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 ben chtop pulsed field gradient NMR spectrometer operating in the time domain i s presented. The continuous water phase is successfully suppressed by gradi ent pulses in order to measure the dispersed oil phase. Simulations show th at for most common oil/water food emulsions the influence of droplet diffus ion 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 clust er phenomena, and matrix effects. Preliminary results of a short validation study show a good correlation with conventional reference techniques. (C) 2001 Academic Press.