Effect of formulation of alginate beads on their mechanical behavior and stiffness

Abstract

Effect of formulation of alginate beads on their mechanical behavior and stiffness. AbstractThe aim of this work was to determine the effect of formulation of alginate beads on their mechanical behavior and stiffness when compressed at high speed. The alginate beads were formulated using different types and concentrations of alginate and gelling cations and were produced using an extrusion-dripping method. Single wet beads were compressed at a speed of 40 mm/min, and their elastic limits were investigated, and the corresponding force versus displacement data were obtained. The Young's moduli of the beads were determined from the force versus displacement data using the Hertz's contact mechanics theory. The alginate beads were found to exhibit plastic behavior when they were compressed beyond 50% with the exception of copper-alginate beads for which yield occured at lower deformation. Alginate beads made of higher guluronic acid contents and gelling cations of higher chemical affinity were found to have greater stiffness. Increasing the concentration of alginate and gelling ions also generated a similar effect. At such a compression speed, the values of Young's modulus of the beads were found to be in the range between 250 and 900 kPa depending on the bead formulation.

Modified PVA-alginate encapsulated photocatalyst ferro photo gels for Cr(VI) reduction

“…In general, the stiffness of alginate magnetic beads may be considered to depend on the degree of cross-linking. Higher alginate concentration produces stiffer beads due to the increase in cross-linking density [14]. Fig.…”

“…The compression tests of the beads were performed using a Texture Analyser TA-XT2i (Hounsfield Corp, UK) attached with a 25 N force transducer. Spherical beads were used in the study and each bead is immersed in water and placed onto a platform as reported by Chan et al [14]. The bead was compressed by a flat end probe up to a deformation (ratio of displacement to initial bead diameter) equivalent to 30% from initial size at a test speed of 40 mm/min at room temperature of 25 ± 1 • C. In order to ensure reproducible results; the number of beads compressed per sample was kept to 3.…”

The influence of different polymers on viability of Bifidobacterium lactis 300b during encapsulation, freeze-drying and storage

“…The value for the surface tension of the alginate based solutions at 15 g/L was obtained from Chan et al (2011a) and considered constant for all seven samples.…”

“…Chan et al (2011a) have shown that low viscosity of the filler leads to high shrinkage factor. In accordance to what was previously found, this trend is also observed in the present work as can be seen in Fig.…”

“…Chan et al (2011a) related the survival of the encapsulated probiotic cell to the structural integrity of the granules. Alginate based granules are frequently used for the entrapment of probiotics (Anal and Singh 2007;Brinques and Ayub 2011;Burgain et al 2011), due to its biodegradability and biocompatibility, resistance in acidic conditions, successful release in intestinal media (Sultana et al 2000) its thermo tolerance and freeze-drying resistance (Cheow and Hadinoto 2013).…”