Characterization of oil-in-water gelatin emulsion gels: Effect of homogenization time

Abstract

Oil-in-water emulsion gels consisting sunflower oil as the internal phase and a chemically-crosslinked gelatin solution as the continuous aqueous phase were developed. The dispersion was homogenized at 60°C in a high pressure valve homogenizer at a pressure of 5000/500psi for different time periods (2, 5 or 10 min). The homogenized samples were formed into films at 5oC followed by crosslinking with genipin at room temperature. The microstructure of the gels was studied using confocal laser scanning microscopy. The results showed significant differences in the microstructure depending on homogenization time. Gel micrographs indicated a well-dispersed network of sunflower oil droplets in the gelatin matrix with a higher homogenization duration (10 min) while a less unorganized gel microstructure was evident at shorter homogenization times (2 and 5 min). Gels were also characterized using colourimetric analysis. Puncture tests of the gels were tested to establish their mechanical stability. The gels prepared with 10 min homogenization exhibited the highest puncture strength (0.23±0.20 MPa) (p<0.05). These results demonstrated that gelatin gels homogenized for longer periods were more stable, thus expanding their range of possible biomedical applications.