Effect of agave fructans on xanthan rheology: Impact on sodium caseinate emulsion properties.

Abstract

The influence of agave fructans (AF) (1-10%) and xanthan (from 0.03% to 0.25%) in combination with sodium caseinate (SC) at 1% on the rheological and physicochemical properties of aqueous phases and emulsions was evaluated. Steady-state flow behavior, particle size distribution, and stability studies were used to characterize the systems. The aqueous systems displayed the shear-thinning behavior characteristic of xanthan solutions; however, this behavior was modified by the presence of SC and AF due to interactions between AF-SC and AF-xanthan based on predominant hydrogen bonding because of the hydroxyl groups on AF. In emulsions, an increase in viscosity due to the effect of the AF concentration reflects a probable association of fructan aggregates on the surface of SC particles that reinforce the interfacial layer of SC, while xanthan contributes to an increase in the viscosity of the continuous phase, which effectively prevents coalescence and floc formation even at higher concentrations, despite the possible existence of a depletion flocculation effect attenuated by the interaction between AF-SC and AF-xanthan. PRACTICAL APPLICATION: These results can be of use, in an important way, in the design of stable functional emulsions in which there is an application for agave fructans recognized as dietary fiber, also considering their peculiar way of interacting with xanthan favoring its stabilizing functionality.