Prebiotic Effect of Agave Fructans and Mixtures of Different Degrees of Polymerization from Agave angustifolia Haw

Agave fructans are complex and highly branched molecules, which cannot be digested in the upper gastrointestinal tract. As a result, when they reach the large intestine, they serve as fermentative substrates for bacterial growth. Previous reports have shown that fructans of the inulin-type, through both in vitro and in vivo assessments, are effective prebiotics, increasing the content of bifidobacteria and lactobacilli in the gut and, consequently, inhibiting the growth of pathogenic bacteria. Oaxaca has the largest diversity of Agave species in Mexico. Agave angustifolia contains high amount of fructans with potential health benefit for humans. The aim of this work was to investigate the growth rate of six bifidobacteria and four lactobacilli strains when fructans and mixtures with different degrees of polymerization (DP) from A. angustifolia were used as an energy source. We observed that agave fructans stimulated the growth of bifidobacteria and lactobacilli more efficiently (2-fold) that commercial inulins. Bacterial growth, pH drop and SCFA’s production, mainly acetate, were different among strains; while in vitro fermentation revealed that mixtures of different degrees of polymerization and short-DP (< 10) fructans were highly fermented. Biomass and pH drop were larger when the substrate contained mostly short-DP fructans. In conclusion, the presence in the mixtures of short-DP fructans, influenced significantly the rate of fermentation by the probiotic bacteria. _____________________________________________________________________________________________________________