Comparison of non-thermally extracted polysaccharides from fresh wolfberry with conventionally extracted...

Lycium barbarum polysaccharides (LBPs) are important bioactive constituents of wolfberry, but polysaccharides prepared directly from fresh wolfberry under non-thermal conditions remain insufficiently characterized. This study developed a non-thermal extraction strategy to obtain polysaccharides from fresh wolfberry (FLBPs) and compared them with polysaccharides conventionally extracted from dried wolfberry (DLBPs). By adjusting the relative density of pulp to 1.06 and applying an 85% alcohol precipitation, FLBPs were successfully prepared without heating. FLBPs and DLBPs showed comparable total carbohydrate and protein contents, whereas DLBPs contained significantly more bound phenolics (p < 0.001). The two crude polysaccharides differed in molecular-weight distribution, monosaccharide composition, morphology, Congo red response, particle size, zeta potential, apparent viscosity, and cellular bioactivities. Compared with DLBPs, FLBPs displayed lower bound phenolic content, a narrower molecular weight distribution, stronger cytoprotective activity against H2O2-induced oxidative stress in HepG2 cells, and less induction of NO release in RAW264.7 macrophages. These findings indicate that non-thermally extracted FLBPs can serve as a fresh-material reference for evaluating preparation-associated differences in wolfberry polysaccharides and provide clues for future studies on the roles of drying, extraction, and associated components in shaping the quality of LBPs.