Comparison of emulsifying characteristics of different macromolecule emulsifiers and their effects on the physical properties of lycopene nanoemulsions

Abstract

A considerable research effort is focused on using biological macromolecules as emulsifiers to prepare nutraceuticals-loaded nanoemulsions. In this study, the emulsifying characteristics of three macromolecular emulsifiers: octenyl succinate anhydride modified starch (OSA modified starch), whey protein isolate (WPI) and sodium caseinate (SC), and physical property of lycopene-loaded nanoemulsions prepared with these emulsifiers were compared. The emulsifying characteristics of the three emulsifiers, in the concentration range studied, showed near Newtonian fluid characteristics. OSA modified starch reduced interfacial tension in the oil–water systems more significantly than the protein emulsifiers, and OSA modified starch and SC showed greater emulsifying activity than WPI. The optimum emulsifier concentrations for preparation of lycopene nanoemulsions were shown to be 30, 1 and 2% (w/w) for OSA modified starch, WPI and SC, respectively. Results of physical properties showed that OSA modified starch and SC were superior to WPI at forming small droplets (125 ± 5.11, 186 ± 1.76 and 250 ± 8.21 nm, respectively) and showed greater lycopene encapsulation efficiency (77.3, 79.6 and 65.2% (w/w), respectively). Furthermore, based on the transmittance map and calculated instability index using the LUMISizer, OSA modified starch and SC-stabilized nanoemulsions were more stable than WPI-stabilized nanoemulsions. These results show that emulsifier characteristics have a significant impact on the formation and stability of nanoemulsions.