Preserving Probiotic Viability to Support Microbiota-SCFA Function: A Low-Water-Activity Five-Strain Synbiotic Formulation

A fermentation-oriented synbiotic has two immediate formulation requirements: the probiotic cells must remain viable during storage, and enough cells must survive gastrointestinal exposure to encounter fermentable substrate. We characterized a 3.0-g BALIMONT five-strain powder produced by separate premixing and low-humidity post-blending. Water activity was 0.21, moisture 4.3% and 12-month viable-cell retention 69.8%. Simulated-digestion survival was 60.5%, compared with 46.2% after direct blending and 44.6% after premature contact with sensitive components. In the in vitro fermentation model, relative SCFA production was normalized to 1.00 for the optimized powder and measured 0.66 and 0.68 for the two comparators. Human trials of inulin-type fructans, FOS, resistant fermentable substrates and L. plantarum-containing interventions show reproducible changes in selected microbiota features, whereas fecal SCFA concentrations and metabolic outcomes vary with substrate and host phenotype. Multispecies synbiotic trials demonstrate that human SCFA endpoints can change under defined conditions. The formulation data therefore establish a delivery-controlled platform for direct studies that measure strain persistence, community composition, fecal and circulating SCFAs and related host responses together.