The aim of this research is to investigate the influence of the surface morphology of the calcium pectinate gel (CaPG) beads as well as the physicochemical characteristics of pectins and the CaPG beads on the adhesive properties of gels against the Gram-negative bacteria Escherichia coli and the Gram-positive bacteria Bacillus subtilis. The adhesion of the bacteria depends on the type of pectin and the surface morphology of the beads. The faster adhesion on CaPG beads appeared to be related to a lower degree of methyl esterification (DE), a higher molecular weight (Mw) and specific viscosity of the pectin and a higher gel strength. Surface roughness measurements were performed using an atomic force microscope. The beads from pectins with a higher Mw, a higher specific viscosity and a lower DE had a higher surface roughness. The surface roughness was one of the factors promoting adhesion of the bacteria onto the calcium pectinate gels. The surface morphology was observed under a scanning electron microscope (SEM). SEM images illustrated that E. coli and B. subtilis adhered on the beads with a rough surface. CaPG beads obtained from callus culture pectins can be proposed for the preparation of gels with adhesive and antiadhesive properties.
Keywords: Bacterial adhesion; Calcium pectinate gels; Pectin.
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