In Vitro Assessment of the Prebiotic Potential of Agave-Derived Carbohydrate Preparations on Lactic Acid Bacteria and Escherichia coli Strains

Prebiotic potential refers to the stimulation of beneficial bacteria over pathogenic strains. This preliminary study evaluated the prebiotic potential of five agave-derived carbohydrate preparations using lactic acid bacteria (LAB) and Escherichia coli (pathogenic) strains. The tested substrates included commercial inulin, commercial agave syrup, artisanal maguey syrup, aqueous and cooked agave extract. Six Lactobacillus strains (Lactobacillus acidophilus, Lacticaseibacillus casei, Lactiplantibacillus plantarum ATCC 8014, Limosilactobacillus reuteri NRRL B-14171, Lactiplantibacillus plantarum NRRL B-4496, and Lacticaseibacillus rhamnosus) were evaluated against E. coli ATCC 43888 and E. coli clinical isolates. Carbohydrate characterization included analyses of total and reducing carbohydrates and thin-layer chromatography (TLC) to assess the degree of polymerization (DP). Prebiotic Index (PI) and Prebiotic Activity Score (PAS) were calculated to determine selective growth stimulation at 24 and 48 h. TLC analysis revealed two distinct groups: high-molecular-weight compounds (aqueous agave extract and commercial inulin), and low-molecular-weight compounds (cooked agave extract, commercial agave syrup, and artisanal maguey syrup). L. reuteri NRRL B-14171 exhibited the highest PI (approaching 2.0) with aqueous agave extract at 24 h. L. rhamnosus demonstrated superior PAS values across all prebiotic sources, while commercial inulin and artisanal maguey syrup showed the most favorable PAS values against clinical E. coli isolates, indicating preferential in vitro growth of LAB over the pathogen. These findings represent preliminary indications of selective carbohydrate utilization by LAB strains under controlled in vitro conditions. Further studies, incorporating digestion resistance, fermentation by complex microbiota, metabolite production, and host-related effects are required before confirming prebiotic functionality.