Comparative effects of non-fermented and Lacticaseibacillus paracasei-fermented pomelo juice on gut microbiota composition and short-chain fatty acid production: An in vitro colonic model

Pomelo juice, especially from the Tubtim Siam cultivar, may offer prebiotic benefits by promoting beneficial gut bacteria. This study evaluated the impact of non-fermented and <i>Lacticaseibacillus paracasei</i> (<i>L. paracasei</i>)-fermented pomelo juice on gut microbiota using an <i>in vitro</i> colonic fermentation model. The <i>L. paracasei</i>-fermented juice significantly increased lactobacilli levels compared to the non-fermented juice, while both treatments similarly suppressed coliforms within 24 h<i>.</i> Microbiota analysis revealed increased richness and significant community shifts in both treatments. Moreover, the fermented juice demonstrated a greater decrease in the <i>Firmicutes</i>/<i>Bacteroidetes</i> ratio, indicating a greater impact on gut metabolism. Fermented juice promoted beneficial bacteria like <i>L. paracasei</i>, <i>Bifidobacterium longum</i>, and <i>Faecalibacterium prauznitzii</i> while inhibiting pathogens. These changes coincided with higher production of short-chain fatty acids (SCFAs), including acetic, propionic, and n-butyric acids. Therefore, fermenting pomelo juice with <i>L. paracasei</i> improves its ability to beneficially influence the gut microbiota, suggesting its potential for gut health enhancement.