Electrospun Wheat Starch Nanofibers for Encapsulation of Chlorogenic Acids from the By-product of Yerba Mate (Ilex paraguariensis)

Abstract The agricultural co-product generated from the pruning and harvesting of yerba mate ( Ilex paraguariensis ) is a rich source of chlorogenic acids, bioactive compounds sensitive to light and temperature that require protection to preserve their antioxidant activity. In this study, electrospinning was used to encapsulate chlorogenic acids from an optimized I. paraguariensis co-product extract into wheat starch nanofibers. The extract was incorporated at concentrations of 0%, 5%, 10%, and 15% (w/w), resulting in continuous, homogeneous nanofibers with smooth surfaces and average diameters ranging from 195 to 218 nm. Increasing extract concentration led to higher viscosity and electrical conductivity, contributing to the formation of thicker nanofibers. Encapsulation efficiency ranged from 90.8 to 63.7%, with the highest value observed for nanofibers whit 5% of extract. The nanofibers exhibited antioxidant activity against ABTS •⁺ and DPPH radicals, indicating partial preservation of bioactivity after encapsulation. Thermogravimetric analysis demonstrated increased thermal resistance of the encapsulated compounds compared to the free extract, confirming the protective effect of the starch matrix. The nanofibers showed a controlled release profile of chlorogenic acids, with slower release in hydrophilic media (10% ethanol) and faster release under lipophilic conditions (50% ethanol), highlighting their potential for different food applications. FTIR analysis confirmed interactions between extract compounds and starch, while contact angle measurements suggested increased hydrophilicity. Overall, wheat starch nanofibers proved to be an efficient and sustainable matrix for encapsulation and controlled delivery of bioactive compounds, contributing to the valorization of yerba mate co-products within a circular economy approach.