Impact of Lactobacillus fermentation on mung bean Protein's binding to beany flavor: Mechanisms and structural changes

The combination of mung bean protein (MBP) and beany flavor compounds results in an unpleasant soy-like flavor. This study investigated the binding mechanism between MBP and beany flavor substances. The effect of structural changes in MBP during Lactobacillus fermentation on the interaction with flavor compounds was analyzed. The study also examined the changes in volatile flavor compounds. The results showed that the binding constants of MBP with nonanal, hexanal, decanal, and hexanol are all above 104 M- 1.S- 1, with the number of binding sites ranging from 2.12 to 5.29. Thermodynamic parameters demonstrated that hydrogen bonding and hydrophobic interactions play a dominant role in the binding of MBP to beany flavor compounds. Structural changes in MBP during Lactobacillus fermentation were found to weaken its binding capacity with beany flavor compounds, as evidenced by a reduction in the amounts of 7S and 11S subunit proteins and a significant increase in-SH and-S-S- content. Moreover, there was a transition from alpha-helix and beta-sheet to beta-turn and irregular coil structures. Lactobacillus plantarum LP90 eliminated 92.57% of beany-flavor aldehydes and alcohols after 24 h of fermentation. This study provides a theoretical foundation for understanding the binding mechanism between MBP and beany flavor compounds.