Starch-based Al2O3 nanocomposite films for enhanced shelf-life and sustainable food packaging

Abstract

• Incorporation of 0.4 wt% Al 2 O 3 nanoparticles into starch-glycerol films improved tensile strength. • Packaging bananas with the optimized nanocomposite films prolonged shelf life by up to 10 days. • Films exhibited ∼17% weight loss in soil over 4 weeks. Petroleum-derived conventional packaging raises environmental concerns that have prompted researchers to seek alternatives for decades. The primary solution to replace petroleum-based packaging lies in biodegradable packaging that can naturally decompose in soil, water, and/or the environment. This research primarily aims to enhance the shelf life, biodegradability, and mechanical flexibility of corn starch films by incorporating glycerol as a plasticiser and alumina (Al 2 O 3 ) reinforced nanoparticles. Analytical characterisations indicate that successfully introducing glycerol and Al 2 O 3 nanoparticles into the crosslink of corn starch significantly improved optical transmission and reduced the intensity of the hydroxyl group. This modified packaging has enhanced the mechanical and physical properties (tensile strength, water vapour transmission rate (WVTR), contact angle (CA), and water solubility (WS)) of the starch-alumina-glycerol film. The current research presents the incorporation of Al₂O₃ nanoparticles in starch-based matrix significantly enhances flexibility, barrier properties and transparency, resulting in biodegradable packaging films that perform better for extending food shelf life. Furthermore, the biodegradation of this novel packaging and the shelf life of bananas were qualitatively improved, leading to promising food preservation and flexible packaging applications.