Egg white fermentation by lactic acid bacteria: Effects on gel characteristics and preliminary investigation of suitable genera

There were few researches to investigate the suitable lactic acid bacteria (LAB) genera for long time fermentation of on egg white (EW). This study aimed to investigate effect of complex LAB fermentation on protein structure and gel properties of EW, and identify LAB genera suitable for EW environment. Therefore, high-throughput sequencing, fluorescence spectroscopy, texture profile analysis, and scanning electron microscopy (SEM) were performed. Sequencing results showed Bifidobacterium and Lactiplantibacillus were the main LAB genera, suggesting their potential to ferment EW for long time. During fermentation, the pH decreased from 9.20 to 8.91 in EW, and from 9.25 to 8.82 in diluted egg white (DEW). Surface hydrophobicity of EW and DEW protein increased from 6.60% to 11.70% and 3.18%-30.98% (p < 0.05), respectively. Gel hardness and springiness of fermented DEW in the presence of glucose increased significantly 16.64% and 2.46% at 12 h, 18.02% and 1.94% at 24 h, respectively. SEM results showed that protein aggregates distributed more evenly in dilution and glucose supplemented EW gel. The lower pH, higher surface hydrophobicity, and better texture characteristics indicated that the supplement of glucose and the dilution of EW were helpful for the progress of fermentation. In conclusion, Bifidobacterium and Lactiplantibacillus genera were seemed to adapt well in EW, and the dilution as well as glucose supplement was verified effectively to promote the LAB fermentation process. These findings can serve as a reference for the development of fermented EW products and provide guidance for further processing of eggs.