Effect of glycerol on the morphology of starch-sunflower oil composites

The presented study involves the encapsulation of sunflower oil in starch b y casting emulsions of oil in aqueous starch solutions. Glycerol was used a s a plasticizer and lecithin was used as an emulsifier, to improve the emul sion stability. Increasing glycerol concentration in the samples resulted i n different dispersed phase morphologies in the starch-sunflower oil compos ites. It was observed that increasing glycerol concentration resulted in a decrease in the particle sizes and polydispersity of the oil droplets. The two determining parameters on the formation of the dispersed phase during e mulsification; viscosity and interfacial tension between two phases, were i nvestigated to evaluate the effect of glycerol on the system. Since glycero l was found not to affect the viscosity of the aqueous starch phase, it was concluded that glycerol affects the dispersed phase morphology due to its effect on interfacial tension between the oil and aqueous starch phase, dur ing emulsification. (C) 1999 Elsevier Science Ltd. All rights reserved.