Simulation of Leaching of Starch from Potato in a Batch Extractor

In this paper, extraction of starch and protein from potato during leaching in a batch extractor, using distilled water as the solvent, was investigated. The experiments were carried out by soaking bulk of infinite slab shape potato samples in distilled water in a temperature and agitation controlled batch extractor at the three temperatures of 30, 45 and 55?C. A mathematical model was developed for prediction of mass transfer during the leaching process, by defining a partition factor (K) as the ratio of the concentration on the surface of the body to that in the bulk of solution. Diffusion coefficients of the solutes and moisture were obtained by fitting the experimental data of solute loss and moisture gain to the first six terms of the series solution of the mathematical model by using a non-linear regression analysis. The diffusivity values for starch, protein and moisture were evaluated between 0.273u10-10 and 1.577u10-10 m2/s, with adjustment parameter R2 values in the range of 0.941 to 0.986 and mean relative error (MRE) values between 0.092 and 0.356, respectively. Results showed that the proposed model could be used for explaining the diffusion of solutes and moisture into the potatoes, during the leaching process, with acceptable degree of goodness.