γ-polyglutamic acid–alginate hydrogel beads for encapsulation and controlled release of folic acid: Application in functional beetroot jelly

Folic acid (FA), an essential yet highly unstable micronutrient, was successfully encapsulated within γ -polyglutamic acid ( γ -PGA) and sodium alginate hydrogel beads using an extrusion technique into CaCl 2 solution. The developed microbeads demonstrated potential for optimized controlled delivery in nutraceutical applications. In this study, varying concentrations of γ- PGA (0–0.75 %) were incorporated with 2 % sodium alginate to serve as the wall material for folic acid encapsulation. Among the formulations, beads containing 0.5 % γ- PGA exhibited superior characteristics, including uniform and rigid morphology, high encapsulation efficiency, enhanced resistance under simulated gastric conditions (pH 2), and improved release behavior at intestinal pH (7.5). The beads were comprehensively characterized for physicochemical properties such as pH, particle diameter, swelling index, water activity, and encapsulation efficiency, along with structural and thermal analyses using SEM, TGA, and XRD techniques. The optimized bead formulation (0.5 % γ -PGA) was further incorporated into agar-based beetroot jellies (0.8 %) and evaluated for physico-functional properties and sensory attributes. This study demonstrates the efficacy of γ-PGA as a functional biopolymer in stabilizing sensitive bioactive compounds such as folic acid, thereby improving their bioavailability, structural integrity, and consumer acceptability. The findings further indicate significant potential for developing scalable, value-added nutraceutical and functional food products, particularly for children and pregnant women, to meet their elevated folic acid requirements.