Evaluation of alternative materials to conventional multilayer packaging for a sustainable transition in the food industry

Since the last century, plastics have increasingly gained a significant share of the packaging sector due to their versatility, affordability, and durability. In recent decades, environmental concerns have arisen regarding plastic pollution, which is an inevitable consequence of the use of fossil-based resources, whose extraction contributes to CO₂ emissions, as well as of polymer degradation into microplastics, affecting both terrestrial and marine ecosystems. In the food packaging sector, conventional plastic materials are necessary for single-serve sachet formats, as they provide suitable mechanical and thermal properties and, above all, high barrier performance, which is essential to protect and preserve products. Growing global awareness of plastic waste, together with increasing regulatory pressure, is driving a shift toward more sustainable solutions for these formats while maintaining the functional requirements necessary for both scientific research and industrial development. In order to support the ongoing transition toward circularity, the aim of this thesis is to evaluate sustainable alternatives to conventional single-use flexible packaging in the food industry. The research was structured into two main workstreams: (a) recyclable solutions, focusing on monomaterial alternatives, and (b) compostable solutions. Of the results obtained, it is possible to see how monomaterial can represent a valid sustainable solution compared to multilayer material, managing to satisfy performative packaging requirements for products such as condiments and recycling requirements. As for compostable solutions, however, these have limitations in mechanical performance and barrier properties for this type of product and for the long shelf life required by the industry. Several data and results were then collected, providing a broad view of possible options and also a solid basis for future research and implementation of more sustainable packaging solutions.