Abstract: The in vitro digestion characteristics of lycopene nanoemulsions stabilized with three different emulsifiers: octenyl succinic anhydride (OSA)-modified starch, whey protein isolate (WPI) and sodium caseinate (SC) were studied. The results showed that the droplet size, zeta potential and microstructure of the nanoemulsions during digestion mainly depended on emulsifier type. Each nanoemulsion was digested in both simulated gastric and intestinal fluid, leading to droplet aggregation, increased emulsion droplet size and minimal zeta potential. The release rate of free fatty acid from these lycopene nanoemulsions followed the decreasing order: OSA-modified starch (92.25%) > SC (86.53%) > WPI (79.88%), which was higher than that (48.7%) of the control group. This indicates that the incorporation of lycopene into nanoemulsions could improve its digestion characteristics effectively. The nanoemulsions stabilized with OSA modified starch showed higher lycopene bioavailability (25.60 ± 3.08)% than those stabilized with protein emulsifiers.

Key words: macromolecular emulsifier, lycopene, nanoemulsion, in vitro simulated digestion