Electro-hydrodynamic spraying of soybean oil

Electro-hydrodynamic spraying can be used to produce even coverage of oil onto foods and food surfaces, however soybean oil does not charge well and lecithin is one of the few additives that can be used to decrease resistivity in a food system. Changing lecithin content and temperature affects the resistivity, viscosity and surface tension. These parameters, along with voltage and the calculated weber number, affect the spray quality. Soybean oil was sprayed on oil sensitive paper with 0 to 15% lecithin, at 4 to 47°C, 0 to 40kV, to determine droplet distribution. The number of droplets increased with decreasing resistivity, decreasing viscosity, increasing weber number, intermediate lecithin concentration, increasing temperature, increasing voltage, and had a very weak correlation to surface tension. Voltage had the greatest effect on the number of droplets followed by lecithin content and temperature. Thus, 40 kV, 47°C and 10% lecithin produced the smallest droplets.