Production and Functional Evaluation of a Protein Concentrate from Giant Squid (Dosidicus gigas) Fins Obtained by Alkaline Dissolution

Two protein concentrates from jumbo squid fins (Dosidicus gigas) were elaborated. One of them was obtained via alkaline dissolution and subsequent isoelectric precipitation (alkaline protein concentrate [APC]) and the other was obtained via the traditional method (neutral protein concentrate [NCP]). The electrophoretic profile of the APC showed that the myosin heavy chain band disappeared, mainly due to the denaturation induced by alkaline solubilization or activation of alkaline protease. Concerning the quality of the gels, the folding test showed that gels obtained using APC were better than those obtained using NPC, but a texture profile analysis detected fracture in the APC gels. Regarding the interfacial properties, low emulsifying capacity was observed for both protein concentrates, and the APC was better than the NPC. Additionally, the foaming properties were excellent for both concentrates and were significantly better for APC. Therefore, the alkaline solubilization process for fin squid was suitable for the production of functional protein concentrates. Practical Applications: One of the challenges of the fishing industry is to achieve an integral use of fishing resources. Jumbo squid is an abundant resource in Northwest Mexico and its by-products generate a great of waste, which are an environmental problem. Viscera, heads and fins are the main waste of jumbo squid. Fins are about 10% of the total animal; therefore, their exploitation is a good option for this industry. Hence, this study compares and evaluates the functional properties of the protein concentrates obtained from squid fins via alkaline dissolution and subsequent isoelectric precipitation and the conventional methodology (water washing muscle) to determine the most feasible method of obtaining protein concentrates from squid fins.