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 between two electrically isolated metallic plates, acting as electrodes. Water content measurements are calibrated against the conventional loss-in-weight method. Once calibrated the conductance technique yields satisfactory accuracy, 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 demonstrated by moisture absorption/desorption experiments. The method is easy to use and calibrate, readily installed and can be implemented at relatively low cost. The conductometric technique employed in this work, enabled rapid and reliable water content measurements of maize starch sheets (thickness of 0.085, 0.5 and 1 mm) ranging from around 0% to 20%. (C) 2000 Elsevier Science Ltd. All rights reserved.