Eco-friendly biofilms from chemically modified Indian teff (Eragrostis tef) starch for quality maintenance and shelf-life improvement of green grapes

Abstract

This study explores the development of sustainable teff starch-based biodegradable films enhanced through oxidation and cross-linking to improve their suitability for food packaging applications. The modified films were evaluated for improved strength, barrier performance, thermal stability, and effectiveness in preserving fresh green grapes. The native film (NF) showed a tensile strength of 3.07 MPa and 38.21% elongation at break. Oxidized films exhibited higher tensile strength, while cross-linked films achieved strengths of 6.62 and 6.71 MPa, maintaining comparable elongation, indicating improved mechanical properties and rigidity. The NF exhibited a water vapor permeability (WVP) of 4.09 × 10⁻⁸ g m⁻² s⁻¹ Pa⁻¹. In contrast, oxidized films (2.09 and 2.5 × 10⁻⁸ g m⁻² s⁻¹ Pa⁻¹) and cross-linked films (3.00 and 3.98 × 10⁻⁸ g m⁻² s⁻¹ Pa⁻¹) showed substantially lower WVP values, reflecting improved moisture barrier properties. The oxidized films and cross-linked films showed increased thermal stability, with decomposition temperatures exceeding 260 °C, highlighting their suitability for durability applications. Oxidized films and cross-linked films demonstrated superior UV protection by significantly increasing UV absorption and reducing harmful transmission, thereby enhancing the preservation of packaged product. Application trials on green grapes revealed that modified films significantly reduced weight loss, preserved firmness, and slowed acidity reduction during storage, extending fruit shelf life. Overall, these findings establish chemically modified teff starch films as promising next-generation biodegradable packaging materials with reinforced strength, stability, and preservation performance—offering a sustainable and eco-friendly alternative to petroleum-based plastics for fresh produce packaging.