Functional evaluation of a protein concentrate from jumbo squid

Viscera of marine resources represent roughly 10-20% of the total specimen weight and should be studied for utilization in the food industry. In this study, a protein concentrate (PC) was obtained from the viscera of jumbo squids (Dosidicus gigas). Protein fractionation of the viscera material yielded 45.08 ±2.09% sarcoplasmic protein, 38.91 ±0.07% myofibrillar protein and 10.27 ±0.18% alkali-soluble proteins, while the PC showed values of 29.53 ±0.17, 51.20 ±0.75% and 15.92 [+ or -]0.15%, respectively. The electrophoretic pattern showed the presence of high molecular weight aggregates and sarcoplasmic proteins and/or hydrolyzed proteins of different molecular weights in both systems. It was possible to obtain gels of protein from viscera, but it was not possible to do so from PC. Viscera and PC were not significantly different (p>0.05) in emulsification capacity, but the former was more stable; it also showed better foaming capacity than PC, but no difference (p>0.05) was detected in the foam stability. The results indicate that the proteins present in the viscera of jumbo squid have low-quality gelling properties, but proteins of this by-product showed good emulsification and foam properties, which could be exploited in the production of food or food ingredients intended for human consumption.