|
Abstract
A series of measurements of dielectric properties
for food materials were made in the temperature range -20 to + 60°C using the cavity
perturbation technique described in the first paper of this series. Variables
studied besides temperature were preparation technique, pretreatment
and composition of the food materials. Results obtained were consistent,
reproducible and in fair agreement with literature data available. For moist
foods a very sharp rise in dielectric properties is seen during thawing,
followed by a gradual decrease with further temperature increase, except for
salted foods where a continued increase with temperature in loss factor was
found. A clear positive correlation between water content and  was found but not for  . Dielectric
properties decreased with increasing fat content, and loss factor increased
with salt content. In general, freezing, short time frozen storage, thawing
and rate of heating had little influence on the data determined, with the
exception of thickened gravy without stabilizer. Penetration depths are
presented as a function of , and , and the practical significance of the data obtained are
discussed.
|