Exploring the prebiotic potential of dietary fibre concentrates from artichoke, red pepper, cucumber, and carrot by-products

The agri-food industry exerts a considerable environmental impact while contributing to substantial losses of functional nutrients, particularly dietary fibre. Developing dietary fibre concentrates (DFCs) as novel functional food ingredients offers a dual opportunity: reducing environmental impact and delivering health-promoting prebiotic ingredients. This study evaluated the prebiotic potential of DFCs from artichoke, carrot, cucumber, and red pepper by assessing their impact on targeted gut microbiota composition and short-chain fatty acid (SCFA) production during 48 h of in vitro colonic digestion. All DFCs reduced the Firmicutes/Bacteroidetes ratio from 0.5–0.8 at 24 h to below 0.4 at 48 h, indicating shifts towards microbial profiles favoring fibre degradation. Artichoke DFC induced the most pronounced effect, markedly stimulating Lactobacillus populations (>100-fold at 24 h and 14-fold increase at 48 h), likely linked to its chlorogenic acid and inulin content. Carrot DFC also promoted Lactobacillus spp . growth at 24 h, while both artichoke and carrot DFCs enhanced Bifidobacterium abundance. SCFA analysis revealed acetic acid as the dominant metabolite, with peak concentrations in cucumber (35.85 mM), red pepper (32.18 mM), and carrot (22.85 mM) fermentations at 48 h. Remarkably, artichoke DFC yielded the highest butyric acid concentration (13.30 mM), a key metabolite for colonocyte energy supply and intestinal barrier integrity. These findings establish vegetable-derived DFCs, particularly artichoke and carrot, as promising prebiotic ingredients that can be selectively utilised by microorganisms to confer health benefits, while also highlighting a sustainable strategy to transform agricultural by-products into valuable functional foods ingredients with possible impacts on gut health.