Study on the Formation and Stability Properties of Nanoemulsions with Octenyl Succinic Anhydride Modified Starch

In the present study, octenyl succinic anhydride modified starch (OSA-starch) nanoemulsion was prepared and characterized, with varying OSA-starch concentration (0.52.0 wt%), homogenization pressure (5,00020,000 psi), and co-emulsifier (lecithin) concentration (1.03.0 wt%). The fat globule size in the emulsion decreased with increasing OSA-starch concentration and homogenization pressure [(0.5 wt% OSA-starch: 245.1 nm 2.0 wt% OSA-starch: 207.2 nm), (5,000 psi: 247.3 nm 20,000 psi: 207.2 nm)]. However, in a 2.0 wt% OSA-starch emulsion containing different concentrations of the co-emulsifier lecithin, the size of fat globules showed a dose-dependent decrease with increasing lecithin concentration (1.0 wt%: 221.7 nm 3.0 wt%: 153.2 nm). We further evaluated the storage stability of the emulsion by conducting a storage experiment at room temperature for 4 weeks. When OSA-starch was used alone, the storage stability of the emulsion was low, especially at a low added concentration (0.5 wt% concentration: 237.1 nm at initial stage 384.27 nm after 4 weeks). However, emulsions prepared using lecithin (2.0 wt% OSA-starch, 5.0 wt% MCT oil, 20,000 psi) showed no significant change in the size of fat globules according to the storage period at all lecithin concentrations. This could be attributed to increased steric force and electrostatic repulsion between the fat globules by forming a strong film on the fat globule surface using the co-emulsifier.