Effect of different hydrophobic soybean isolated peptides and their zinc complexes on the growth and fermentation of Lactobacillus bulgaricus

This study was conducted to investigate the effects of the addition of different hydrophobic peptides and their zinc complexes on the growth and fermentation of lactic acid bacteria (LAB). According to the results of peptide surface hydrophobicity assays, three distinct hydrophobic peptides were isolated from soybean peptides (SP). The UV and FTIR measurements revealed that the peptide-zinc complexes (SPZnC) were successfully prepared. The LAB group supplemented with ZnSPC exhibited significantly higher biomass, viable bacteria count, acid production capacity and glucose consumption compared to the LAB group supplemented with other components such as organic zinc, inorganic zinc and peptide. Among these supplements, Zn-MHP demonstrated the most pronounced promotion of Lactobacillus growth and fermentation. Furthermore, additional fermentation experiments conducted on curdled fermented milk demonstrated that the inclusion of Zn-MHP resulted in improved quality and reduced fermentation time. These findings suggest that Zn-MHP possesses the ability to enhance the physiological function of LAB.