Comprehensive characterization of the complexes of exopolysaccharides produced by Lactobacillus helveticus MB2-1 with...

Polyphenols have attracted widespread attention owing to their excellent biological activities. However, their low solubility and poor stability limit their bio-accessibility. Numerous studies have demonstrated that the complexation of polysaccharides with polyphenols represents an efficacious strategy to overcome these limitations. Nonetheless, there remains little research exploring the binding effects and underlying mechanisms between exopolysaccharides from lactic acid bacteria and polyphenols. This study aimed to comprehensively explore the structural and functional properties of different complexes prepared using Lactobacillus helveticus MB2-1 exopolysaccharides (LHP) with six kinds of polyphenols.

Six LHP-polyphenol complexes were prepared by non-covalent interactions of LHP with catechin, epigallocatechin gallate (EGCG), quercetin (QU), chlorogenic acid, ferulic acid (FA) and caffeic acid (CAA), and their corresponding binding ratios were 215.80, 223.96, 233.89, 220.35, 198.74 and 214.90 g kg^-1, respectively. Obvious differences were shown in Fourier transform infrared spectra of LHP, polyphenols and their complexes, which confirmed the existence of interactions between them. Moreover, the binding of LHP with polyphenols resulted in obvious changes in molecular weight distribution and aggregation behavior of LHP, significantly enhanced antioxidant activities compared to LHP alone and significantly increased the bio-accessibility of polyphenols as well. Notably, QU and EGCG both have an inhibitory stimulatory effect in the case of LHP binding or forming a mixture, whereas CAA and FA have bidirectional regulation of NO production in macrophages, that is, immunosuppression and immune activation.

The results of the study indicated that the non-covalent complexation of LHP with polyphenols presented fine potentiality in improving the structure and function of food products. © 2025 Society of Chemical Industry.