Prediction models for shape and size of ca-alginate macrobeads produced through extrusion–dripping method

Abstract

The aim of this work was to develop prediction models for shape and size of ca-alginate macrobeads produced through extrusion-dripping method. The relationship between the process variables on the shape and size of the alginate drops before and after gelation was established with the aid of image analysis. The results show that a critical Ohnersorge number (Oh)>0.24 was required to form spherical beads. The shape transition of ca-alginate beads could be typically distinguished into three phases along the collecting distance and it was affected by the combined influence of the solution properties, the collecting distance and the drop size. Mathematical equations and a master shape diagram were developed to reveal a clear operating region and the overall process limits within which spherical ca-alginate beads could be formed. In terms of bead size, the overall size correction factor (K) which accounted for the liquid loss factor (k(LF)) and the shrinkage factor (k(SF)), varied between 0.73 and 0.85 under the experimental conditions. The size prediction model correlated well with the experimental data. The approach and the outcome could be used as a model to develop prediction tools for similar bead production systems.

Alginate liquid core capsule formation using the simple extrusion dripping method

“…This is because the concentration of calcium chloride below 10 g/l was insufficient to form strong gel membrane. When the concentration of calcium chloride below the critical value [18], the capsule membrane was weakly gelled and caused the formation of less spherical capsules [1]. Conversely, the CMC concentration has no apparent effect on SF of the capsules, as indicated by the results of the solution formulations of LC5-LC7.…”

“…Encapsulation technology has been widely used in cells cultivation system, medicinal drug and nutritional supplements delivery, as well as liquid-liquid extraction [1][2][3][4][5][6][7][8][9]. In general, active ingredients such as living cells, drugs, extracts, nutrients and solvents are encapsulated (or confined) in a gel particle, either in the form of capsule or bead [1][2][3][4][5][6][7][8][9].…”

“…In general, active ingredients such as living cells, drugs, extracts, nutrients and solvents are encapsulated (or confined) in a gel particle, either in the form of capsule or bead [1][2][3][4][5][6][7][8][9]. Liquid core capsule is a gel particle made up of an internal liquid core that contains the active ingredient and an external shell "membrane" layer surrounding the active ingredient [4][5][6][7][8].…”

“…In the formation of liquid core capsules, the active ingredient is mixed with calcium chloride solution and then extruded as droplets into alginate solution. The calcium cations interact with alginate molecules to form gel following the well-known egg-box model [1]. The formation process of Ca-alginate liquid core capsules is basically inversed of that of the typical Ca-alginate beads.…”

Optimization of Conditions for Obtaining Alginate/Olive Oil Capsules for Application in Dairy Industry

“…Two types of capsules are prepared depending on the encapsulation system chosen -reservoir type capsules, wherein the active agent is separated from the capsule by a membrane; and matrix type capsules, in which the content is distributed 1 Corresponding author. Mailing address: george_kostov2@abv.bg uniformly in the nucleus, which allows obtaining very small particles (Rathore et al, 2013;Zuidam and Shimoni, 2010;Chan et al, 2009;Chan, 2011). Oil encapsulation is necessary due to a many reasons like the conversion of the oil phase to solid state for easier transportation, handling or incorporation into a food matrix.…”