Drying kinetics of passion fruit peel for tea products

Chiang Mai University, Department of Mechanical Engineering, 50200 Chiang Mai, Thailand

^* Corresponding author: woontrw@gmail.com
^† Corresponding author: siva@dome.eng.cmu.ac.th

Abstract

An important step in the development of passion fruit tea products is the drying procedure. This procedure uses a lot of energy. The optimization of drying needs knowledge of the drying kinetics. This paper focuses the development of drying kinetics for passion fruit peel. The experiments were conducted utilizing a thin layer dryer with drying air temperatures in the range of 45°C to 65°C The drying air velocity was constant at 1 m/s. The passion fruit peel were dried from their initial moisture content of 559±16% db to a final moisture content of 50±1% db. The models for the kinetic drying proposed by the authors are the Newton model, Page model and the Logarithmic model. The parameters for the drying kinetic models were found by curve fitting the experimental data using non-linear regression. The criteria for evaluating the models were the coefficient of determination (R²), a root mean square error (RMSE) and a reduced chi- square (x²). It was found that the drying kinetic model for passion fruit peel which gave the best fit was the Page model. This drying kinetic model can be applied to find optimum drying conditions.