Production of stable emulsions using β-glucans extracted from Pleurotus ostreatus to encapsulate oxidizable compounds

The basidiomycete Pleurotus ostreatus is a sustainable food source known to be rich in β-glucans, functional compounds in mushrooms recognized for their numerous health, nutraceutical, and physicochemical properties. The aim of the present study was to extract β-glucans from P. ostreatus powder and to study the feasibility of using the extract to prepare oil-in-water emulsions formulated for the encapsulation of lipophilic antioxidants by spray drying, for example, with an oil droplet size about 2 μm, a dry matter content of 40% w/w, and with a physical stability of at least 2 hrs. Hot-water soluble β-glucans fraction was extracted from P. ostreatus powder following a method adapted from literature. Emulsions were prepared by rotor-stator homogenization using maltodextrin as wall material, β-glucans extract as emulsifier, and commercial sunflower oil as a model for lipophilic active compounds. The emulsion stability was estimated from the evolution over time of the oil droplet size distribution measured by laser light diffraction and experimental data were investigated using one-way ANOVA. Extracts containing up to 27% w/w water-soluble β-glucans were produced. Physically stable mono-modal emulsions were obtained when maltodextrin/ β-glucans weight ratio was lower than about 500 to avoid depletion and β-glucans/oil weight ratio was more than 0.014 to stabilize oil droplets. The usage of emulsifiers made-up by polymeric constituents with inherent bioactivity, such as mushroom β-glucans, could be a sustainable and healthy alternative to common emulsifiers.