A new method for determining the emulsion stability index by backscattering light detection

In the present study, the Δbackscattering (ΔBS) method was developed as a simple and sensitive tool for determining the emulsion stability index (ESI) by backscattering light detection. The backscattering light detection method uses emulsion-scanning technology to monitor physical behavior in an emulsion as a function of storage time. Emulsions were prepared by the homogenization (8,000rpm for 2min at 25C) of distilled water and perilla oil containing Tween 60, and the sample was quiescently incubated in a vial at 25C for 11h. To confirm this new methodology, the sum of ΔBS at the clarified layer, obtained from the backscattering flux profiles over the storage period, was compared with the ESI determined by the volumetric method. Our backscattering light detection method was compared with the volumetric method based on the emulsifier content. The sum of ΔBS at the clarified layer decreased as the ESI decreased, with a correlation of 0.999, 0.993, 0.998 and 0.998 for emulsions stabilized with 200, 300, 400 and 500μmol of emulsifier, respectively. Regardless of the emulsifier content in the emulsion, the R ² values for the fit curve, calculated by plotting the sum of ΔBS at the clarified layer against the ESI determined by the volumetric method, revealed strong linear relationship (R²=0.953). Our results suggest that the backscattering light detection method is a new tool for the quantitative determination of the ESI in an emulsion system.