Zein electrospun fibers with red onion extract (Allium cepa L.): Bioactive compounds, thermal stability, hydrophilicity, and antioxidant activity

Abstract

Onions are rich in bioactive and volatile compounds with antioxidant activity. When concentrated in plant extracts and applied directly into food matrices or packaging, they are sensitive to external factors and may have undesirable sensory attributes, such as odors. Therefore, this study sought to encapsulate red onion extract (ROE) in different concentrations (10, 20, 30, and 40%, v/v) into zein fibers by electrospinning. The major volatile compound in ROE was 3(2H)-furanone, 2-hexyl-5-methyl. Adding ROE into the polymeric solutions increased their electrical conductivity and decreased the apparent viscosity, thus decreasing the average diameter of the fibers. The loading capacity of ROE on fibers ranged from 77.3 to 91.5%. The fibers’ random and continuous morphology showed beads at the highest ROE concentration (40%). Fibers membranes showed lower values ​​for contact angles as ROE was added. The antioxidant activity of the fibers ranged from 32.5 to 57.3%.