Enhanced Antibacterial Activity of Chitosan Nanoparticles Encapsulated in Annatto Seed Extract Against Meat-Borne Bacterial Contamination
Year: 2025
Type: article
Abstract: Active compounds from annatto seeds were extracted using alcoholic solvents (ethanol) and synthesized with chitosan nanoparticles (CsNPs) to analyze their properties and antibacterial activity. The annatto seed extracts yielded 4.3% of the powder. The CsNPs were synthesized via ion coagulation which is simple and does not require harsh chemicals. The particle sizes ranged from 39.48 to 43.48 nm. UV-Vis analysis showed an absorption peak at 214 nm for the annatto extract/ chitosan nanoparticles (A Ex/CsNPs), indicating their formation by the surface plasmon resonance (SPR) phenomenon. The presence of functional groups such as alcohols, phenols, and alkaloids in the extract and nanoparticles was confirmed. Heightened intensity of the amide peak of 1580–1650 cm⁻¹ in the nanoparticles was also shown, indicating the interaction of the bioactive compounds with chitosan. The nanoparticles exhibited two peaks at angles of 19.9° and 23.7°, confirming their crystalline structure. Lower peak intensity was observed upon incorporation of the extract, indicating increased flexibility of the polymer chains. Microscopic images revealed nanoparticles of sizes 39.48–43.48 nm with rough surfaces, which may enhance interaction with biological targets. The alcoholic extract (A Ex) showed activity against bacteria such as E. coli and S. aureus at a minimum inhibitory concentration (MIC) of 1.17 mg/ml, while the A Ex/CsNPs recorded higher activity of 92.08 μg/ml with three replicates. This activity is attributed to phenolic compounds, flavonoids (antioxidants), and alkaloids that weaken bacterial membranes, and disrupts their cellular functions. It can be concluded that nanoparticles loaded with annatto extract have superior antibacterial activity compared to the crude extract due to their greater stability and surface area. These findings offer new avenues for applications in the pharmaceutical and food industries as natural alternatives to synthetic preservatives
Authors: Z. Altaee, L. Alzubaidi, A. Al-Rubeii
Institution: University of Baghdad
Language: English
Subfield: Biomaterials
Field: Materials Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7118387992
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