Sustainable Bioactive Films From Avocado Seed Starch: Biodegradable Extruded Materials Reinforced With Starch Nanocrystals for Active Packaging

ABSTRACT Biodegradable films were developed from starch extracted from avocado seeds (ASS) and reinforced with starch nanocrystals (SNCs) to investigate the effect of nanofiller incorporation on thermal, mechanical, barrier, antioxidant, and antimicrobial properties. Thermogravimetric analysis showed that the incorporation of SNCs improved thermal stability, with higher onset degradation temperatures compared to the neat ASS film. Furthermore, water vapor permeability decreased significantly with increasing SNC content (from 1.64 × 10⁻⁹ to 0.92 × 10⁻⁹ g·s⁻¹·m⁻¹·Pa⁻¹), indicating enhanced barrier performance attributed to the tortuous path effect introduced by the nanocrystals. Interestingly, all films exhibited remarkable antioxidant and antimicrobial activity ( Staphylococcus aureus ) due to the intrinsic bioactive compounds present in ASS. The incorporation of SNCs further enhanced antioxidant activity, from 45 to 63 mmol TEAC/g at 3% SNC loading. All formulations exhibited comparable disintegration under composting conditions, achieving near complete degradation within 28 days. These findings highlight that ASS‐based films reinforced with SNCs combine improved functional properties with inherent bioactivity, positioning them as promising candidates for active and sustainable food packaging applications.