Stabilization of oil-in-water emulsions with a mushroom (Agaricus bisporus) by-product

Abstract

[eng] A concentrate of mushroom (Agaricus bisporus) by-products (MC), mainly composed of polysaccharides and proteins, was used as an emulsifier (1.5-7.5% w/w) in oil-in-water emulsions. An emulsion stabilized with Tween®20 was used as control. MC (5 and 7.5% w/w) increased the emulsion viscosity and promoted shear-thinning behaviour. Median droplet diameters of 5 and 7.5% w/w MC emulsions (d50 ~2.8 and ~2.1 μm) were similar to that of control but larger (p < 0.05) in 1.5 and 3% w/w MC emulsions (d50 ~5.2 and ~3.4 μm) which also presented flocculation. Emulsions with 5 and 7.5% w/w MC were more stable against droplet size variation than the control. The backscattering profiles showed less droplet migration with MC addition (5 and 7.5% w/w). Stability promoted by MC was due to viscosity increase, steric hindrance, and probably Pickering effect and not to electrostatic forces according to the Z-potential. MC addition promoted perceptible colour changes in the emulsions.