Mutual and adverse interplay of pretreatments on drying characteristics of taro slices.

Background: The utilization of taro has been restricted by its perishability, and drying is one of the methods commonly used in its preservation. There is however the need to understand the drying process in order to have an efficient operation. This study focused on the thin‐layer drying kinetics of taro slices to provide information toward optimization of the process. Fresh taro corms were washed, sliced, and pretreated by steam (B), dipped in sodium meta‐bisulfite solution (S), and a combination of both pretreatments (SB) while a portion was left untreated (C). Drying was done in a laboratory oven at 2 m/s air velocity and varying temperatures (50, 60, and 70°C). The drying responses were determined and subjected to both multiple and nonlinear regression analyses using standard procedures. Results: Results showed that taro slices were dried from initial moisture content between 369 and 406 kg H20/kg d.m to final moisture content between 5.29% and 12.4% db. The drying took place predominately in the falling rate period with higher drying rates recorded for pretreated samples. The third‐order polynomial equation modeled the drying responses effectively. Based on responses such as the average, maximum, and minimum drying rates, the drying process of taro slices had its sweet point at 2.03 min, 1.61% w/w, and 59.27°C of blanching time, sulfiting concentration, and drying temperatures, respectively. Midilli and logarithmic models were the best fit for predicting the drying behavior of treated and untreated samples, respectively. Conclusion: The study was a step in providing information for thin‐layer drying of taro, which could form a basis for the development of drying system and methods for taro and other similar produce. [ABSTRACT FROM AUTHOR]