Colloid Characteristics and Emulsifying Properties of OSA Starches

The objective of this paper was to characterize commercially available octenyl-succinate starches (OSA starches), Purity Gum 2000 and Hi-cap 100, by determining their viscous behaviour and characteristics and molecular mass, as well as to examine their emulsifying properties in corn oil-in-water emulsion system. Huggins equation and extrapolation procedure were employed to determine intrinsic viscosity and Huggins constant of OSA starches in water, KOH and various electrolyte solutions, as well as in dimethylsulfoxide (DMSO). The viscosity-average molecular mass was calculated. Emulsifying properties were evaluated analysing the rheological behaviour, particle size distribution and creaming stability of the emulsions as a function of emulsification time, dispersed phase content, emulsifier concentration and combination with micro molecular emulsifier polyoxyethylene (20) sorbitan monooleate (Tween 80). Intrinsic viscosities as well as molecular mass of Purity Gum 2000 were higher than ones determined for Hi-cap 100. Emulsions prepared with Purity Gum 2000, compared to those containing Hi-cap 100, had better stability and higher viscosity, which increased with the increase in dispersed phase and emulsifier concentration. The stability of the emulsions prepared combining OSA starches with surfactant Tween 80 was largely dependent of the emulsification time, while the emulsions stabilized only with OSA starches were not significantly influenced by this factor.