Colloid-chemical properties of aqueous propolis dispersion prepared by the solvent diffusion method

Abstract

Mixing an alcoholic extract of propolis with distilled water or aqueous solution, which model seawater composition, give rise to aqueous dispersions with or without emulsifier. High dispersion stability is attained at hydrophylic-lipophylic balance equaled 13.9 using sorbitan oleate and polyoxyethylene sorbitan monooleate (Polysorbate-80) as a binary emulsifier. The initial particle size of dispersions is almost identical regardless of the presence of the emulsifier or water salinity. However, in the latter case a dispersion with essentially narrow size distribution is formed and, as a result, the dispersion is more resistant to coagulation and phase separation. Apparently, the main contribution to the stability of the aqueous propolis dispersion is made by the structural-mechanical barrier, which is formed by a thick adsorption layer of the hydrated nonionic surfactant