Interaction of gum arabic, maltodextrin and pullulan with lipids in emulsions.

The interaction of gum arabic, maltodextrin and pullulan with lipids in emulsion systems was investigated. Interfacial tension and interfacial viscosity measurements revealed that only gum arabic could adsorb and form a viscoelastic film at the oil-water interface. Good emulsifying activity was demonstrated for gum arabic, whereas fine emulsions could not be produced from the other polysaccharide solutions and oil. Frequency-dependent increases in the storage and loss moduli were observed for all the polysaccharide solutions. Such rheological behavior did not substantially change when maltodextrin and pullulan were mixed with oil to form emulsions. However, the frequency-dependence of the dynamic moduli disappeared in the gum arabic-stabilized emulsion, suggesting the formation of a network structure in which oil droplets could form junctions with gum arabic chains. The results on the inhibition of lipid oxidation by polysaccharides suggest that gum arabic protected lipids from the attack of lipoxygenase and free radicals by adsorbing at the oil droplet surface.