Abstract
The agricultural waste peels have been considered as an ecological burden on society. Therefore, this study focuses on the use of Citrus sinensis L. peel oil and nanoemulsion as an antifungal agent, along with the effect of high-intensity ultrasound on the chemical constituents and the activity of the oil nanocapsules. The chemical composition was determined using gas chromatography/mass spectrometry. A total number of 20 components were identified, representing 99.65%, of the total essential oils, while 14 and 6 compounds were identified in nanoemulsions and dried peels accounting for 90.61 and 74.21%, respectively. Limonene was predominant in all investigated samples but with a quantitative difference, while the encapsulation leads to identify other predominates like linalool, carveols, mentha-2,8-dienol, carvone, and limonene aldehyde. Meanwhile, the sun-dried technique is negatively affected the active constituents of the oil. The mean particle size of the Citrus sinensis L. nanoemulsion was 97.22 nm, with a poly dispersibility index (PDI, 0.016), while the zeta potential value was -16.31 ± 2.54 mV, which is consistent with the pH 5.18. The viscosity of the prepared nanoemulsion was 1.37 mPa/sec. showing non-significant differences, and higher stability formula. The transmission electron microscope showed that the nanoparticles were spherical, uniformly distributed, discrete, and non-aggregated. A varying degree of antifungal activity of both Citrus sinensis L. peel essential oil and nanoemulsion was observed. Citrus sinensis L. peel essential oil exhibited antifungal activity against A. niger, A. ochraceus, Fusarium spp., and Penicillium spp. Meanwhile, nanoemulsion displayed lower antifungal activity, against A. flavus, A. niger, and A. ochraceus. The incorporation of Citrus sinensis L. peel essential oil into nanoemulsions provided an improved method for delivering this oil while retaining its bioactivity.