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Use of Ohmic Equipment to Determine the Thermal Properties of Starch and Other Organic Materials
Description of the Equipment:
This ohmic equipment has been used to test the temperature and degree of starch gelatinization in cereals and other grains, but could also be used with other organic and inorganic materials that conduct electricity.
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.
