This equipment, which was invented at Cinvestav,
utilizes the electrical conductivity of native starch, modified
starch, cereals, tuber starch, and water. It can be used with
gelatinized starch or uncooked cereals, using either the whole
grain, milled grain, or flour. The best equipment for the thermal
tests consists of a nylamin basin with two Ni-Cu electrodes.
The sample is placed between the two electrodes and monitored
so as to measure its gelatinization properties (patent pending).
Other parts of the equipment include a function generator, a
signal amplifier, an AC-DC converter, a thermocouple with a
linear temperature range, and a computer interfaced for the
selected range. AC current of a constant frequency and either
constant or variable voltage is used. This electrical current
generates heat (the Joule effect) when it is passed through
the sample, which serves to both measure the properties of the
sample and cook it to the desired degree.