Modeling the drying kinetics of alginate particles considering shrinkage

Abstract

AbstractAlginate is an anionic and biodegradable biopolymer of natural occurrence, typically obtained from brown algae, being studied, and used in several applications in biomedicine and food industry by its low toxicity, low cost, and its gelification obtained by the addition of bivalent cations (Ca2+), besides being able to storage large amounts of liquid in its structure. In this context, this work aims to study the drying and shrinkage kinetics of this biomaterial. Microparticles of alginate were synthesized by the ionic gelification method using calcium chloride as reticulant agent. These microparticles were submitted to drying experiments conducted at 40, 50, and 60°C. A mathematical model which considers the microparticles moisture and volume change with time was proposed to model the drying process. Considering that the radius depends on time as Page and Sigmoid equations, two mathematical models were obtained. Both models were able to describe the experimental data and the kinetic parameters were adjusted as an exponential function of temperature (R2 = 0.99). The statistical analysis of the residues between calculated and experimental data indicates an adequate prediction, with Page's model fitting more accurately to the data sets. Akaike's test also indicated the coupled Page model as the most adequate.Practical ApplicationsThe results presented in this paper provide mathematical methods of modelling the hydration kinetics of alginate particles and fitting the parameters which can help understanding the mass transfer and shrinkage phenomena during drying. Those characteristics are essential in describing alginate particles due to the high amount of water that they contain. Describing the drying kinetics of such particles may help to project and optimize equipment involved in alginate particles production process.