Development of Multi-Cellular Gel Droplets Using κ-Carrageenan Composited Alginate for Controlled Release of Hydrophobic Components

Biopolymer gels have considerable potential because of their ability to encapsulate, protect, and release bioactive components. In the present study, kappa-carrageenan composited alginate gel beads were prepared and tested for use as potential delivery vehicles for the encapsulation and controlled release of capsanthin, an antioxidant ingredient contained in red pepper. By varying the weight ratio of kappa-carrageenan, as well as the concentration or type of the crosslinking agent and outer organic phase, different sustained release characteristics of capsanthin from kappa-carrageenan composited alginate gel beads were obtained. In the case of sustained release experiments using kappa-carrageenan composited alginate gel beads, for a mass ratio of kappa-carrageenan in the polymer (1wt%) of 50%, the sustained release ratio for a predetermined time was suppressed to about 80% of the maximum value for Ca2+ and about 40% for K+ at 120 min. When the KCl concentration of the crosslinking agent for gelation was increased, the start time of the sustained release was delayed. These were discussed on surface structure of the gel beads by scanning electron microscopy. Also, as the hydrophobicity of the outer organic phase increased, the beads shrank in volume, and the sustained release ratio decreased. These results indicate that the encapsulation of bioactive components using kappa-carrageenan composited alginate polymer could provide an effective means for the controlled release of capsanthin.