Preparation and Characterization of Alginate Beads by Drop Weight

Abstract

The preparation and characterization of macro alginate beads are always associated with appropriate techniques involving precise measurement of shape, size, volume and density of the products. Depending on the type of application, encapsulation of macro alginate beads can be accomplished by various techniques including chemical, ionotropic, physical and mechanical methods. This work describes a method for preparing macro alginate beads through drop weight. The macro beads (2.85-3.85 mm) were prepared via different concentrations of alginate (0.5, 1.0, 1.5 and 2.0 g/L), dripping tip size (0.04-0.14 cm) and immersion into a predetermined concentration of calcium chloride (CaCl 2 ) bath. A custom made dripping vessel fabricated from acrylic plastic, connected to an adjustable dripping clamp was used to simulate the dripping process of the molten alginate at different tip sizes. It was observed that at different dripping tips, the correction factor for the alginate slurry was found in the range of 0.73-0.83. Meanwhile, the lost factor, K LF was observed at 0.93-2.3 and the shrinkage factors were limited to 2.00% from the overall distributed data. It was concluded that liquid properties had no effect on the liquid lost factor. The bead size prediction for different concentrations of alginate solution was compared to the experimental data. Subsequently, it was concluded that increasing the tip size caused the bead size to deviate almost 20% when compared to the experimental and predicted values, respectively.

Gelatin supports with immobilized laccase as sustainable biocatalysts for water treatment

“…The size of the beads obtained by dripping technique can be predicted by using the work of Kamaruddin et al, based on Tate's law, with Equation (1), where d T is the tip diameter (0.27 × 10 −3 m), γ is the gelatin surface tension (41 mN m −1 at 60 C), ρ is the gelatin solution density (kg m −3 ), g is the gravitational constant (9.81 m s −2 ), K LF the liquid lost factor, and K SF the shrinkage lost factor. 29,34…”

“…The determination of the gelatin solution density at 22 wt% (Table 3) and the surface tension of the gelatin/ air interface (Table 4) is achieved to use Equation (2) and Calculated with the method described by Kamaruddin et al 29 predict the bead diameter by using the method described by Kamaruddin et al 29 (see Part 2.6.). A theoretical diameter of 1.3 mm is found by using a shrinkage factor equal to 1, thus assuming that the gelatin immersion does not induce any shrinkage of the bead.…”

“…However, dripping process is a very simple process to implement; it has been widely used to prepare alginate beads for various applications. [28][29][30] This paper presents the operating conditions to design biocatalysts made by immobilized laccases onto gelatin beads for applications related to wastewater treatment. The formation mechanism of the beads is based on the coacervation of gelatin droplets in polyethylene glycol solution.…”

Release Kinetic Studies of Stevia rebaudiana Extract Capsules from Sodium Alginate and Inulin by Ionotropic Gelation

“…With respect to the cross-linking time, this variable did not have a significant effect on the encapsulation efficiency. According to Kamaruddin et al [18] during formation of capsules at higher concentrations of alginate and cross-linking agent, a stiff gel is quickly generated which can promote the release of encapsulated material from the core. e inclusion of 2% (w/w) of inulin in all treatments increased the encapsulation efficiency by the reduction of pore size of alginate beads in the presence of the filler (inulin), which prevented the leakage of the encapsulated compounds [19].…”

Diospyros cuneata Inhibition of Fusarium oxysporum: Aqueous Extract and its Encapsulation by Ionic Gelation

“…All of these results can be easily explained by taking into consideration the gel formation, which is assumed to be controlled by the diffusion of the two components involved. In this regard, the fact that the metallic cation has a smaller size than the polymer molecules means that it is mainly the cation that diffuses between the polymer chains, binding to unoccupied binding sites on the polymers [51]. A lower concentration of CaCl 2 generates less cross-linked gels, thus …”