Microencapsulation of selenium by spray-drying as a tool to improve bioaccessibility in food matrix

Se in the form of sodium selenite was microencapsulated by spray - drying and added to a food matrix (yogurt) to study the potential improvement of its bioaccessibility. Yogurt samples were also supplemented with Se in free salt form. Se-loaded microparticles were successfully prepared by spray-drying with production yields above 70%. The supplementation of yogurt with Se in the form of free sodium selenite had a low effect on improving the bioaccessibility of this micronutrient (1%). In turn, Se microencapsulation with mannitol or mannitol/gastro-resistant polymer (Eudragit (R)) had a strong impact on bioaccessibility results. After the gastric phase, Se bio-accessibility reached values of 21 and 40% for the microencapsulated formulations, respectively. This percentage rose to 55% at the end of intestinal phase, showing no differences between both formulations. Our results show the relevance of microencapsulation as an effective tool to improve the bioaccessibility of micronutrients when they are used in food supplementation.