Ex-LactobacillusStrains with Intrinsic Propensity to Stabilize Pickering Oil-in-Water Emulsions

Abstract Knowledge of surface characteristics is a major step in the evaluation of bacterial cells for potential use as Pickering emulsion stabilizers. Here, the cell surface characteristics of 31 strains of the ex- Lactobacillus genus were studied with the aim of evaluating their intrinsic abilities to serve as Pickering stabilizers of oil-in-water emulsions. About 77.42% of the tested strains demonstrated relatively highly negative zeta potential (-43.76 mV ≤ zeta potential ≤ -19.23 mV), while ∼58% of the strains demonstrated high cell surface hydrophobicity (microbial adhesion to hexadecane or MATH ≥ 30%). By combining these findings, four different cell surface features were defined (I, II, II and IV). Strains mainly demonstrated the type I surface feature (∼45%), with most expressing strongly negative zeta potential and high surface hydrophobicity (zeta potential < -15 mV and MATH ≥ 30%, respectively). It appeared that the abundance of negative charge on the surfaces of ex- Lactobacillus cells positively influences surface hydrophobicity. Assessment of intrinsic Pickering stabilization potential using 12 selected strains indicated that four strains showed profound droplet size stability. At least one strain was observed to have natural propensity to form relativley compact and small emulsion droplets (63±3 µm), leading to enhanced firmness and storage stability of the Pickering emulsions.