Electrospinning of gelatin fine fibers loaded with hop waste extract: Development, characterization, and application as antioxidant chitosan bilayer films

Abstract

The present work demonstrated the potential of recovering bioactive compounds from hop waste extract using green solvents and incorporating them into fine gelatin fibers. The fine fibers were deposited on chitosan films, producing a bilayer film. Afterward, the bilayer film was characterized and applied as an antioxidant. Hop waste extract was characterized by lipid content, total phenolic content, and total flavonoid content. The extract was a good source of flavonoids (>8.4 mg QE g⁻¹). Electrospinning solutions were characterized by viscosity and electrical conductivity. Fine gelatin fibers loaded with hop waste extract as a source of an antioxidant agent were developed using the electrospinning method. The operational conditions were conducted under 22.4 kV, needle tip-to-collector distance of 13.75 cm, and flow rate of 1.2 mL h⁻¹). Electrospinning of pure gelatin and gelatin incorporated with hop waste extract solutions was formed on the chitosan films. The fibers obtained by the electrospinning process were evaluated by the properties of thickness, color, morphology, thermal stability, functional groups, and hop extract incorporation efficiency. Bilayer films were characterized by thickness, tensile strength, elongation-at-break, water vapor permeability, and morphology. The antioxidant activity against the DPPH radical of fibers loaded with bioactive compounds improved by 71.1 % compared to the pure gelatin fiber. Selected electrospinning solutions were collected on chitosan films to produce antioxidant bilayer films. Compared to the pure chitosan film, the bilayer film elongation increased by 65 %, and antioxidant activity increased by 85 %.