High-Pressure Homogenization Modifies the Structure of Pediococcus acidilactici S1 Exopolysaccharide and Enhances Its...

Bile salts (BSs) binding capacity plays a crucial role in cholesterol reduction. This study investigated the enhancement of BSs binding capacity and structural characteristics of Pediococcus acidilactici S1 exopolysaccharide (EPS, designated S1-D1N1) through high-pressure homogenization (HPH) modification optimized using response surface methodology (RSM). The optimal modification parameters were determined to be 60 mg/mL S1-D1N1 concentration, 40 MPa pressure, and 3 homogenization cycles. Under these conditions, the modified polysaccharide (H-S1-D1N1) demonstrated significantly improved BSs binding capacities. Structural and compositional analyses revealed that HPH induced substantial alterations in S1-D1N1. The total carbohydrate content slightly decreased from 94.80% to 90.40%, while high-performance anion-exchange chromatography (HPAEC) analysis showed a significant increase in mannose content (Man, from 77.13% to 84.38%) with corresponding decreases in glucose (Glc) and galactose (Gal). Scanning electron microscopy (SEM) observations indicated that H-S1-D1N1 transformed from an irregular lamellar structure into smoother, thinner, and more compact flake-like architectures. Fourier-transform infrared spectroscopy (FT-IR) suggested reduced hydrogen bonding and increased exposure of hydrophobic groups. Methylation analysis further confirmed structural rearrangements in glycosidic linkages. Molecular docking simulations identified Man residues as the primary binding sites for sodium cholate, with interactions dominated by hydrogen bonds and van der Waals forces. The remarkable enhancement in BSs binding capacity can be attributed to the combined effects of increased Man content, structural reorganization, and exposure of active functional groups induced by HPH modification. These findings provide valuable insights into the structure-function relationship of HPH-modified exopolysaccharides (EPSs) and suggest that H-S1-D1N1 could serve as a promising functional ingredient with enhanced cholesterol-lowering properties. PRACTICAL APPLICATIONS: This research shows that a natural carbohydrate from food-grade bacteria can be made more effective at binding bile salts, a key process for reducing cholesterol, through a simple physical processing method. This improved product has the potential to be developed into a functional food ingredient, such as in yogurts or dietary supplements, to help manage cholesterol levels in a natural way.