Microencapsulation by spray drying of emulsified green coffee oil with two-layered membranes
2014
Carvalho, A.G.S. | Silva, V.M. | Hubinger, M.D.
The aim of this work was to produce microparticles of green coffee oil by spray drying using emulsions stabilised by lecithin and chitosan through electrostatic layer-by-layer deposition technique. The emulsions were prepared using only corn syrup and the modified starch Hi-Cap 100 and the combination of the corn syrup with the Hi-Cap 100 or modified starch Snow-Flake at a 50:50 ratio. The feed emulsions were characterised for stability, droplet size, ζ-potential and optical microscopy. The microparticles obtained after the drying process were characterised regarding encapsulation efficiency, moisture content, water activity, particle size distribution, microstructure, in vitro sun protection factor and lipid oxidation by Rancimat. The emulsions stabilised by lecithin–chitosan were highly stable, with droplet size ranged from 1.35 to 3.70μm and ζ-potential varied from −2.24 to +40.40mV. All microparticles presented high encapsulation efficiency values, above 86%. The microparticles produced with the modified starches showed spherical shape without cracks or holes and those produced with only corn syrup showed some holes and cracks that caused lower oxidative stability. Microparticles produced with Hi-Cap 100 and corn syrup/Hi-Cap 100 stabilised by lecithin–chitosan exhibited the highest oxidative stability among the microparticles. The sun protection factor of microparticles ranged from 1.52 to 2.45, close to the pure green coffee oil.
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