Co-authors​ :

 Luigi BOTTA (ITALY), Maria Chiara MISTRETTA , Giulia Lamattina (ITALY), Francesco GARGANO , Giorgia LIGUORI  

Currently, the issue of food waste is a prominent concern for businesses, governments, and consumers. Fruit processing results in the generation of various by-products, ranging from undesirables to fruit skins, seeds, and fleshy parts. These by-products constitute up to 30% of the initial mass of processed fruit. A way to valorize these by-products can be achieved by transforming fruit waste into reinforcement and integrating it into polymeric materials. The most natural and sustainable approach is to combine this kind of fillers with the use of biodegradable polymers as matrices. Among the different biopolymeric matrices suitable for this scope, polylactic acid (PLA) is one of the most interesting materials, as its chemical–physical properties allow the replacement of conventional oil-based polymers in several common applications. In this context, the utilization of cactus pear (Opuntia ficus-indica) by-products presents a promising avenue. The peel and glochids, which are typically discarded as waste, offer unique properties that could be effectively utilized as fillers in biocomposite materials. Cactus pear, a widely cultivated cactus, produces fruits containing both edible flesh and seeds. The peel, rich in fibers and other bioactive components, along with glochids, tiny spines found on the fruit's surface, can serve as valuable natural fillers for enhancing the mechanical and sustainable characteristics of polymeric materials. In this study, composites were prepared by incorporating cactus pear peel and glochids into a polylactic acid (PLA) matrix using the melt compounding technique. Composites were formulated at 10% and 20% by weight for both peel and glochids. The cactus pear peel was converted into micrometric particles suitable for incorporation into the biopolymeric matrix through two stages: drying and grinding. The drying procedure encompassed both conventional oven dehydration and freeze drying. Meanwhile, the glochids, being naturally micrometric and oblong in shape, were utilized as-is. The resulting materials were characterized morphologically through scanning electron microscopy (SEM), rheologically using frequency sweep tests with a rotational rheometer, mechanically through tensile and dynamic mechanical analysis (DMA), and calorimetrically using differential scanning calorimetry (DSC). This comprehensive characterization aims to provide insights into the structural, mechanical, and thermal properties of the developed biocomposites, contributing to the understanding of their potential applications in sustainable materials.