Abstract
The effects of radiant characteristics of heaters on food processing were studied experimentally. Four heaters were employed : 1) a halogen heater, 2) a seathed heater, 3) a far-infrared rays heater, and 4) a broad-band rays heater. The radiative heat transfer rate in the oven was measured by an aluminum block, and then the heating and evaporation process of water was measured. The baking process of sponge cakes was also studied.
The experiments showed that an important parameter of the heaters is the wavelength at the emission peak. A decrease of this wavelength results in an increase of the radiative heat transfer rate in the oven. The rate of increase of temperature and the evaporation rate of water depend on the radiative heat transfer rate. For baking the sponge cake, a shorter baking time is attained by the heater which has the higher radiative heat transfer rate. The heater which radiates longer wave rays and has the higher radiative heat transfer rate results in a darker surface of the sponge cake.
