Measurement of oil droplet size distributions in food oil/water emulsions by time domain pulsed field gradient NMR

A new method for measuring oil droplet size distributions by means of a benchtop pulsed field gradient NMR spectrometer operating in the time domain is presented. The continuous water phase is successfully suppressed by gradient pulses in order to measure the dispersed oil phase. Simulations show that for most common oil/water food emulsions the influence of droplet diffusion is negligible due to a rather large droplet size or a high viscosity of the continuous water phase. The merits of the NMR method relative to other methods are discussed in terms of sample preparation, sensitivity to cluster phenomena, and matrix effects. Preliminary results of a short validation study show a good correlation with conventional reference techniques. (C) 2001 Academic Press.