Pectin-glycerol gel beads: Preparation, characterization and swelling behaviour

Low methyl-esterified pectin (AU701) was found to form gel beads with glycerol. Wet AU701-glycerol gel beads exhibited similar diameter and hardness compared to the AU701-Ca gel beads, prepared by ionotropic gelation with Ca²⁺ and used for comparison. The morphology of dry pectin gel beads determined by scanning electron microscopy revealed that the beads exhibited rough and grooved surface. The AU701-glycerol gel beads absorbed more grams of water than AU701-Ca gel beads (12.2 g vs 3.9 g per 1 g of the beads). Rheological properties and hardness of the AU701-glycerol gel beads improved with the increase of the pectin/glycerol ratio. Swelling behavior of the AU701-glycerol gel beads was determined after sequential incubation in simulated gastric (SGF) and intestinal (SIF) fluids. The AU701-glycerol gel beads swelled in SGF to a greater extent and revealed higher stability in SIF than the gel beads cross-linked by Ca²⁺.