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 APPLICATIONSOne 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.

The effect of bovine plasma protein (BPP) on the inhibition of autolytic activity and its effect on the gelling properties of a protein concentrate (PC) obtained from jumbo squid (Dosidicus gigas) mantle were investigated. Sols and gels were prepared from the PC by adding different amounts of BPP (0, 1, and 2%). Dynamic oscillatory measurements indicated that systems with 1% BPP had a higher elastic modulus (G′), in which hydrophobic interactions were favored. Concerning the technological and textural quality of the gels, BPP caused a greater water holding capacity (WHC), force, cohesiveness, and elasticity, probably due to improvement of the electrostatic and hydrophobic interactions during gel formation. Scanning electron microscopy (SEM) allowed visualization of the formation of more rigid and ordered gels with less porosity when BPP was added. Therefore, the addition of BPP improved the gelling capacity of proteins extracted from giant squid.