Microencapsulation of oil droplets using cold water fish gelatine/gum arabic complex coacervation by membrane emulsification

Food grade sunflower oil was microencapsulated using cold water fish gelatine (FG)-gum arabic (GA) complex
coacervation in combination with a batch stirred cell or continuous pulsed flow membrane emulsification system.
Oil droplets with a controllable median size of 40-240 ?m and a particle span as low as 0.46 were generated
using a microengineered membrane with a pore size of 10 ?m and a pore spacing of 200 ?m at the shear stress
of 1.3-24 Pa. A biopolymer shell around the oil droplets was formed under room temperature conditions at
pH 2.7-4.5 and a total biopolymer concentration lower than 4% w/w using weight ratios of FG to GA from
40:60 to 80:20. The maximum coacervate yield was achieved at pH 3.5 and a weight ratio of FG to GA of
50:50. The liquid biopolymer coating around the droplets was crosslinked with glutaraldehyde (GTA) to form
a solid shell. A minimum concentration of GTA of 1.4 M was necessary to promote the crosslinking reaction
between FG and GTA and the optimal GTA concentration was 24 M. The developedmethod allows a continuous
production of complex coacervate microcapsules of controlled size, under mild shear stress conditions, using
considerably less energy when compared to alternative gelatine types and production methods.