Biopolymers phase separation monitored by a plasmonic sensorExperimental.Most BLG/AG mixed dispersions were prepared by adding AG to BLG dispersion at a protein (Pr)  polysaccharide (Pol) weight ratio of 2  1, the ratio corresponding to the maximum strength of interactions between BLG and AG.24The blend was gently stirred for 30 min at room temperature. The pH of the blend was at 7.30 at the end of the stirring period. Mixed dispersions were filtered through a 0.22 μm syringe filter (Millipore, Bedford, USA). 0.11 wt% of glucono-δ-lactone (GDL) was then added to the mixed dispersion and dissolved under stirring for 5 min. In the aqueous medium, GDL is hydrolyzed until equilibrium is reached between gluconic acid and GDL. Gluconic acid releases protons and gluconate in the medium. This proton release leads to a slow medium acidification. At a given pH, aliquots were taken from dispersions and deposited on the surface of nanopatterned silver nanoparticles in order to study the binding be

We report here a real-time study of interactions induced phase separation between β-lactoglobulin (BLG) and Acacia gum (AG) by analyzing the localized surface plasmon resonance of silver nanoparticles. We showed that the binding of BLG to AG is accompanied by refractive index changes, in relation with optical properties and structural changes of the complexes formed. [ABSTRACT FROM AUTHOR]