Increasing accumulation of microplastics (MPS) in the human body poses potential health risks, such as chronic inflammation and intestinal injury and dysbacteriosis. Treatment to mitigate MPS’s injuries are urgent. This study aimed to investigate the effects of tender coconut water-based postbiotics (POS) on amelioration of lipopolysaccharide (LPS)-stimulated inflammation in THP-1 macrophages and MPS-induced physiological damage in mice. Firstly, the anti-inflammatory activity in vitro was evaluated by measuring the mRNA and protein expression of cytokines and mediators via qPCR, western blotting and ELISA. The metabolites profile was characterized by non-targeted metabolomics. MPS-exposure mice was utilized to verify the effects of POS on protecting from inflammation, intestinal injury and dysbacteriosis via ELISA, fluorescence histopathology, metagenomics, as well as short chain fatty acids (SCFAs) contents. Both POS and unfermented coconut water (CW) showed inhibition on Nuclear Factor-kappa B (NF-κB) and Mitogen-Activated Protein Kinase (MAPK) activation, while POS had a greater inhibitory effect. POS showed higher anti-inflammatory activity by significantly regulating mediators and cytokines’ gene transcription (Nrf2, HO-1, TNF-α, IL-6, IL1β, and IL-10), and secretion (IL-1β). Non-targeted metabolomics analysis showed that POS and CW were significantly separated in diversity, revealing the characteristic metabolites of POS and differential metabolic pathways. Animal study results revealed that POS rather than CW attenuated MPS-induced damage in mice by significantly decreasing aspartate transaminase, alanine aminotransferase, and pro-inflammatory factors, increasing Claudin-1 and Occludin expression, goblet cell numbers, gut microbiota richness and abundances, and butyric acid contents. These results provided a potential use of POS in MPS-induced damage.

Four strains of lactic acid bacteria (LAB) isolated from diverse sources were used to ferment guava juice, revealing strain-specific characteristics. Systematic analysis revealed LAB fermentation significantly altered physicochemical properties, bioactive compounds, and metabolic profiles. Lactobacillus plantarum strains notably increased organic acids, polyphenols and flavonoids while reducing sugars in fermented guava juice (FGJ), enhancing its antioxidant capacity and α-glucosidase inhibitory activity. Sensory evaluation and flavoromics analysis identified 55 distinct volatile metabolites that collectively improved juice flavor profiles through increased beneficial flavor compounds (acetoin and acetophenone), and decreased off-flavor substances (caryophyllene and humulene). Non-targeted metabolomics revealed 289 significantly altered metabolites primarily enriched in amino acid metabolism (e.g., DL-glutamate and indolelactic acid) and lipid oxidation pathways (e.g., 6-hydroxyhexanoic acid and dihydroxyacetone), which correlated with both flavor enhancement and antioxidant accumulation. These results demonstrated LAB reshaped guava juice metabolism at both volatile and non-volatile levels, as well as established a theoretical foundation for developing FGJ as a novel functional beverage with health-promoting properties.