Three-dimensional phase diagram for the centrifugal calcium-alginate microcapsules production technology

Encapsulation techniques are used increasingly in industries such as food, cosmetic, pharmaceutical or biomedical. The most commonly used polymer for encapsulation at this day is alginate. Depending on the application, different requirements need to be satisfied by the polymer capsules. In biomedical applications, controlled shape and size of the microcapsules are desired, together with a high production frequency and the possibility to process highly concentrated biopolymer solutions. Centrifugal encapsulation has been proved to be a promising technique, capable of meeting these requirements. The centrifugal production system depends on multiple operating parameters which influence the properties of the obtained capsules. So far, insufficient data and tools are available for the system behaviour prediction and for guiding the selection of the operating parameters. Here we present an extensive parametric study on the four relevant operating parameters of the centrifugal encapsulation technology (alginate viscosity, collecting distance, needle diameter, rotating speed), leading to the derivation of comprehensive phase diagrams of capsule shapes and sizes. These tools are expected to facilitate the generalisation of the centrifugal encapsulation, by allowing for the prediction of the process behaviour, the selection of operating parameters for a desired application, and the adaptation of the technology to any available equipment. Copyright © Elsevier Inc. All rights reserved. [Display omitted] •An extensive parametric study of the centrifugal encapsulation technology is carried out.•Novel dimensionless phase diagrams are constructed for the prediction of the centrifugal capsules production.•A procedure for parameter selection is proposed.•An automated image analysis procedure is defined for capsule shape classification.