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

Mathematical models to predict moisture content, chlorophyll, starch, and reducing sugar concentrations weredeveloped as a function of curing variables like temperature, initial moisture content, airflow rate, time, and initial chemicalconcentrations. The moisture removal model was based on a twoterm (liquid and vapor) thinlayer drying equation, whilechlorophyll, starch, and respiration models were based on firstorder rate equations. Several product parameters requiredin secondary equations were determined through regression and comparison of root mean square errors. The models werefitted to the experimental data collected during the first year of the experiments (1997) to determine the product parametersby minimizing root mean square errors. The models were then verified using the experimental data obtained in the secondyear of the experiments. The models will help predict effects of curing variables on rate of moisture removal and chemicalconcentrations in the cured tobacco leaf. This information will contribute to the optimization of the curing process in termsof process efficiency and product quality.