טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentAsher Shazman
SubjectExamining for Possible Non-Thermal Effects in the Microwave
Oven
DepartmentDepartment of Biotechnology and Food Engineering
Supervisors Professor Emeritus Mizrahi Shimon
Professor Emeritus Cogan Uri


Abstract

The absorption of microwave radiation energy (0.1~3 GHz) produces heat and may cause a thermal damage to different tissues in the human body. Therefore, in most countries the public is protected by standards that limit the intensity of the microwave radiation absorbents by the human body. However, the assumption that thermal effect (heating) is the sole harmful factor has been debated by many reports, claiming that athermal (non-thermal) effects exist as well. Such effects were claimed to change the chemical or the physical behavior of different systems while the temperature and all other parameters remain constant.  In the current study a number of chemical, biological and physical systems were tested for athermal effects in a very well controlled, high intensity, continuous flow microwave system (2.45 GHz, energy absorbance up to 1000 W/Kg in a continuous radiation up to 48 hours). The intensity of the microwave was 100~2000 times greater than the common standards of exposure. As a control, a conventional heating system was used, not only to maintain the same temperature but also the same rate of heating. By carefully eliminating any source of artifacts, all data failed to show any significant athermal effect in the formation of Maillard reaction products, in proteins denaturation, in polymer solubility, in mutagenesis of bacteria, in mutarotation equilibrium of α/β-D-glucose at water/ethyl alcohol solution, and in the solubility of NaCl. The results of this study are in contrast to what was previously reported for some of the tested systems.