Nanostructured lipid carriers for enhanced bioaccessibility of thymoquinone and its application in pure and sparkling apple juice fortification

This research investigated nanostructured lipid carriers (NLC) as a delivery system for thymoquinone-rich black seed oil (TQBSO). The objectives were to determine the in vitro bioaccessibility and release profile of the NLC containing TQBSO (NLC-TQBSO) and assess its physicochemical stability when incorporated into pure and sparkling apple juice and carbonated water over 28-day storage by monitoring pH, turbidity, particle size, TQ concentration, and browning index. The results showed that NLC-TQBSO was produced with small particle size, spherical and smooth topography, low zeta potential, and low polydispersity index. NLC improved TQ's bioaccessibility and release profile in simulated digestion phases, which were characterized by a more sustained release than emulsion and nanoemulsion. The stability evaluation of beverages fortified with 10% NLC-TQBSO revealed that the NLC-TQBSO remained physically stable, particularly in the juice and sparkling juice, confirmed by the low turbidity and small particle size until the end of the storage period. The interaction between storage duration and condition significantly affected the remaining TQ in the fortified beverages, where the most rapid TQ degradation occurred under light exposure. NLC-TQBSO fortification prevented the browning reaction. These results could be a scientific foundation for further development in broader application of NLC for functional beverages. • The nanostructured lipid carriers containing thymoquinone-rich black seed oil (NLC-TQBSO) were prepared. • NLC-TQBSO showed a controlled release profile and higher in vitro bioaccessibility than emulsion- and nanoemulsion-TQBSO. • NLC-TQBSO fortified juices remained physically stable, with minimal changes in turbidity and particle size during storage. • Thymoquinone in all the fortified beverages deteriorated rapidly under light exposure.