Electrospun Starch Fibers Loaded with Pinhão (Araucaria angustifolia) Coat Extract Rich in Phenolic Compounds

Abstract

Pinhao coat extract is rich in phenolic compounds. Thus, the present study aimed to encapsulate pinhao (Araucaria angustifolia) coat extract (PCE) in electrospun starch fibers, and evaluate its antioxidant activity and in vitro release. The PCE’ total and individual phenolic compounds were evaluated. Fiber-forming polymer solutions were prepared within 50% of soluble potato starch in 75% of formic acid containing PCE in various concentrations [0%, 0.5%, 1.0% or 1.5% (w/v)] and measured by its rheological parameters and electrical conductivity. The fibers were electrospun and evaluated by efficiency of encapsulation, morphology, size distribution, thermal stability, infrared spectrum, antioxidant activity and in vitro release. The PCE presented high amount of total phenolic compounds (225.32 ± 0.89 μg·g−1) and high concentrations of catechin/epicatechin dimer and catechin. The electrospun starch fibers had encapsulation efficiency values of 62–100% and improved fiber morphology. Encapsulated PCE presented higher thermal stability than its free form and FT-IR spectra showed interactions between fibers constituents. Starch fibers loaded with different PCE concentrations showed antioxidant activity of 28% inhibition, with no statistical difference between the concentrations (p ˃ 0.05). The fibers showed rapid and in low quantities in vitro release, with fibers loaded with 0.5% PCE presenting higher encapsulation efficiency and lower % release. Throughout this study outcome, we can suggest that this biodegradable nanomaterial is applicable as an antioxidant agent in the food industry.