Encapsulation of lactase (β-galactosidase) into κ-carrageenan-based hydrogel beads: Impact of environmental conditions on enzyme activity

• Encapsulation increased lactase activity over a range of pH and temperature.
• Increased activity was mainly attributed to high potassium levels in hydrogels.
• Potassium ions are known to stabilize lactase structure and enhance activity.
• During storage the enzyme had a tendency to leak out of the hydrogel beads.

Encapsulation of enzymes in hydrogel beads may improve their utilization and activity in foods. In this study, the potential of carrageenan hydrogel beads for encapsulating β-galactosidase was investigated. Hydrogel beads were fabricated by injecting an aqueous solution, containing β-galactosidase (26 U) and carrageenan (1 wt%), into a hardening solution (5% potassium chloride). Around 63% of the β-galactosidase was initially encapsulated in the hydrogel beads. Encapsulated β-galactosidase had a higher activity than that of the free enzyme over a range of pH and thermal conditions, which was attributed to the stabilization of the enzyme structure by K+ ions within the carrageenan beads. Release of the enzyme from the beads was observed during storage in aqueous solutions, which was attributed to the relatively large pore size of the hydrogel matrix. Our results suggest that carrageenan hydrogel beads may be useful encapsulation systems, but further work is needed to inhibit enzyme leakage.