Water content measurement of thin sheet starch products using a conductance technique

An electrical conductance technique for water content measurements of drum- drying and extrusion cooking starch products is described in this paper. It is based on the conductance measurement of a thin sheet of material betwee n two electrically isolated metallic plates, acting as electrodes. Water co ntent measurements are calibrated against the conventional loss-in-weight m ethod. Once calibrated the conductance technique yields satisfactory accura cy, repeatability and stability compared to the loss-in-weight method. Yet, it offers the distinct advantage of a major reduction in measurement time (less than a minute). The latter is of critical importance, as clearly demo nstrated by moisture absorption/desorption experiments. The method is easy to use and calibrate, readily installed and can be implemented at relativel y low cost. The conductometric technique employed in this work, enabled rap id and reliable water content measurements of maize starch sheets (thicknes s of 0.085, 0.5 and 1 mm) ranging from around 0% to 20%. (C) 2000 Elsevier Science Ltd. All rights reserved.