LAUSR

Abstract Inulin is a prebiotic ingredient that is being increasingly used in food formulations as fat replacer. Even if no significant surface activity has been reported for this natural polysaccharide, it can be used as ingredient in Oil in Water (O/W) emulsions that would benefit from its potential thickening effect of the continuous phase. In this manuscript, a well-characterized milk protein (β-lactoglobulin) was used at 0.5 % wt. content as emulsifier, while inulin was included in different concentrations from 0 to 10 % wt., in pressure-homogenized O/W emulsions (5/95). Zeta-potential measurements suggest the absence of important interactions between the protein and the polysaccharide in the continuous phase, observing an increase in the viscoelastic properties and viscosity of these pseudoplastic systems as inulin content is higher. In spite of no detecting any interfacial activity for inulin, its presence seems to favor the kinetics of protein adsorption, which might be attributed mainly to a thermodynamical incompatibility phenomena between both biopolymers. At high enough inulin content, the potential existence of protein-polysaccharide complexes become more probable, which may hinder protein adsorption, leading to a diminution of the steady-state interfacial pressure and an important reduction in interfacial dilatational modulus. The study of the droplet size distribution of the emulsions along storage time reveal how the bimodal distributions obtained keep constant, pointing out the stability of the emulsions prepared, a fact that is further supported by backscattering measurements along time. Emulsions including a prebiotic like inulin have an enormous potential in the food industry (e.g. smoothies).