Influence of different maltodextrins on properties of O/W emulsions

Maltodextrins, low converted products of starch hydrolysis, are used in various emulsions to provide desirable viscosity, texture and mouthfeel. In order to assess behaviour of such emulsions in process of production (emulsification) as well as end products in application (pouring, spreading) it is necessary to investigate emulsification dynamics, globule size changes and rheological behaviour. In this work emulsification dynamics and the influence of different factors on dispersion and rheological characteristics of sunflower oil in water emulsions stabilized with food grade emulsifier with addition of maltodextrins were studied. Influence of oil and maltodextrin concentration and partial substitution of oil with equivalent quantity of maltodextrin were investigated, too. It was concluded that certain specific maltodextrin characteristics such as DE value (dextrose equivalent-measure of the degree of starch polymer hydrolysis) i.e. size of maltodextrin molecules significantly influence dispersion and viscous properties and stability of emulsions. With increase of oil concentration for the same concentration of maltodextrin in continuous phase emulsions undergo changes in flow type from shear-thinning to thixotropic and antithixotropic. Antithixotropy induced by shear, was result of formation of network due to two competing factors: orientation of deformed oil droplets and maltodextrin molecules and linking of oil droplets through maltodextrin molecules.