Effect of sodium alginate incorporation procedure on the physicochemical properties of nanoemulsions

Abstract

The aim of this work was to evaluate the effect of sodium alginate incorporation procedure on the physicochemical properties of nanoemulsions formed by microfluidization. Emulsions prepared consisted of corn oil and Tween 20 as dispersed phase and sodium alginate solution as continuous phase. In order to obtain nanoemulsion A (NA), both phases were microfluidized together. On the other hand, coarse emulsion without sodium alginate was microfluidized and mixed with a microfluidized (MA) or non-microfluidized (N-MA) sodium alginate solution leading to nanoemulsions B(MA) and B(N-MA), respectively. NA exhibited the smallest particle size (261 nm) and monomodal distributions with a polydispersity index of 0.25. The ζ-potential, viscosity and WI of NA were −37 mV, 22.7 mPa s and 57.28, respectively. Spectroscopic, chromatographic and electron microscopic techniques were used to evaluate changes in microfluidized alginate molecules when they were within emulsions. After microfluidization, alginates suffered depolymerization and further rearrangement, changing the disposition of polymer chains around oil droplets and nanoemulsions characteristics. Thus, these results evidence the significant impact of sodium alginate incorporation procedure on the physicochemical properties of nanoemulsions and how it can affect to the stability of the resulting systems which are going to be used as functional ingredients in food matrices.

This study was supported by the MINECO throughout project AGL2012-35635 and by the MINECO/FEDER throughout project AGL2015-65975-R. Authors María Artiga-Artigas and Alejandra Acevedo-Fani thank the University of Lleida for the pre-doctoral grant.