Abstract
An electromagnetic cooking device has come into wide use in houses recently. However, a strange phenomenon that the flavor of steamed food come amiss compared with a usual gas heating has been observed. This phenomenon might be caused by the water quality change during cooking. Therefore, tap water was heated by electromagnetic heating or gas heating, and then the water quality change was analyzed. In electromagnetic heating, water quality changed significantly, that is, pH rose from 7.2 to 8.3, and hardness increased from 19.0 to 33.2 mg/L for the first 10 minutes cooking. On the other hand, in the case of gas heating, it had the minor transition. When distilled water was heated by both methods, transition of water quality was scarcely observed. It is suggested that the components of tap water (Ca, Mg, Na, K) attached to surface of pan as the water scale was eluted into the water by strong electromagnetic heating.
