Smart porous microparticles based on gelatin/sodium alginate polyelectrolyte complex

Porous microparticles of different sizes were prepared by polyelectrolyte complexation of biopolymers gelatine A and sodium alginate for microencapsulation of food bioactives. The optimum pH and ratio between the polymers sodium alginate and gelatine for maximum complexation was found as 3.7 and 1:3.5 respectively. Effect of various factors like amount of surfactant, concentration of polymer and crosslinker on the formation, size and porous/nonporous nature of the microparticles were investigated. The particles’ diameter on swelling at pH = 7.4 was twice that at pH = 1.2 indicating the pH responsiveness. These microparticles were used as carrier for ascorbic acid. The surface morphology and sizes of the microparticles were investigated by scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FTIR) study indicated the formation of polyelectrolyte complex between gelatine and sodium alginate and successful encapsulation of ascorbic acid into the microparticles. The microparticles were further characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) study.

► Synthesis and characterization of gelatin–sodium alginate microparticles is described.
► The microparticles were tailored for different size and porous/nonporous morphology.
► The microparticles showed pH responsiveness.
► Ascorbic acid was successfully encapsulated in microparticles.
► The microparticles promises great potential for future for food applications.