Green synthesis optimization and characterization of selenium nanoparticles using aqueous extract of peel bitter orange (Citrus aurantium)

Abstract

Background: Bitter orange is a citrus fruit rich in bioactive compounds such as flavonoids, which provide antioxidant and antimicrobial properties. Often, its peel is used in the food industry. This study demonstrated that dried bitter orange peel extract is a reducing agent for the rapid and straightforward synthesis of nano-sized selenium nanoparticles. 

Objective: This study aimed to develop sustainable technology for synthesizing selenium nanoparticles from the aqueous extract of bitter orange peels, which were used as reducing and capping agents.

Results: The results of nanoparticles, which were studied in this experiment using UV-Visible spectroscopy, displayed that surface Plasmon resonance was centered at 289 nm. This experiment also concluded an absorption of 1.098. The FT-IR spectroscopy observed the presence of ascorbic acid, phenolic compounds, and a hydroxyl group. X-ray diffraction (XRD) analysis revealed a spherical crystal structure. The highest diffraction intensity was observed at the 100-crystal plane at a 2θ angle of 27.691°. The peak width at this position corresponded to a crystallite size of approximately 18 nm. This concluded that all particles were within the nanoscale range. The scanning electron microscopy (FE-SEM) results concluded that the nanoparticles were homogeneous in size and, after preparing a selenium solution, the crystal ball diameter ranged between 29.24  and nd 59.14 nm. The treatments coated with composite and straightforward carrageenan films developed a distinctive texture and aroma and maintained their shape, color, and overall acceptability throughout the refrigeration period.

Novelty: This study demonstrates that using bitter orange peels may be a natural source of bioactive compounds such as phenols and flavonoids. Furthermore, selenium particle preparation using green, environmentally friendly methods within a natural polymer matrix of carrageenan may offer vigorous antioxidant activity. This produces nano-films, which may serve as innovative/active packaging materials that maintain the quality and safety of functional food products. This enhances the biological value of active ingredients while improving their biological efficiency through the nano system. Recycling fruit waste of bitter orange peels and using renewable natural materials like carrageenan offers additional green technologies without using solvents or harmful compounds. This will propel the development of sustainable goals in clean production and waste reduction.

Conclusion: Bitter orange peel extracts act as reducing agents for the rapid and straightforward synthesis of nano-sized selenium nanoparticles. This provides sustainable and economic benefits to produce functional foods.

Keywords: bitter orange peel, selenium oxide, carrageenan, green synthesis, particle characterization, Food processing (burger).