Background and Objectives: Pomegranate seed oil contains significant amounts of estrols such as β-sitosterol, stigmasterol, campesterol, and also, 𝛼, 𝛽 and 𝛾 tocopherols. The object of this article is encapsulation of pomegranate seed oil in zein nanoparticles and investigation of the stability of these encapsulated functional compounds in food systems model (such as acidic beverages) and passing under gastric simulating conditions and release in the intestinal tract.

Materials and Methods: Zein was chemically cross-linked with citric acid in the presence of sodium hydroxide as catalyst. Water was then used to desolvate the zein and generate core-free or pomegranate seed oil-loaded particles.

Results: The mean sizes of the particles obtained from non-cross-linked and cross-linked zeins were 350 and 246 nm, respectively. Cross-linking of the particles resulted to increase in the oil encapsulation efficiency from 87% to 95%. Scanning electron microscopy revealed a spherical morphology for particles. Fourier transform infrared (FTIR) spectroscopy confirmed the occurrence of chemical linkages between citric acid and zein. Also it was found that oil entrapment inside the zein particles was merely physical.

Conclusion: The results showed that citric acid in the presence of NaOH as alkaline catalyst can be used successfully for production of cross-linked zein.

Keywords: Zein nanoparticles, Citric acid, Cross-linking, Desolvation, Pomegranate seed oil