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Changes in water quality during heating in electromagnetic and gas heated pans and the relationship between water quality changes and temperature increase rate
Author(s) -
Sasaki Ken,
Hiratsuka Hiroshi,
Takeno Kenji
Publication year - 2006
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2005.01089.x
Subject(s) - tap water , water quality , water heater , natural gas , bicarbonate , liquefied petroleum gas , environmental science , environmental chemistry , chemistry , environmental engineering , geology , ecology , organic chemistry , geomorphology , inlet , biology
Summary Relatively large changes in the indicators of water quality, such as pH, hardness, and bicarbonate content, were observed during electromagnetic heating of pans of different tap waters and compared with pans heated by liquid natural gas (LNG) or liquid petroleum gas (LPG). For example, the pH and hardness of Hiroshima tap water were increased from 7.35 to 9.27 and from 19.0 to 35.7 mg L −1 , respectively, during 20 min of electromagnetic heating. When tap water from Tokyo was subjected to electromagnetic heating, the water hardness of 74.2 mg L −1 was increased by 52% after 20 min of heating. Such water quality changes were observed consistently in several tap water samples across Japan. These changes showed a close correlation with rates of temperature increase. It was suggested that mineral components (Ca and Mg), which were attached on the stainless steel surface of the pans might be released into the tap water with high calorific heating.