Stability and rheology of corn oil-in-water emulsions containing maltodextrin

The influence of maltodextrin concentration (0-35 wt%) and dextrose equivalent (DE = 10-36) on the stability and rheology of 5 wt% corn oil-in-water emulsions stabilized by Tween 80 was studied. Creaming stability, mean droplet diameter, xi-potential, and apparent shear viscosity of emulsions were measured. Rapid creaming was observed when the maltodextrin concentration exceeded a particular value, referred to as the critical flocculation concentration (CFC), which was attributed to depletion flocculation caused by the non-adsorbed maltodextrin. The CFC (wt%) decreased as the DE value of the maltodextrin decreased, i.e., as the molecular weight increased. Above the CFC, emulsions showed a small increase (<15%) in mean droplet diameter (d(43)) after one week storage, which was attributed to enhanced coalescence of the flocculated droplets. The apparent viscosity of emulsions increased steeply when the maltodextrin concentration exceeded the CFC, and the emulsions exhibited distinct shear thining behavior. The results were interpreted in terms of the impact of maltodextrin on the strength of the colloidal interactions between the emulsion droplets. Addition of maltodextrins to emulsions can be used to create emulsions with different physicochemical and stability properties. (C) 2004 Elsevier Ltd. All rights reserved.