Influence of composition on the internal diffusion mechanism of pectin-starch gel beads

Pectin is a hydrocolloid commonly used as a wall material for encapsulation, meantime using a filler such as starch can improve the retention in the matrix and control the release in specific places. Formulations of pectin and starch were evaluated for bead production by ionic gelation technique using dripping and jet cutter methods. In addition, beads were dried in a fluidized bed and rotating drum at 50 degrees C. The mean diameter, mechanical strength, yield, moisture content, the morphology of wet and dry beads, and rehydration behavior were evaluated. Furthermore, the pomegranate extract (PE) encapsulation efficiency and release in water were measured. The beads with 2.85% solids content of which 70% are pectin and 30%, waxy corn starch proved to be technologically viable and were satisfactorily dried in a fluidized bed, while on a rotating drum, drying was not efficient. Compared with pure pectin, the pectin-starch beads showed a spherical shape, smoother and more homogeneous with greater mechanical strength and greater water absorption capacity after drying in a fluidized bed. The conventional encapsulation of PE added to biopolymer solutions showed low efficiency (4.7%-43.7%) and the release velocity was higher for drip beads (similar to 70%).