Abstract
Steam convection ovens utilize two types of heating method : convection heating and steam heating. To ascertain the heating efficiency of this type of oven, the heat transfer coefficient was measured with and without steam. In order to determine the cooking efficiency, the temperature increase and moisture loss of a sample potato (φ50 × 20 mm) were measured. The heat transfer coefficient was significantly higher with steam than without steam until the surface temperature of the heated food had reached 100°C. Above this surface temperature, the values with steam and without steam were nearly identical. The rate of increase in the surface temperature of the potato was in proportion to the increase in air temperature and the amount of steam, but the rate of increase in the temperature at the center of the potato did not follow this proportionality. This is believed to have been due to the fact that there was moisture loss from the potato surface at an early stage of heating when the air temperature was above 130°C with steam. On the other hand, when the air temperature was under 130°C with steam, there was no such moisture loss. These results indicate that the steam ratio and air temperature can be adjusted to control the cooking time and moisture content.
