BIOPOLYMER-BASED STRATEGIES TO IMPROVE DELIVERY PROPERTIES OF B12 IN ALGINATE GELS: ROLE OF PROTEIN FILLERS AND CHITOSAN

Alginate is a natural biopolymer widely used for enteric delivery of bioactive, due to its biocompatibility, low toxicity, and mild gelation abilities. The encapsulation efficiency of bioactive compounds in alginate matrix is straight related to the gel pore size that can be tuned using fillers. Herin, we propose a new approach for improving the encapsulation and delivery of cyanocobalamin (vitamin B12) in alginate gels by filling the network with different sources of proteins. Vegetable fillers (rice and potato proteins) were compared to whey protein fillers on enhancing the physical and delivery properties of alginate particles formed by ionotropic gelation. The effect of filler type on the stability of the particles at different pH values, as well as on the encapsulation efficiency of cyanocobalamin and its release was compared to traditional alginate-chitosan complexation. The encapsulation efficiency of pure alginate gels improved from 16% to 86% with rice protein filler. Although rice and potato protein-filled gels presented similar release profiles, they diverge in mechanical properties and delayed the bioactive release in comparison to whey protein-filled gels. The complexation with chitosan affected the vitamin release and increased particle stability at pH 3.0. Alginate beads filled with vegetable proteins and complexed with chitosan reached 93% of vitamin encapsulation. These results highlight the improvement of alginate matrix based on vegetable proteins and expand its uses as delivery systems of hydrophilic bioactive compounds, such as vitamin B12.