Kinetics of Calcium Oxalate Reduction in Taro {Colocasia esculenta) Corm Chips during Treatments Using Baking Soda Solution

摘要

The oxalates content has caused limited utilizations of taro (Colocasia esculenta) as a food material. The insoluble oxalates, especially needle like calcium oxalate crystal may cause irritation, and swelling of mouth and throat. Removal of oxalates in food can be done by physical processes, such as soaking, boiling, and cooking or chemical process by converting them into soluble phases. The purpose of this research were to investigate the effects of baking soda concentration (0-10 % w/w) and temperatures (70-97 °C) on the reduction of calcium oxalate content in the taro corm chips and to develop a kinetic model of that process during boiling in baking soda solution. The kinetic model development was done by considering the dissolution of calcium oxalate, chemical reaction and thermal degradation that take place during boiling. The experimental results showed that increasing of baking soda concentration and temperatures were found to increase the reduction of calcium oxalate in the taro corm chips. Based on the product's functional properties, the best condition for calcium oxalate reduction was soaking in 10% w/w baking soda solution for 2 hours followed by boiling at 90 °C for 60 minutes. The kinetic modeling concluded that the calcium oxalate reduction was found to follow a pseudo first order reaction. The modeling results showed that the model is able to represent the phenomena quite well with the apparent reduction rate constant, k= 15.77 Exp (21.239)/RT minute~(-1).