Mechanism study on enhanced foaming properties of individual albumen proteins by Lactobacillus fermentation

Our recent research showed that moderate Lactobacillus fermentation endowed egg white with stronger foaming properties. But the individual contribution of albumen proteins and the relative mechanisms during the process were still not clear. In this study, three major egg white proteins (ovalbumin, ovomucin and ovomucoid) were singly fermented by multiple Lactobacillus (Lactobacillus delbruekii ssp. bulgaricus, Lactobacillus acidophilus, Streptococcus thermophilus and Bifidobacterium animalis) for 0, 3, 6 and 9 h, and the surface activity, degradation, apparent viscosity and foaming properties were investigated. For ovalbumin, the surface hydrophobicity largely increased at 3 h and then began to decrease; combined with the gradual degradation by protease, the foaming ability of ovalbumin significantly increased at 3 h and then decreased at 6 and 9 h of fermentation. The fermented ovomucin and ovomucoid possessed an improved surface characteristics and appropriate apparent viscosity; correspondingly, the both proteins exhibited the enhanced foaming ability and stability after fermentation. This work revealed the molecular mechanism behind Lactobacillus fermentation treatment increased foaming properties of egg white, and provided basic information on the application of fermentation approach in improving functionalities of egg white in industry.