Mechanical strength of calcium alginate gel beads

Abstract

To date, there is no survey relates the relationship between these process variables such as gelation time of alginate beads, mechanical strength, size and shape of the beads, concentration of gelling agent and alginate and etc. This study aims to investigate the correlation between different process variables and to determine the mechanical strength of gel beads produced under different ranges of the process variables. Hence, a mathematical model to correlate process variables and mechanical strength of the gel beads can be developed. In this project, calcium alginate gel beads were produced using extrusion dripping method with different ranges of process variables such as gelation time (1, 5, 10, 15, 20 and 30 minutes), diameter of nozzles (0.8 mm, 1.1 mm and 2.5 mm), concentration of calcium chloride (0.1 M and 0.15 M) and concentration of alginate (1 %, 2 %, 3 % and 4 % w/v). Gel beads produced in different conditions were tested by using deformation percentage model. Morphology and changes of bead size were analysed by image analyser. The average mean and standard deviation of the data was calculated by using 1-way ANNOVA with Minitab, USA. Deformation percentage and Young’s Modulus were calculated by using related formula. From the analysis, the results showed that bead diameter was directly proportional to gelation time and alginate concentration and inversely proportional to calcium chloride concentration. Besides, deformation percentage was inversely proportional to alginate and calcium chloride concentrations. It was found out that deformation percentage increased when gelation time was longer than 10 minutes. Deformation percentage decreased when gelation time was shorter than 10 minutes. The graph of correlation between Young’s Modulus and bead diameter in low alginate concentration followed power law. Mathematical model developed in high alginate concentration was positive.