Rheological characterization of dispersions and emulsions used in the preparation of microcapsules obtained by interfacial polymerization containing Lactobacillus sp.

The main objectives of this work were the rheological characterization of dispersions and emulsions used in the microcapsules preparation and the microcapsules obtain from gum arabic (A), gellan gum (G) and mesquite seed gum (M) to keep lactic bacteria (Lactobacillus sp.) viable using the interfacial polymerization technique (IP). Dispersions of A, G and M were prepared to obtain microcapsules, as well as binary mixtures of gum arabic and gellan gum (AG), gum arabic and mesquite seed gum (AM) and gellan gum and mesquite seed gum (GM); these dispersions exhibited a shear thinning non-Newtonian behavior. The emulsions were prepared using sunflower oil as the oily phase in a 1:1, 1:3 and 1:5 ratio with the disperse phase; the oily phase was added with Span 85 (surfactant) at 1, 2 and 3% concentrations; the emulsions A (1:5 and 3% Span 85) and GM (1:5 and 2% Span 85) showed higher viscosity and stability. Microcapsules were obtained using 0.05 mol L^-1 glutaraldehyde (crosslinking agent) with a reaction time of 3 min. The mean diameter of the microcapsules obtained was 30.17, 16.86 and 10.34 μm according to the AG, AM and GM mixtures, respectively. In the AG and AM dispersions, the microcapsules diameters became larger as the viscosity increased. The microorganism microencapsulates using gum arabic, gellan gum, and mesquite seed gum, was possible. The highest viability (46.7%) of Lactobacillus sp. was obtained with the GM mixture.