Encapsulating probiotics with an interpolymer complex in supercritical carbon dioxide : the CSIR at 60

Traditional encapsulation methods in fortified foods and drug delivery applications present difficulties for 'actives', such as probiotics, sensitive to exposure to water, solvents, heat or oxygen, where 'active' refers to a material, chemical or organism that has some potential benefit when consumed. In this paper we present a novel encapsulation technology, based on interpolymer complex formation in supercritical carbon dioxide, which avoids such exposure during the encapsulation process. The method was used to encapsulate indomethacin and Bifidobacterium longum in a poly(vinyl pyrrolidone)-poly(vinyl acetate-co-crotonic acid) interpolymer complex. Polymer complexation was confirmed by Fourier Transform infrared and moisture absorption studies. Polymer plasticization and release of encapsulated probiotics were studied with scanning electron microscopy. It was shown that the encapsulation matrix is stable at low pH, but disintegrates at higher pH, triggering release of the encapsulated material. The technology could find application in encapsulation of sensitive actives in the food and pharmaceutical industries.