Anomalous Diffusion Mechanism for Water in Native and Hydrophobically Modified Starch Using Fractional Calculus

Fractional calculus is a method to predict processes mathematically. This study uses fractional order models to determine whether starch hydration is governed by Fickian or anomalous diffusion. Native and modified starches are compared and classified based on their diffusive characteristics and the type of diffusion observed. The study aims to adjust the equation of the analytical solution of the diffusion model to study the hydration of both native and modified starches. The fractional order diffusion model is generalized to compare the two models and identify whether anomalous mechanisms exist in native and modified starches. The results show that water absorption by native and modified starch granules is characterized by anomalous diffusion. This is due to the temperature conditions and differences in the chemical potential of the starches. It is verified that the diffusive characteristics of native and modified starches differ under the same hydration conditions.