The ECHOS project successfully implemented all planned scientific and technical activities, resulting in validated processes and functional bio-based materials for sustainable food packaging applications. The work focused on the valorization of agro-industrial side streams through green extraction, biomimetic modification, and application-oriented material validation.
Green extraction methodologies were developed and optimized to recover functional phenolic–carbohydrate structures from a range of agro-industrial biomasses. Microwave-Assisted Extraction (MAE) was established as an effective acid-free hydrothermal process for citrus pectin recovery from orange, lemon, and lime peels, achieving competitive yields (up to ~20% relative to the initial biomass) while reducing chemical inputs and environmental impact. A broad biomass screening enabled the identification of coffee silverskin as a phenolic-rich source and citrus peels as a high-yield carbohydrate source. Comprehensive structural, physicochemical, antioxidant, and techno-functional characterization confirmed the suitability of the recovered pectins for further functionalization and material development. Enzymatic demethylation using pectin methyl esterase enabled controlled tailoring of pectin properties, expanding their functional versatility.
Building on these results, a biomimetic enzymatic strategy was developed to produce food-grade phenolic–carbohydrate conjugates. Phenolic extracts from coffee silverskin were successfully grafted onto citrus-derived pectins using oxidative enzymes, resulting in covalently modified polysaccharides with enhanced antioxidant activity, modified rheological behavior, and preserved thermal stability. Structural analyses confirmed effective phenolic incorporation, and an optimal extract-to-enzyme ratio was identified to balance grafting efficiency and polymer integrity. This approach demonstrated a reproducible and scalable route to active biopolymer ingredients derived entirely from food side streams.
The application potential of the developed materials was demonstrated through the preparation of edible films and coatings. Key functional properties relevant to food packaging, including water vapor barrier performance, surface characteristics, and solubility, were evaluated. The materials were applied as edible coatings on fresh fruit, and their ability to preserve quality during storage was assessed through weight loss, texture, and color stability measurements. In parallel, the feasibility of incorporating natural extracts into PLA-based films using extrusion and blown-film extrusion was explored, providing insight into alternative, industry-relevant processing routes for active packaging materials.
Overall, the ECHOS project delivered technically validated green extraction processes, biomimetic functional biopolymers, and proof-of-concept applications, fully achieving its scientific and technological objectives and providing a solid foundation for future upscaling and industrial implementation.
