MODELING MOISTURE AND CHEMICAL CHANGES DURING BULK CURING OF FLUE–CURED TOBACCO

Mathematical models to predict moisture content, chlorophyll, starch, and reducing sugar concentrations were developed as a function of curing variables like temperature, initial moisture content, airflow rate, time, and initial chemical concentrations. The moisture removal model was based on a two–term (liquid and vapor) thin–layer drying equation, while chlorophyll, starch, and respiration models were based on first–order rate equations. Several product parameters required in secondary equations were determined through regression and comparison of root mean square errors. The models were fitted to the experimental data collected during the first year of the experiments (1997) to determine the product parameters by minimizing root mean square errors. The models were then verified using the experimental data obtained in the second year of the experiments. The models will help predict effects of curing variables on rate of moisture removal and chemical concentrations in the cured tobacco leaf. This information will contribute to the optimization of the curing process in terms of process efficiency and product quality.