Se ha realizado un estudio de la distribución del tamaño de gotas y de las propiedades viscoelásticas lineales de emulsiones concentradas de aceite en agua, estabilizadas con diferentes proteínas (cangrejo, gluten y soja). Los sistemas estudiados siempre presentan un comportamiento típico de emulsiones altamente concentradas con un alto grado de floculación. Se ha observado que un incremento de la velocidad de agitación empleada durante la preparación o de la concentración de emulsionante dan lugar a un aumento de los módulos viscoelásticos (G' y G") y a una disminución del tamaño de gotas. Por tanto se produce un reforzamiento del entramado formado por asociación de las gotas de fase dispersa y como consecuencia, un aumento en la estabilidad de las emulsiones. | Droplet Size Distribution (DSD) and linear viscoelastic properties of concentrated o/w emulsions stabilized by different proteins (crayfish, gluten and soybean) have been studied. A typical behaviour of highly concentrated emulsions with a high degree of flocculation has been found. An increase in energy input for the emulsification process or in emulsifier concentration leads to an increase in both viscoelastic moduli (G', G") as well as to a decrease in droplet size. Thus, an enhancement of the entanglement network produced by association of protein molecules that are surrounding oil droplets or are present in the continuous phase takes place, leading to a significant improvement of emulsion stability.

In order to utilize rice flour in food systems with high water content, rice flour was dispersed into water to prepare a rice flour suspension and emulsion. Stability of the suspension was significantly increased by heating processes in combination with homogenization processes. The improved stability was probably due to finely dispersed rice flour particles (-10microm) and gelatinized starch granules. Since oil droplets with a size of several micrometers disperse in an aqueous phase of many real food emulsions, rice flour is expected to be utilized as a fat replacer mimicking oil droplets. Emulsions were prepared dispersing soybean oil into a rice flour suspension. The emulsion was relatively stable to oil droplet coalescence for 7 days. Starch and proteins such as 10-16 kDa prolamin adsorbed to oil droplet surfaces to stabilize the emulsion. These results suggest that rice flour is expected to be utilized as a natural emulsifier in the food industry.