Novel starch based emulsion gels and emulsion microgel particles: Design, structure and rheology

Abstract

Novel starch-based emulsion microgel particles were designed using a facile top-down shear-induced approach. The emulsion droplets were stabilized using octenyl succinic anhydride (OSA) modified starch and incorporated into heat-treated and sheared native starch gels, forming emulsion gels. Using gelation kinetics and small deformation rheological measurements of sheared native starch gels and emulsion gels, OSA starch-stabilized emulsion droplets were demonstrated to act as "active fillers". By varying native starch concentrations (15-20wt%) and oil fractions (5-20wt%), optimal concentrations for the formation of emulsion microgel particles were identified. Microscopy at various length scales (transmission confocal laser scanning and cryo-scanning electron microscopy) and static light scattering measurements revealed emulsion microgel particles of 5-50μm diameter. These novel emulsion microgel particles created via careful combination of gelatinized native starch and OSA stabilised-emulsion droplets acting as active fillers may find applications in food and personal care industries for delivery of lipophillic molecules.

Keywords: Active filler; Emulsion microgel particle; Encapsulation; Native starch; OSA starch; Rheology.