Electric field charge polarity triggers the organization and promotes the stability of electrosprayed probiotic cells
Panagiota Dima, P. Stubbe, Ana C. Mendes, Ioannis S. Chronakis
Abstract
The encapsulation and organization of Bifidobacterium animalis subsp. lactis (BIFIDO) probiotic cells within maltodextrin microcapsules using electrospray processing was investigated. By choosing an appropriate polarity of the DC electric field, the surface charged probiotic cells were localized either in the core or towards the surface of the capsule, as visualized using confocal microscopy. Negatively charged probiotic cells encapsulated using a negative polarity on the electrospraying nozzle, were ‘organized’ mostly in the core of the microcapsules. The organization of the cells affected the evaporation of the solvent (water) and subsequently the glass transition temperature (Tg) of the electrosprayed microcapsules. Moreover, the viability of the encapsulated cells was significantly improved for up to 2 weeks of storage at 25 °C and 35% RH, when the cells were located at the core of the microcapsules, compared to the case where the probiotics were distributed towards the surface. Overall, this study presents a novel organization process that promotes the stability of the probiotic cells.