The dielectric components of egg components, albumen (egg white)
and yolk were investigated by Dev, Raghavan, and Gariepy (2008). The
dielectric properties were measured at various temperature (0–62 °C)
and frequency (200 MHz to 10 GHz). It was observed that the albumen
had higher dielectric properties than yolk which indicate that albumen
possessed a higher heating rate than yolk. Surprisingly, it was found
248 S. Chandrasekaran et al. / Food Research International 52 (2013) 243–261
that the egg-shell and shell membrane were transparent to microwave
due to low moisture content and the lesser extent of composition
and structure of shell proteins. Consequently, for in-shell eggs,
the heating rate of albumen was similar to that of yolk (Dev et al.,
2008). Kumar and Sanavullah (2011) identified the locations within
a microwave oven cavity to cook an egg without explosion using theoretical
analysis. Eggs or packaged products are advised not to be
kept in a microwave oven due to the generation of high internal
pressure in the sealed objects. In an egg, the dielectric properties of
albumen are higher than the yolk. Using a mathematical model, the
high energy points and the low energy points were identified in
the microwave oven. At high energy points, albumin got cooked
fast and started to splatter whereas at low energy points the albumin
was slowly cooked without explosion. A domestic microwave oven
operating at a frequency of 2.45 GHz with adjustable power from 0
to 750 W and a rectangular wave guide of TE10 mode positioned at
the right side of the microwave cavity was used for heating egg samples.
For a microwave cavity of 29 cm × 29 cm × 19 cm, the low energy
points are identified as 5 b x b 10, 6 b y b 9 and 2.5 b x b 5,
5 b y b 10 respectively. Here, the origin is at the front left corner
and the y values are measured from front to back. It was
recommended to keep the eggs at a low energy point and at low
power (40%) in order to avoid explosion in the microwave oven