Effect of the lupin protein/surfactant ratio on the flow and textural properties of oil-in-water emulsions.

The influence of different surfactant/lupin protein ratio on the shear-flow and texture properties of oil-in-water emulsions was investigated in this work in order to find a synergistic effect between both types of emulsifier s. With this aim, texture, steady-shear flow and droplet size measurements were carried out. Different surfactants (Tween 20 and three sucrose esters) showing different phase behaviour in water solution were studied. From the experimental results it can be concluded that emulsions stabilised by mixt ures of both, low- and high-molecular-weight emulsifiers, show lower values of steady-state viscosity and textural parameters than those found when lu pin protein was the only emulsifier used, in spite of a higher average drop let size. The evolution of emulsion textural and flow parameters with the c omposition of the mixture used as emulsifier can be explained on the basis of the phase behaviour of the low-molecular-weight emulsifier, modification s on the composition at the interface and hydrophobic interactions between both type of emulsifiers.