Background: The identification and quantification of quercetin in tropical fruits could be an
incentive to consume these fruits as health promoters. The purpose of this study was to identify and
quantify the levels of quercetin in tropical fruits extracts, and then select the extract with the highest
levels of quercetin, in order to synthesize nanoparticles using cashew gum as core material.
Method: The detection and quantification of quercetin of pulps and by-products of tropical fruits were
performed using HPLC. The extraction of cashew gum (core material) was performed in order to synthesize
the particles, using the extract that presented higher content of quercetin. The nanoparticles were
submitted to characterization (particle size, X-ray diffraction, infrared spectroscopy, color, phenolic
compounds, rheological behavior, antioxidant and antimicrobial activity).
Results: The Surinam cherry and mango by-products in addition to the mombim, acerola and Surinam
cherry pulps were found to have the highest levels of quercetin. The Surinam cherry by-product was
selected to synthesize the cashew gum nanoparticles. Nanoparticles (Surinam cherry and standard quercetin)
have similar particle size, between 4.34 and 6.01nm. The Surinam cherry nanoparticle had higher
levels of phenolic compounds and similarly high antioxidant activity compared to control nanoparticles.
The samples showed a pseudoplastic behavior. The Surinam cherry nanoparticle synthesized with
cashew gum had lower minimum inhibitory concentration than pure fruit extract for Salmonella enterica.
Conclusion: The nanoparticles with Surinam cherry by-product extract can be included in food products
for higher level of bioactive compounds and as natural preservative.