AVOCADO SEED-DERIVED BIOPLASTICS AS ACTIVE COATINGS FOR CARDBOARD

Cardboard is widely used in packaging due to its biodegradability, recyclability, and compatibility with circular economy systems. However, its porous and hydrophilic structure limits barrier performance, especially against moisture and oxygen, restricting its use in food packaging without additional layers. Conventional coatings often use synthetic polymers or metals, which compromise recyclability and biodegradability. Environmental concerns over fossil-based plastics have increased demand for sustainable alternatives, such as bioplastics from industrial agri-food waste, promoting by-product valorization and supporting the circular economy. These wastes, rich in bioactive compounds and nutrients, can yield materials with valuable properties, such as moisture-wicking and antioxidant activity. As part of the BIOCOATING project, this study developed avocado seed-derived bioplastics as active coatings for cardboard to enhance functionality while maintaining circularity. Avocado seeds, an underused agri-food residue, were utilized as a source of bioactive compounds and starch-rich fractions suitable for thermoplastic processing. The research followed five stages: (i) preparation and characterization of avocado seed; (ii) production of thermobioplastic granulates; (iii) development and analysis of bioplastic films; (iv) hot stamping of films onto cardboard; and (v) evaluation of coated samples. The films showed a brown color, flexibility, and demonstrated moisture-wicking and antioxidant properties. Once applied via hot stamping, the coatings adhered well and formed a continuous layer. These findings show that avocado seed-derived bioplastics can give cardboard packaging active and protective functions, supporting circular design by reducing dependence on fossil-based plastics and enabling waste valorization.