The effect of chitosan nanoparticles on the rheo-viscoelastic properties and lipid digestibility of oil/vinegar mixtures (vinaigrettes)

The role of chitosan nanoparticles on the rheological behaviour, antioxidant properties and lipid digestibility of vinaigrettes was investigated in comparison with a protonated chitosan polymer. Nanoparticles were produced using different concentrations of tripolyphosphate (TPP) and acetic acid. The lower ionic concentrations were used to encapsulate a fish protein hydrolysate. Rotatory tests produced shear-thinning behaviour in the different nanoparticle suspensions. The vinaigrettes with addition of both chitosan and nanoparticles exhibited a stationary shear-thinning flow with viscoelastic characteristics of weak gels. The presence of chitosan nanoparticles in the emulsified oil phase produced a three-dimensional network with higher energy stability in the case of hydrolysate-loaded nanoparticles. Both chitosan and chitosan nanoparticles increased the radical scavenging capacity of vinaigrettes, but not the ferric ion reducing power. Addition of empty or hydrolysate-loaded nanoparticles reduced lipid digestion in vinaigrettes to a greater extent than chitosan (≈45% with nanoparticles; 33% with chitosan).