Abstract

In this study, mathematical modeling of microwave (MW) assisting hot air drying of thin-layer papaya (Carica papaya L.) slices with 5 ± 1 mm thickness in an experimental drying process is presented. The osmosis solution comprised 50% sucrose + 2% NaCl solutions. The osmosis dehydration characteristics obtained by solid gain (SG), water loss (WL) and weight reduce (WR) parameters. The drying air velocity (0.9 ± 0.1 m/s) and temperatures (40, 50 and 60°C) were examined in drying papaya slices from initial moisture content of 700 ± 2% (d.b) to moisture content of 20 ± 1% (d.b). The slices were subjected to 10 s 540 W MW power at each 15 min interval as an auxiliary drying method. Ten thin-layer drying models were fitted to drying experimental data of papayas, implementing non-linear regression analysis techniques. The statistical analysis using correlation coefficient (R²), chi-square (χ²) and root mean square error (RMSE) concluded that, the best model in terms of fitting performance for MW assisted hot air drying of papaya pretreated in osmosis solution at 40 and 50°Ð¡ was page model while that at 60°Ð¡ was two-term model.

Key words: Papaya, mathematical modeling, microwave (MW), cabinet drier.