Multilayered composite-coated ionically crosslinked food-grade hydrogel beads generated from algal alginate for controlled and sustained release of bioactive compounds

Hydrogels have gained interest as sustained-release matrices partly because of their high biocompatibility and ease of preparation. Their wide application has, however, been limited by their poor mechanical strength and their lack of tunability in the performance of bioactive agent delivery. By using the lake substratum as a gel property modifier, in combination with the use of the surface coating approach and the ionic gelation technique, hydrogel beads are generated from algal alginate for controlled and sustained release of bioactive compounds. Both the acute and chronic toxicity of the beads are found to be negligible in 3T3 fibroblasts. The capacity of the beads in retaining the activity of the loaded agent is verified by the negligible change in the action of the loaded compound on foodborne bacteria (viz., Staphylococcus aureus and Escherichia coli). Along with the high flexibility provided by the adopted method in the choice of coating materials, our beads extend the limitations of conventional ionically crosslinked gel systems, and show high potential for applications in functional food development, nutraceutical delivery, and pharmaceutical formulation.