Physical stability of model emulsions based on ethyl cellulose oleogels

Abstract

The purpose of this study was the evaluation of the physical stability of low-fat oil-in-water model emulsions containing oleogels based on ethyl cellulose), compared to emulsions with anhydrous milk fat. The oleogels were prepared using rapeseed oil with ethyl cellulose at the level of 4.5, 5.0, 5.5 or 6.0% w/w. The O/W emulsions (30/70 w/w) were stabilized by guar gum (0.6% w/w) and soy lecithin (5.0% w/w). The physical properties of oleogels and anhydrous milk fat (centrifugal stability, spreadability/penetration test), rheology and the physical stability of the emulsions (MS-DWS method, centrifugal/thermal stability) were determined, a storage test of the emulsions (CSA method, LUMiSizer) was also conducted. It was demonstrated that ethyl cellulose is an effective edible oil structuring agent. The increase in ethyl cellulose content enhanced the centrifugal stability and hardness of the oleogels. As a result of a microrheology analysis, it was found that the emulsion with anhydrous milk fat had the most elastic strength, macroscopic viscosity and the highest solids content. All emulsions demonstrated high centrifugal/ thermal stability. A higher temperature and extended storage time caused a reduction in the stability of all emulsions and increased the velocity of particle migrations. The ethyl cellulose-oleogels are potential fat phases for stable O/W emulsions, which could be used as a vegan alternative to traditional products based on animal components.