Red onion skin extract rich in flavonoids encapsulated in ultrafine fibers of sweet potato starch by electrospinning

Elder PAchedo da cruz, Estefani Tavares Jansen, Laura Martins Fonseca, Helen Cristina dos Santos Hackbart, Tatiane jéssica Siebeneichler, Juliani buchveitz pires, Eliezer Avila Gandra, Cesar Valmor Rombaldi, elessandra da rosa zavareze, Alvaro Renato Guerra Dias

Abstract

Electrospinning encapsulation is a highly viable method to protect bioactive compounds and prevent their degradation. Hence, this study produced ultrafine fibers based on yellow and white sweet potato starches and a red onion skin extract (ROSE; 0, 3, 6, and 9 %, w/w) using electrospinning. The fibers were evaluated for morphology, thermogravimetric properties, antioxidant, in vitro release simulation, thermal resistance (100 and 180 °C), and wettability. The fibers with ROSE presented 251–611 nm diameters, 67–78 % loading capacity, and 51.6–95.4 and 13.4–99.4 % thermal resistance (100 and 180 °C, respectively); apigenin presented the highest thermal protection. The phenolic compounds showed low release using 10 % ethanol and greater release with 50 % ethanol. The fibers with 9 % ROSE showed 2,2′-azino-bis(3-ethylbenzothiazoline) 6-sulfonic acid radical inhibition above 92 %. The ultrafine fibers and the unencapsulated ROSE showed inhibitory action against Escherichia coli and Staphylococcus aureus; only unencapsulated ROSE showed bactericidal activity.

https://doi.org/10.1016/j.foodchem.2022.134954