Emulsion preparation with modified oat bran: Optimization of the emulsification process for microencapsulation purposes

The objective of this study was to develop an oil in water (o/w) emulsion using modified oat bran (MOB). Test emulsions containing 5% rapeseed oil were prepared by varying the content of MOB and maintaining the solid content constant (20%) by using corn syrup solids (DE34) as filler. A central composite (CC) design was applied as a tool to obtain a stable and low viscosity emulsion. The effect of concentration of MOB, homogenization pressure and homogenization time on the emulsion stability (at 25 °C for 26 h), viscosity and particle size were determined. The concentration of MOB in the recipe significantly influenced the emulsion properties whereas the homogenization pressure and the homogenization time had no statistically significant influence on the emulsion properties. Further experiments, however, showed that increasing the homogenization pressure decreased the emulsion viscosity. Emulsions prepared using a MOB concentration of 1.55% and homogenized at 60 MPa for 10 min, exhibited excellent stability, low viscosity, small enough mean particle size and narrow particle size distribution. Modified oat bran containing deamidated oat protein possesses an excellent capability to form stable emulsions which might be suitable for microencapsulation.