The surface composition of model food products, consisting of varying amounts of sodium caseinate, maltodextrin and soya oil, was investigated after spray drying using Electron Spectroscopy for Chemical Ananlysis ESCA.

The results show significant enrichment of oil at the surface of the particles, possibly due to rupturing of emulsion droplets as the surrounding matrix hardens.

An significant enrichment of sodium caseinate relative to maltodextrin was also found.

The degree of enrichment of both components increased with decreasing bulk concentrations.

(Jones, J. R. et al., Journal of Food Engineering 118 (2013) 19-30)