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Alginate capsules for encapsulating probiotics were synthesized under mild conditions without using harmful chemicals. When alginate capsules were synthesized using glucono-δ-lactone while suppressing the rapid pH drop of the inner water phase, it was possible to encapsulate living lactic acid bacteria. It was also found that coating the alginate capsule surface with chitosan improved the protective effect of the encapsulated lactic acid bacteria. Furthermore, culturing the encapsulated bacteria inside the capsules increased the number of living bacteria to meet the minimum recommended level for probiotic effect. Finally, we demonstrated that almost all encapsulated bacteria were released within 60 minutes in simulated intestinal fluid. From the above, it was suggested that the chitosan-coated alginate capsules synthesized in this study can be used as capsules for encapsulating probiotics. [ABSTRACT FROM AUTHOR]

Alginic acid from seaweed and chitosan derived from shrimp and crab shells are well known as abundant biopolymers of marine origin. Alginic acid as a polyanion and chitosan as a polycation produce a polyelectrolyte complex (PIC) by ionic crosslinking. So far, PIC has been prepared by alternate lamination or casting methods. In this study, a novel continuous preparation method of PIC was demonstrated with an extruder and a hot press. It was confirmed that homogeneous PIC sheets were prepared conveniently. Moreover, by adding various plasticizers it was shown that mechanical properties of PIC were controllable in a range of hard and soft materials. [ABSTRACT FROM AUTHOR]

Sugar-sensitive microcapsules containing insulin were prepared by a layer-by-layer (LbL) deposition of alginic acid (AGA) and phenylboronic acid-modified poly (allylamine) (PBA-PAH) on the surface of a calcium carbonate (CaCO3) microparticle in which insulin had been embedded, followed by dissolution of the CaCO3 core. The microcapsules thus prepared were stable at pH 7.0-9.0. In the presence of 10-100 mM fructose or glucose, the release of insulin was significantly enhanced depending on solution pH and sugar concentration. The sugar-triggered release of insulin was explained on the basis of decomposition of the microcapsules, which in turn was caused by competitive binding of added sugar to the phenylboronic acid moieties in the LbL film. [ABSTRACT FROM AUTHOR]