Starch-Pectin Matrices for Encapsulation of Ascorbic Acid

Microparticles were prepared, using granular starch and pectin, for encapsulation of ascorbic acid. Three types of starch, 50% amylose corn starch, 70% amylose corn starch and type 4 resistant starch (RS4) were used in combination with high methoxyl pectin at selected ratios (2:1, 1:1, and 1:2). Microparticles were prepared by spray drying using a two-fluid nozzle. Particle size distributions were influenced by starch-pectin ratio. The largest particles were obtained with the highest starch ratio (2:1). Scanning electron microscopy showed all microparticles with similar surface indentations. The lowest encapsulation efficiencies were obtained with a starch-pectin ratio of 2:1, while there were no significant differences among different starches when starch-pectin ratios were the same. Ascorbic acid release profiles at pH 1.2 and 7.0 revealed pH-dependent behavior of the microparticles. Ascorbic acid release was influenced by both the type of starch and starch-pectin ratio. 2.