Date pomace polysaccharides-capped selenium nanoparticles: Biosynthesis, optimization, physicochemical characterization, biological activities, stability and gut microbiota modulation

Selenium nanoparticles (Se-NP_S) are recognized for their bioavailability and low toxicity, though their inherent instability limits broader applications. This study explored the biosynthesis and functional properties of selenium nanoparticles (Se-NPS) stabilized with date pomace polysaccharides (MPS-NP_S). The MPS-NP_S characteristics, digestibility and impact on human gut microbiota were investigated. The MPS-NP_S were well-stabilized, spherical particles averaging 65.4 nm in size, with PDI (0.032), zeta potential (–21.07 mV) and notable antioxidant activity (82.7 % DPPH, 68.9 % ABTS, 491.0 µg/mL FRAP, and 961.2 µg/mL TAC at 100 mg/L). They also showed concentration-dependent enzyme inhibition: 86.8 % α-amylase, 53.9 % α-glucosidase, and 42.4 % ACE inhibition at 100 mg/L, along with anticancer effects against Caco-2 (32.3 %) and MCF-7 (11.3 %) at 50 mg/L. MPS-NP_S demonstrated broad antimicrobial activity against E. coli O 157:H7 (84.2 %), S. Typhimurium (82.5 %), S. aureus (77.2 %), and L. monocytogenes (89.24 %) and supported probiotic growth, indicating prebiotic potential. During fecal fermentation, they boosted short-chain fatty acid (SCFA) production and the abundance of SCFA-producing bacteria, including Gemmiger formicilis and Bifidobacterium species. These findings suggest MPS-NP_S as a promising functional ingredient for gut health and dietary supplementation.