Viscoelastic properties, microstructure and stability of high-oleic O/W emulsions stabilised by crayfish protein concentrate and xanthan gum

This work is focused on the evaluation of crayfish protein concentrates in the formation and stabilization of low-fatty and high-oleic emulsions, as a function of pH, with the presence of a polysaccharide (Xanthan Gum) as stabilizer. Interfacial O/W characterisation is carried out in order to determine the protein concentration in which the saturation of the interface takes place, protein adsorption kinetics, as well as to predict the emulsions stability. Emulsion characterization is based on rheological characterization and the microstructure is evaluated through droplet size distributions (DSD) analysis and Confocal Laser Scanning Microscopy (CLSM). In addition, backscattering measurements are relevant to describe the destabilization mechanism Results indicate that emulsion ability and stability are highly sensitive to the pH value. In our conditions, the best emulsifying properties corresponds to emulsion carried out at pH 3, which shows unflocculated unimodal distributions, remaining unaltered in size over 2 months. However, the occurrence of coalescence takes place at pH 5 and 8. In addition, results support the key role of the interaction between proteins and polysaccharide (Xanthan gum, XG), which form a gel-like network.