Beneficial effect of oat-based postbiotics produced through capsule or free-cell fermentation on lipopolysaccharide activated intestinal cells

The aim of this study was to design an innovative oat fermentation process using capsules to produce postbiotics with anti-inflammatory and antioxidant potential. Capsule fermentation led to higher bacterial growth (3.30*10 9 CFU/mL) and lactic acid production (20.49 mg/mL), compared to traditional free-cell fermentation (4.73*10 8 CFU/mL and 9.08 mg/mL, respectively), along with increased cell and product yields. The dried postbiotics were also subjected to in-vitro digestion, mimicking the gastrointestinal one. A functional characterization of the four postbiotics, undigested and digested postbiotics from both capsule and free-cell fermentation, was performed using the HCT116 colon cell line. All four products prevented LPS- induced activation of the inflammatory pathway, protein oxidative damage, and impaired glutathione reductase activity, with digested postbiotics being more effective than undigested ones. These findings demonstrate that the capsule-based postbiotic is a promising candidate as a functional food with potential applications in nutraceuticals, animal feeding, and cosmetics. • Capsule optimizes oat fermentation with high yields and improved kinetic parameters. • Oat postbiotics from free cell or capsule fermentation exert anti-inflammatory effect. • Simulated digestion of postbiotics increases the content of antioxidant metabolites. • Postbiotics from capsules reduce more oxidative stress compared to those from cells.