Potato chips reduced in diameter by about 10%, and expand
thickness by 3% at the end of frying. Fluctuations in diameter values
were more pronounced at the lowest temperature.
Porosity of potato chips increases during frying due decrease in
bulk density and increase in true density, which are caused by
water loss.
The microstructure of vacuum-fried potato chips is greatly affected
by frying time. Shrinkage of the cells and collapse of the
wall, as well as, disruption of starch granules occur as frying
progresses.
The maximum convective heat transfer coefficient of potato
chips during vacuum frying was between 2200 and 2650 W/m2 K
in the temperature range of 120–140 C. These values were obtained
during the first 20 s of frying where the moisture loss rate
was highest.