Evaluation of mass-transfer characteristics in alginate-membrane liquid-core capsules prepared using polyethylene glycol.

An alginate-membrane liquid-core capsule prepared using polyethylene glycol as a thickener was produced and the intracapsular mass-transfer characteristics of glucose and proteins were investigated. The apparent effective diffusivity of glucose into the capsule was 7.9x10(-10) m(2)/s, which is larger than that into alginate beads (6.5x10(-10) m(2)/s) and in water (6.7x10(-10) m(2)/s). Moreover, an encapsulation of strawberry cells did not decrease the mass transfer performance of glucose, in contrast to the case of immobilization in alginate beads or capsules prepared using xanthan gum. On the other hand, the apparent effective diffusivities of proteins from the capsule were smaller than those in alginate beads. In addition, the apparent effective diffusivities from the capsule decreased with the increasing concentration and molecular weight of polyethylene glycol used as a thickener during capsule preparation.