From tuna viscera to added-value products: A circular approach for fish-waste recovery by green enzymatic hydrolysis

Tuna represents one of the most consumed foods in many parts of the world. It is estimated that about 70 % of the tuna's weight is discarded in the production of canned fillets. This work is focused on the optimization of production of an oil rich in omega-3 from the tuna viscera, provided by a canned tuna production company, using the Alcalase enzyme. Combined use of Design of experiments (DoE), life cycle analysis (LCA), and principal component analysis (PCA) on the collected analytical data made it possible to define the best combination of the values of pH, enzyme/substrate (E/S) ratio, and reaction time, respectively (pH = 8.5), E/S (1 %), and time (120 min), and to better understand the environmental bottleneck of the process. The outcomes of the study demonstrated that the duration of the hydrolysis and the associated electricity consumption is the factor that affects the most the environmental sustainability of the process.