In vivo absorption in mice and fecal fermentation by human gut microbiota: impacts on gut microbiota and short-chain fatty acids production.
BACKGROUND Current understanding of the biological activities and metabolism of raffinose remains limited. This study aimed to elucidate its digestive behavior and anti-allergic potential by integrating fluorescence imaging in mice, in vitro digestion simulation, human fecal fermentation, and RBL-2H3 cells detection. RESULTS The results showed that following oral gavage in mice, raffinose was primarily distributed in the gastrointestinal tract and reached the colon within 2-6 h. In addition, raffinose was hardly degraded during in vitro simulated gastric and intestinal digestion. Analysis of human fecal microbiota demonstrated that microbial richness and diversity were lower in food-allergic individuals than in healthy individuals. In the in vitro fermentation system using human fecal samples, raffinose supplementation increased short-chain fatty acid concentrations in the group involving fecal fermentation from healthy volunteers with raffinose. Furthermore, raffinose inhibited the growth of Escherichia-Shigella and Weissella. In the RBL-2H3 cell degranulation model, raffinose promoted cell proliferation, suppressed degranulation, and reduced the release of β-hexosaminidase and histamine, demonstrating its anti-degranulation capacity. CONCLUSION Our results verify that raffinose is indigestible in the upper gastrointestinal tract using a mouse model. It modulates gut microbiota and short-chain fatty acids in in vitro human fecal fermentation systems and produces anti-allergic effects in cell models. These findings provide a foundation for expanding the applications of raffinose in deep processing as a value-added functional product. © 2026 Society of Chemical Industry.