A modified 3-fluid nozzle spray drying approach for co-encapsulation of iron and folic acid

Micronutrient deficiency, particularly iron and folic acid, is a serious global concern and fortification of these micronutrients through food is the most effective strategy. However, the limitations of the direct incorporation of ferrous iron into foods demand an approach of encapsulation. The present work reports a novel approach for encapsulation of iron and folic acid along with ascorbic acid into multilayer encapsulates of whey protein and ethyl cellulose using a modified 3-fluid nozzle spray drying (3FN SD). Formation of ethyl cellulose as the shell over whey protein core resulted in an improvement in the color (increase in L* value) and flowability (from poor to fair) compared to the ones prepared by conventional 2-fluid nozzle spray drying (2FN SD). Samples with 1% and 2% ethyl cellulose showed better flowability compared to the other two samples. 15WP-2EC sample reported maximum encapsulation efficiency for iron (86.6 +/- 4.3%) and folic acid (89.92 +/- 2.07%). Changes in the surface composition in terms of amine and aliphatic carbon bonds confirm the formation of multilayer encapsulates by 3FN SD. The effect of ethyl cellulose shell formation is evident on the release of iron and folic acid which resulted in a relatively slower release compared to the encapsulates prepared by 2FN SD. 15WP-2EC sample despite being prepared by 3FN SD showed a higher release of iron and folic acid owing to improper shell formation which can be confirmed by surface morphology. Based on the observations of this work, multilayer encapsulates 15WP-0.5EC and 15WP-1EC showed improvement in appearance, flowability, and sustained release properties and therefore can be recommended for application in food systems.