Maulvault, Ana Luísa Marques Paixão de CarvalhoRepolho, Tiago Filipe Baptista da Rosa, 1974-Bolotas, Daniel Marmelo2025-01-0820242024http://hdl.handle.net/10400.5/96948Tese de mestrado, Ciências do Mar, 2024, Universidade de Lisboa, Faculdade de CiênciasSince the production of the first plastic in 1907, bakelite, the pervasive issue of plastic pollution has become a significant environmental and health concern, prompting the industry to shift its attention towards more sustainable alternative materials. Despite the growing interest in bioplastics (e.g. polylactic acid, PLA), the toxicological attributes of these polymers to humans remains unclear. The present study aims to assess, in a comparative way, the effects of conventional polyethylene terephthalate (PET) and PLA microplastics (500 – 1000 µm) unintentional ingestion through seafood, using a standardized in vitro bioaccessibility model. In addition, potential alterations in plastics‘ morphology associated with mechanical, chemical and enzymatic actions during digestion were also investigated by conducting a thorough inspection of the particles (before and after the in vitro digestion). To this purpose, Binocular Stereomicroscopy, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used. The matrix effect was also explored by simulating the in vitro digestion of three distinct seafood products: gilthead seabream (Sparus aurata) and Atlantic salmon (Salmo salar) fillets, and hard clam (Mercenaria mercenaria) edible portion. Results indicated differential degradation patterns between PET and PLA microplastics upon the human digestive process, with PLA showing signs of higher degradation (increased number and enlargement of pores on the surface). Protein digestibility in seabream and salmon fillets was consistently around 86% for both, whereas in clam the values were around 73%, regardless of microplastics presence, confirming that the seafood digestion process was not interfered by the co-ingestion of PET and PLA particles. In addition, the number of particles (10 versus 20) did not significantly affect the digestive process either. All in all, this work contribute to a better understanding of microplastics impacts on human health, emphasizing the need for improved management strategies for plastic waste and the development of safer, biodegradable alternatives.engsegurança no pescadopoluição de plásticobioacessibilidade in vitroácido polilácticopolietileno tereftalatoTeses de mestrado - 2024master thesis203880544