Agriculturae Conspectus Scientificus, Vol 72, No 4 (2007)

The Thin-Layer Modelling of Tomato Drying Process


Pages: 343-349


In this study thin-layer drying characteristics of tomato were investigated using a hot air convective dryer at a constant airflow velocity of 0.8 m s-1 and air temperature in the range of 50-70°C. The experimental drying data were fitted to the four well-known drying models i.e. the Page, Henderson and Pabis, logarithmic and two term models. Th e statistical validity of fit was measured using the coefficient of determination, mean relative percent deviation, root mean square error and reduced chi-square. Of all four models, the logarithmic model proved to be the best for predicting drying behaviour of tomato with values of coefficient of determination R2 greater than 0.99. The effective diffusivity was determined to be in the range of 2.56-4.28x10-9 m2 s-1 for nontreated samples and 4.29-6.28x10-9 m2 s-1 for blanched ones in the temperature range of 50-70°C. The temperature dependence of the effective diffusivity was described by the Arrhenius-type relationship. The activation energy values for non-treated and blanched samples were 23.73 and 17.55 kJ mol-1, respectively. Also, air temperature and pre-treatment affected the quality parameters of dried tomato.


drying; tomato; moisture content; effective diffusivity; activation energy; colour

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