Testing added-value fish oils from marine by product for cosmetic and nutraceutical application

This PhD thesis focuses on the study of fish oils reach in polyunsaturated fatty acids (PUFAs) derived from by-streams of the fishing industry, with the aim of evaluating their potential applications in the cosmetic and nutraceutical sectors. PUFAs are essential nutrients that play a critical role in maintaining human health. Humans cannot synthesize PUFAs, so they must be obtained from the diet, through plant-based foods like nuts and vegetable oils, and animal-based foods, primarily marine sources such as fish. Building on this need for external PUFA sources, this thesis highlights the advantages of marine PUFAs as a safe, environmentally friendly and affordable resource, in line with the principles of the Blue Economy. The Blue Economy promotes the sustainable use of marine resources through practices such as responsible fishing, ecotourism and innovative research, contributing to both economic development and conservation of the marine ecosystem to ensure long-term benefits for coastal communities and ocean health. To this aim, a circular economy approach, focusing on efficient resource management using fish by-products, especially small oily fish such as sardine (Sardina pilchardus) and mackerel (Scomber scombrus), to extract bioactive PUFAs beneficial to human health. To investigate the potential of these marine-derived PUFAs, different types of analyses were performed in the frame of the H2020 EcoeFISHent project (ID: 101036428). To this end, we gained experience by evaluating benchmark fish oils with the aim of establishing a tiered approach that allows for increasing the complexity of experiments, progressing from lower tiers to higher ones. Effective screening methods, including UV spectroscopy, antioxidant assays and UV protection assays, were employed as a proxy of sample bioactivity. Then, for cosmetic application we performed tests on human keratinocyte cells on both active principle and formulated products and the complexity was further increased by testing the fish oils on 3D reconstructed human skin models. Research conducted abroad at ANFACO-CECOPESCA under the supervision of Dr. Mercedes focused on the in vitro digestion of commercial PUFA-rich fish oil, demonstrating its potential also in nutraceutical applications with tests on human liver cells and 3D reconstructed human intestine models. The beneficial effects of digested PUFAs have been demonstrated, evaluating both the effects on cell and tissue viability and the effects on lipid metabolism. In conclusion, this doctoral research has demonstrated the potential of fish by-products as a source of valuable molecules with different applications, highlighting the beneficial effects of fish oils on human health. This approach promotes the responsible and sustainable use of fish resources, while promoting scientific and industrial research in the cosmetic and nutraceutical sectors.