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 micrometer), leading to enhanced firmness and storage stability of the Pickering emulsions.

Delivery of probiotics and enzymes in self-assemblies of lipids and biopolymers based on colloidal principles

“…Probiotic lactic acid bacteria can be incorporated into food structures and have the dual role of being a functional part of the food structure as well as delivering the probiotic function of the bacteria. Several studies have focused on Pickering emulsions stabilized by bacteria adhering to the oil/water interface using natural UM bacteria (Firoozmand and Rousseau, 2016;Muhammed et al, 2023) and chemically modified bacteria (Jiang et al, 2019;Jiang et al, 2021). The emulsions exhibited large emulsions droplets of 10-100 μm, which was one to two orders of magnitude larger than the size of bacteria (~1 µm).…”

“…Mayonnaise-like emulsions were produced using food grade, Streptococcus thermophilus with a high internal oil phase load exceeding 40% (Firoozmand and Rousseau, 2016). MCT oil in water emulsions were produced using a selection of 31 naturally hydrophobic lactobacillus bacteria (Muhammed et al, 2023), as well as enzymatically treated LGG and LBD bacteria (Jiang et al, 2021). The highly hydrophobic LGG bacteria modified by laurylchloride exhibited the surprising ability to promote the formation of W/O/W double emulsions (Figures 3A-C using a simple one-step procedure (Jiang et al, 2021).…”