Alginate/pectin aerogel microspheres for controlled release of proanthocyanidins

Biopolymer aerogel microspheres based on alginate and pectin, were fabricated by crosslinking with divalent cation (Ca2+) and sol-gel method followed by freeze-drying process. The morphology of the alginate/pectin aerogel microspheres examined by scanning electron microscopy indicated that the porosity and pore size increased with the increasing pectin ratio in the aerogels. The aerogels with higher alginate content presented higher stiffness, while the aerogels with higher pectin ratio exhibited the significantly (p < 0.05) higher water solubility and equilibrium moisture. Furthermore, proanthocyanidins were encapsulated in these aerogel microspheres and showed a good controlled release, as well described by first-order and Korsmeyer-Peppas models. The radical scavenging activity and ferric reducing antioxidant power results indicated that the encapsulated aerogel microspheres with higher pectin content had a stronger antioxidant activity.