significantly improved after fermentation. Furthermore, the fermentation process altered the secondary structure, moisture content, bulk densities, flowability, and color of the powder. This work demonstrates the usefulness of lactic acid fermentation in enhancing the quality of egg white powder. The findings have significant implications for the development of better-quality egg white powder products in the food industry.