Valorization of Avocado Seeds for Active Packaging: Comparative Analysis of Extracted Starch- and Seed Flour-Based Materials with Cinnamon Essential Oil

Abstract

This work aims to develop bio-based and biodegradable materials for active food packaging purposes by comparing the properties of avocado seed flour (ASF) and avocado extracted starch (AES). A 36.4% dry basis yield is obtained for the extracted AES from ASF. ASF presents a higher crystallinity, and SEM images show a mixture of starch granules and other materials, whereas AES presents lower ash, protein, and lipid content relative to ASF. To make a comparison between the two, ASF or AES are mixed with glycerol at different concentrations, then twin-screw extruded and injection-molded to develop thermoplastic starch-based materials. The morphological, mechanical, barrier, antioxidant, antimicrobial, and disintegrability properties are evaluated to compare their different compositions. ASF-based films exhibit better barrier properties and a 134% higher intrinsic antioxidant capacity. Conversely, the homogenous nature of AES-based materials results in better interactions with the plasticizer, allowing a wide range of mechanical properties. Moreover, cinnamon essential oil (CEO) was incorporated into the preferred compositions of both ASF and AES to improve antimicrobial properties. Adding a 5% concentration of CEO to samples was sufficient to completely inhibit the growth of P. expansum. These results support waste valorization for developing active packaging materials with high antioxidant and antimicrobial properties without competing for resources with the food industry.