Synthesis and Characterization of Quercetin@Ca3(PO4)2 Hybrid Nanofibers with Antibiofilm Properties and Antioxidant Activity for the Deep-frying Procedure of Sunflower Oil

Quercetin, the well-known abundant natural flavonoid, displays a wide range of biological and medicinal properties with antioxidant, anticancer, antimicrobial, and antibiofilm activities. However, poor aqueous solubility and low stability limit its potential prophylactic or therapeutic uses. In the present study, a novel type of quercetin-loaded Ca₃(PO₄)₂·hybrid nanofibers (HNFs) was fabricated to overcome the mentioned restrictions. The nanostructures were instantly prepared by the incubation of a mixture containing quercetin (0.1 mg mL^–1), calcium chloride (40 mM), and phosphate buffer (100 mM, pH 7.5) at 25 °C. The high-performance liquid chromatography (HPLC) results indicated a successful entrapment of quercetin into the prepared HNFs (98%). Compared to the free quercetin, the encapsulation showed 13- and fourfold increases in the prepared HNFs’ stability at 60 °C and pH 2 and 4, respectively. After a 240-min exposure to the UV light, 90% of the flavonoid loaded on the fabricated HNFs remained intact in the aqueous solution. Quercetin@Ca₃(PO₄)₂·HNFs protected the fatty acids composition of sunflower oil from lipid peroxidation up to 55% after 70 frying cycles. The prepared HNFs (2.5 mg mL^–1) disassembled biofilms formed by Staphylococcus aureus (82.5%), Bacillus subtilis (80%), Escherichia coli (66%), and Pseudomonas aeruginosa (30%). As a result, quercetin@Ca₃(PO₄)₂·HNFs can be purposed as an antibiofilm and antioxidant to preserve sunflower oil. These promising results confirm that quercetin@Ca₃(PO₄)₂·HNFs provide a good potential for eventual application in the food industry as an antibiofilm or antioxidant agent.