PREDICTING DRYING BEHAVIOR OF SPAGHETTI IN A CONTINUOUS INDUSTRIAL DRYER WITH THE MODELS DETERMINED IN A LAB SCALE BATCH SYSTEM

In the first stage of this study experimental data were obtained by us ing a lab scale batch type dryer, operating under various constant tem perature/constant relative humidity combinations; then a mathematical model was determined for the effective diffusivity of moisture in spag hetti. In the second stage of the study the model obtained in the lab scale batch type dryer was used to calculate the moisture content of t he spaghetti leaving continuous industrial scale dryer, and its succes s was tested by comparing with the experimentally determined moisture content of the product. The model was not found successful and correct ed. Mathematical models based on experimental data obtained in a bench -top laboratory dryer underestimated the apparent equilibrium moisture content and over estimated the effective diffusivity of water in spag hetti in industrial scale continuous drying equipment. The structural differences in the product, extrapolation of the data beyond the range of the original experiments, variations in mode (batch versus continu ous), surface-to-volume ratios, flow patterns, and geometry associated with each drying system were anticipated as the cause of the scale up problem.