| dc.description.abstract | In this thesis, dielectric modeling of paddy and insect (R. dominica) was developed to
analyze the characteristics for microwave heat treatment to the Malaysian paddy
MR219. Electromagnetic fields at lower frequencies (< 1GHz) are of great significance
for heating the paddy, because 100% mortality of lesser grain borer, R. dominica (F.)
and weevil, S. oryzae may be obtained with minimal losses of rice quality when
subjected to the same electromagnetic field. The electromagnetic behavior of the
dielectric modeling of paddy and cavity with excitation waveguide was analyzed to
simulate the electric field distribution. The temperature dependency of the dielectric
properties of R. dominica (F.) and paddy MR219 were analyzed for the frequency range
of 200 MHz – 20 GHz and for the temperature range of 240 C – 650 C. The response
surface method was used to develop the relationship between the dielectric properties
and related factors (i.e., temperature, frequency and moisture) in terms of regional and
3D views. General equations that utilize frequency, temperature and moisture, were
developed to describe the dielectric properties. Microwave simulation was used to
model the lethal value of R. dominica and S. oryzae in terms of lethal temperature per
unit absorbed energy. The proposed dielectric modeling and microwave simulation
analysis of bulk paddy in the microwave cavity were validated with the actual
microwave heating, thereby confirming the accuracy of this approach in simulating the
novel heterogeneous post-harvest bulk paddy inside the microwave cavity. Mortality
and energy absorption were analyzed and modeled in terms of increasing temperature.
The world-wide interest in reduced pesticide use for secure health and microwave
heating is the possible effective means in heat treatments to control insects in post
harvest paddy or milled rice. The nutritional results of paddy MR219 showed that the
microwave-treated samples are significantly the same as the microwave untreated
sample. Sensory qualities and characteristics were not affected by the treatment. In the
modeling, standard errors were small and factors (i.e., frequency, temperature or
moisture) proved a meaningful addition to this model. | en_US |
