Colloidal Stability and Lipid-Lowering Effects of Fermented Cyclocarya paliurus-Based Tea Beverages

Cyclocarya paliurus polysaccharides (CPP) possess various physiological functions such as lipid-lowering and antioxidant activities. However, as a complex plant-based dispersion system, the interfacial characteristics of fermented C. paliurus beverages often restrict the release of bioefficacy of the active ingredients. This study investigated the impact of particle size on the colloidal stability and lipid-lowering activity of C. paliurus beverages fermented by Lactobacillus plantarum and established an empirical correlation between the two. While the 200–300 mesh fraction showed superior physical stability, the 40–60 mesh fraction was identified as the optimal formulation in this study when balancing ROS indicators. In vivo assays using Caenorhabditis elegans demonstrated that the 40–60 mesh formulation significantly reduced MDA levels and inhibited lipid accumulation, decreasing TG content by 19–46%. Notably, the average diameter of lipid droplets decreased by 38.4%, promoting the conversion of large storage-type droplets to small/medium-sized droplets with high metabolic activity. This study reveals the trade-off between physical dispersibility and bioavailability, providing a theoretical basis for optimizing the interfacial structure of functional plant-based beverages.