Formulation and Drying of Alginate Beads for Controlled Release and Stabilization of Invertase

SANTAGAPITA, PATRICIO R.; MAZZOBRE, M. FLORENCIA; BUERA, M. PILAR

BIOMACROMOLECULES

AMER CHEMICAL SOC

Año: 2011 vol. 12 p. 3147 - 3155

1525-7797

Several alternatives to the conventional alginate beads formulation were studied for encapsulation of invertase. Pectin was added to the alginate/enzyme solution while trehalose and ß-cyclodextrin were added to the calcium gelation media. The effect of composition changes, freezing, drying methods (freeze, vacuum or air drying) and thermal treatment were evaluated on invertase stability and its release kinetics from beads. The enzyme release mechanism from wet beads depended on pH. The addition of trehalose, pectin and ß-cyclodextrin modified the bead structure, leading in some cases to a release mechanism which included the relaxation of the polymer chains, besides Fickian diffusion. Enzyme release from vacuum dried beads was much faster than from freeze dried beads, probably due to their higher pore size. The inclusion of ß-cyclodextrin and especially of pectin prevented enzyme activity losses during bead generation, and trehalose addition was fundamental for achieving adequate invertase protection during freezing, drying and thermal treatment. Present results showed that several alternatives such as drying method, composition, as well as pH of the relese medium can be managed to control enzyme release.