Comparison of different methods for release of Bifidobacterium longum Bb46 from the poly(vinylpyrrolidone)-poly(vinylacetate-co-crotonic acid) interpolymer complex matrix, and the effect of grinding on the microparticles

摘要

Bifidobacteria have been efficiently encapsulated in poly(vinylpyrrolidone)-poly(vinylacetate-co-crotonic acid)(PVP:PVAc-CA) interpolymer complex formed in scCO2. Research indicated that this method improves thestability of encapsulated bacteria in simulated gastrointestinal fluids in vitro. However, further analysis indicatedrelease of lower numbers of encapsulated bacteria from the encapsulating matrix. The aims of this study were todetermine a method that would release high numbers of bacteria from the PVP:PVAc-CA interpolymer complexmatrix microparticles, and furthermore, to determine the effects of milling on the morphological properties of themicroparticles. Three release methods, namely sonication, homogenization in a stomacher and incubation insimulated intestinal fluid (SIF) were compared. Released viable bacteria were assayed using plate counts. Viablebacteria released using a stomacher were three orders of magnitude higher than those released by incubation and anorder of magnitude higher than those released using sonication. SEM indicated no negative effects such as exposureof encapsulated bacteria on the matrix due to milling of product. Homogenization in a stomacher is the mostefficient method for releasing bacteria from the PVP:PVAc-CA interpolymer complex matrix. Particle size of thePVP:PVAc-CA microparticles encapsulating bacteria can be reduced further by grinding, without exposing theenclosed bacteria.