Prebiotics are defined as non-digestible dietary components that promote the growth of beneficial gut microorganisms. In many cases, however, this capability is not systematically evaluated. Here, we develop a methodology for determining prebiotic-responsive bacteria using the popular dietary supplement inulin. We first identify microbes with a capacity to bind inulin using mesoporous silica nanoparticles functionalized with inulin. 16S rRNA gene amplicon sequencing of sorted cells revealed that the ability to bind inulin was widespread in the microbiota. We further evaluate which taxa are metabolically stimulated by inulin and find that diverse taxa from the phyla Firmicutes and Actinobacteria respond to inulin, and several isolates of these taxa can degrade inulin. Incubation with another prebiotic, xylooligosaccharides (XOS), in contrast, shows a more robust bifidogenic effect. Interestingly, the Coriobacteriia Eggerthella lenta and Gordonibacter urolithinfaciens are indirectly stimulated by the inulin degradation process, expanding our knowledge of inulin-responsive bacteria.

Background: The importance of prebiotics consumption is increasing all over the world due to their beneficial effects on health. Production of better prebiotics from endemic plants raises possibilities to enhance nutritional effects in vulnerable population groups. Fructans derived from Agave Plant have demonstrated their safety and efficacy as prebiotics in animal models. Recently, the safety in humans of two fructans obtained from Agave tequilana (Metlin^® and Metlos^®) was demonstrated. Methods: This study aimed to demonstrate the efficacy as prebiotics of Metlin^® and Metlos^® in newborns of a randomized, double blind, controlled trial with a pilot study design. Biological samples were taken at 20 ± 7 days, and three months of age from healthy babies. Outcomes of efficacy include impact on immune response, serum ferritin, C-reactive protein, bone metabolism, and gut bacteria changes. Results: There were differences statistically significant for the groups of infants fed only with infant formula and with formula enriched with Metlin^® and Metlos^®. Conclusions: Our results support the efficacy of Metlin^® and Metlos^® as prebiotics in humans, and stand the bases to recommend their consumption. Trial Registration: ClinicalTrials.gov, NCT 01251783.

The dry, powdered cladodes of Opuntia ficus-indica are often-used in over-the-counter (OTC) pharmaceutical formulations. Gentle drying techniques, such as lyophilization and vacuum drying are compared with convection drying for the cladodes and also compared with another species of economic importance, Opuntia joconostle. The heteropolysaccharide purified from the mucilage extracted from the dried powders were investigated in their monosaccharide composition (HPAEC-PAD, TLC), mineral and protein content, molecular dimensions (SEC) and fermentability by probiotic bacteria (Bioscreen technique) for evaluation of the prebiotic potential of the mucilage. The heteropolysaccharide is composed of galactose, arabinose, xylose, galacturonic acid and rhamnose. O. ficus-indica includes an additional 13% of glucose coming from an α-glucan. The content of Ca (0.3%) and Mg (0.4%) is relatively low in both species; the content of protein adds up to 1.5% in O. ficus-indica but is significantly lower in O. joconostle with 0.8%. The average molecular mass M_w of the extracted mucilage ranges from 3.7 to 4.7 × 10⁵ g∙mol⁻¹ for both species; only the mucilage from long-time convection drying (C2) delivers a lower average M_w of 2.6 × 10⁵ g∙mol⁻¹, due to partial breakdown of the mucilage matrix. All tested probiotic strains utilized the mucilage to some extent; C2 being the most active, and thus confirms the prebiotic potential of cladode’s powder and its derived products. In general, the molecular dimensions and prebiotic potential are not extremely sensitive to the drying treatment, yet temperature and drying time can modify the cladode’s powder to a profile with better prebiotic characteristics.

The mucilage extracted from the convection-dried cladodes of O. ficus-indica and O. joconostle, two species of economic importance, delivered three fractions after methanol precipitation. Two were composed of high molar mass polysaccharides, and one included water-soluble mono-, di-, and oligosaccharides. The large polysaccharides have a molar mass range of 4.0 × 10³ to 8.0 × 10⁵ g·mol^-1 and are consistently composed of galactose, arabinose, xylose, and rhamnose; however, the content of galacturonic acid was different between both fractions and species. Their fermentability by selected probiotics was relatively low, 11-27 % compared to glucose, and decreased with increasing levels of galacturonic acid in the molecules. In the third fraction, previously unreported oligosaccharides were found. These include simple- and complex-structured galactooligosaccharides with arabinosyl-, xylosyl- and galacturonosyl acid residues. Their fermentability by prebiotic species can be ascribed more to their structural characteristics and monosaccharide composition than their molecular dimensions.