It is observed that at all moisture contents, thermal conductivity
of guava fruit increases with increase in time. But at lower
moisture levels Thermal conductivity is relatively low with higher
moisture levels with increase in temperature or time. Because, as
the moisture evaporates the sample shrinks and the rate of shrinkage
in the initial stage of heating is more, leading to porosity i.e.
entrapped air which is a bad conductor of heat, hence decrease
in the thermal conductivity [17,18