Preparation and Characterization of Propolis (Trigona sp.) Extract-loaded Chitosan Tripolyphosphate Nanoparticles

Background: Propolis contains various bioactive compounds, including polyphenols, with diverse biological properties. However, its use is hampered by poor water solubility, instability in aqueous materials and limited absorption within the body. To overcome these limitations, the development of propolis nanoparticles has been proposed. Chitosan is widely utilized to prepare chitosan-based nanoparticles. It readily undergoes gelation upon interaction with polyanions, such as sodium tripolyphosphate (TPP). Chitosan-TPP nanoparticles, serving as wall materials, are prepared through the ionic gelation method. This study aims to encapsulate propolis extract in chitosan nanoparticles (propolis extract-loaded nanoparticles, PE-NP) using chitosan of different molecular weights (low and medium molecular weight, LMW and MMW), varying chitosan concentrations and different volumes of propolis extract. Furthermore, the PE-NPs were characterized by their physical characteristics and antioxidative properties. Methods: PE-NPs were prepared using the ionic gelation method, in which chitosan and cross-linker TPP were used as wall materials (chitosan nanoparticles). The formulation was prepared by varying the molecular weight of chitosan (LMW and MMW), chitosan concentrations (0.1, 0.2 and 0.3%) and propolis extract volumes (0.1, 0.2 and 0.3 ml). The physical characteristics of PE-NP, including pH, turbidity, encapsulation efficiency, particle size, polydispersity index and zeta potential, as well as its antioxidative properties, were evaluated. Result: The resulting PE-NP revealed low encapsulation efficiency (23.937-41.192%) and pH in the range of 3.9-4.8. PE-NP also presented antioxidant capacity that polyphenolic compounds, particularly flavonoids and phenolic acids, contributed to. The suspension of PE-NP had a particle size of 350.000-488.280 nm with PDI values higher than 0.3 (heterogeneous dispersion) and positive zeta potential (39.340-48.200 mV), resulting in stable nanoparticles. The PE-NP produced has antioxidant properties, making it suitable for use as a functional ingredient in the food industry.