Lactobacillus plantarum-loaded pomelo pith matrix gel beads: Fabrication, characterization, and regulatory effects on human gut microbiota

Encapsulation technology is a crucial method for enhancing probiotic survival through gastrointestinal digestion. This study utilized ethanol-modified pomelo pith matrix (PP) passed through 40-, 100-, and 200-mesh sieves (PP-40, PP-60, and PP-100) and sodium alginate and/or fructooligosaccharide (FOS) to create gel beads for encapsulating Lactobacillus plantarum (LP). The effects of these gel beads on probiotic loading, protection, release behavior, and gut microbiota regulation were investigated. The 100-mesh pomelo pith matrix increased the specific surface area and pore volume, enabling uniform probiotic distribution within gel beads and supporting controlled swelling behavior. Pomelo pith matrix gel beads, particularly PP-LP-100, exhibited superior acid tolerance, controlled release, higher loading capacity, improved survival during simulated digestion, and greater protection during pasteurization and storage for Lactobacillus plantarum . Incorporating FOS into pomelo pith matrix gel beads boosted microbial fermentation and diversity, leading to increased gas production, total SCFA levels, and butyric acid content. The gel beads containing FOS increased the abundance of Bifidobacterium , Blautia , Faecalibacterium , and Ruminococcus , while PP-LP gel beads enriched Bacteroides and Lactobacillus . This study provides a foundation for developing advanced probiotic formulations with improved stability and controlled release.