Encapsulation of ascorbic acid in amorphous maltodextrin employing extrusion as affected by matrix/core ratio and water content

P>Ascorbic acid (AA) was encapsulated in glassy low-dextrose equivalent maltodextrin matrix by extrusion. The effects of formulation parameters, i.e., core/matrix ratio and water content were mainly investigated on T(g) of extrudate. The AA yield, AA content and water content of the products together with extrusion parameters were also determined and compared for different formulations. The T(g) of extrudates containing water content from 7.860% to 10.430% ranged from 43.17 to 27.48 degrees C, and the T(g) of extrudates which core to matrix from 1:4 to 1:8 ranged from 35.79 to 41.64 degrees C. AA yield of all extrudates is above 96%, and with increasing water content, there was a slight decrease in the AA yield. The increased water level and core/matrix ratio reduce specific mechanical energy and die head pressure. X-ray diffraction and scanning electron microscopy suggested that AA was most likely molecularly dispersed within the maltodextrin indicating the miscibility of AA and maltodextrin.