Nanoencapsulation of black seed oil by coaxial electrospraying: characterisation, oxidative stability and <i>in vitro</i> gastrointestinal digestion

Abstract

Summary In this study, black seed oil‐loaded zein nanoparticles were produced via coaxial electrospraying. Nanoparticles obtained under optimised conditions had a uniform morphology with a mean diameter of 136 nm and a core–shell structure verified by confocal laser scanning microscope. The encapsulation efficiency of the oil in nanoparticles ranged from 65.3 to 97.2%. The peroxide value of oil in nanoparticles with high encapsulation efficiency was approximately three times lower than unencapsulated oil when stored at 60 °C for 55 days. The totox value of the encapsulated oil in nanoparticles stored at 25 °C was lower than the critical totox value of 30. The amount of thymoquinone released from encapsulated oil was low at the end of the gastric digestion, but the bioaccessibility of thymoquinone from encapsulated oil increased during intestinal digestion compared with free oil. These results demonstrated the successful nanoencapsulation of black seed oil with the improved oxidative stability due to the coaxial structures formed. Black seed oil‐loaded zein particles may have the potential to expand the use of black seed oil as a functional ingredient for food systems.