Starch nanofibers as vehicles for folic acid supplementation: thermal treatment, UVA irradiation, and in vitro simulation of digestion

Background: The supplementation of folic acid in food is essential in the human diet. The present study aimed to encapsulate folic acid at different concentrations (5, 10, and 15% w/w on a dry basis) in potato starch nanofibers produced through electrospinning. The starch/folic acid nanofibers were evaluated through morphology, FTIR spectra, thermal properties, encapsulation efficiency (EE), and in vitro simulation of the human digestion. The nanofibers were also evaluated based on the folic acid content after thermal treatment (100 and 180 °C) and UVA irradiation (1 and 24 h).

Results: The folic acid incorporation influenced the morphology of the nanofibers to display a homogeneous and beadless morphology for nanofibers containing 15% of folic acid compared with the other nanofibers (0, 5, and 10% of folic acid). The mean diameter varied from 75 to 81 nm. Folic acid characteristic bands and peaks were not found in the FTIR spectra and nanofibers thermograms, respectively. The EE was 73, 87, and 95% for nanofibers with 5, 10, and 15% of folic acid, respectively.

Conclusion: The starch nanofibers protected folic acid from high temperature and UVA irradiation and during in vitro digestion, showing a release of the vitamin at the end of the simulation (intestinal conditions). The supplementation of folic acid in foods can be effectively achieved by its encapsulation into starch nanofibers, to ensure its protection and controlled release. This article is protected by copyright. All rights reserved.

Keywords: Electrospinning; Encapsulation; Starch/folic acid nanofibers; in vitro digestion.