Impact of phenolic-rich feijoa (Acca sellowiana 'Kakariki') peel extract on the mucin-adhesive properties of selected probiotic strains

This study examines the impact of phenolic-rich Acca sellowiana 'Kakariki' peel (KKPL) extract on the mucin-adhesive properties of Limosilactobacillus reuteri DPC16, compared to the commercial strain Lacticaseibacillus paracasei 21712. The study characterized the cell surface properties, adhesion ability, and pathogen-interference interactions of these lactic acid bacteria on porcine gastric mucin in vitro. Results showed that L. reuteri DPC16 exhibited significantly higher hydrophobicity (56.94%), auto-aggregation (60.59%), and co-aggregation with pathogens (58.62%) in the presence of KKPL extract, as confirmed by scanning electron microscopy (SEM). KKPL extract significantly enhanced (p < 0.05) Lactobacillus’ adhesion to porcine mucin. Moreover, L. reuteri DPC16 demonstrated stronger competitive inhibition, reducing Bacillus cereus and Escherichia coli colonization by 74.30% and 65.80%, respectively.

The phenolic compounds in KKPL extract appeared to modulate probiotic surface properties, enhancing adhesion and competitive exclusion of pathogens at epithelial cell receptors. CLSM further confirmed increased mucosal adhesion, showing denser and more extensive Lactobacillus attachment in the presence of phenolic compounds. These findings highlight KKPL extract as a potential natural enhancer of probiotic efficacy, with potential applications in gastrointestinal health and probiotic formulations.