Valorization of Vegetable Biomass as Moldable Biocomposites

The possibility of using macromolecules from vegetables, with minimal processing, as alternative feedstock to obtain materials capable of substituting plastics in packaging is a very compelling possibility. Succeeding in this strategy will help to mitigate the environmental issues associated with the use of non biodegradable single use plastics and plastic packaging.<br/>Furthermore, the possibility to use byproducts and waste from inedible parts of plants or discarded fruits and vegetables, will generate new value from resources that otherwise will be discarded, wasting also the energy and water used for their production. Using these waste and byproducts as a source of biomaterials will eliminate the controversy associated with the use of foodstuff (e.g. corn, sugars) to produce plastic alternatives such as starch-based plastics, PLA or PHAs.<br/>In this talk we will update on our work on the fabrication of biocomposites from vegetable pomace and waste using a mild hydrolysis in a process carried out only in water, at mild temperature and without the use of harsh chemicals. We successfully obtained films from biomass such as spinach stem, carrot pomace, orange peel, cocoa shells, cauliflower leaves, parsley stems. We were able to correlate the thermo-mechanical properties with the composition and morphology using a combination of techniques: solid state NMR, FTIR, SEM, confocal microscopy, dynamic mechanical thermal analysis and Time Domain NMR. We studied and verified the biodegradability of the final material and the preservation of plant-derived properties such as color and anti oxidant properties; finally we studied the migration of substances from the composite to food simulant. This knowledge allowed us to devise new fabrication techniques, such as hot embossing to obtain complex shapes and to study the materials as mulches for agricultural applications. The proposed production process was studied by Life Cycle Analysis, and compared to traditional plastics and bioplastics like HDPE, PET, PLA and starch. The vegetable biocomposites were more competitive than traditional plastics in terms of global warming potential and cumulative energy demand, and were more competitive than PLA in their water scarcity index.<br/>[1] Perotto G. et al, Green Chemistry, 2018<br/>[2] Perotto G. et al, Polymer, 2020<br/>[3] Simonutti R. et al, Sustainability & Green Polymer Chemistry Volume 2: Biocatalysis and Biobased Polymers 2021<br/>[4] Merino D. et al, Green Chemistry 2021