Obtaining a Protein Concentrate from Squid Mantle (Dosidicus gigas) by Direct Isoelectric Precipitation and Evaluation of its Gelling Capacity

Abstract

This study investigated protein recovery from squid mantle (Dosidicus gigas) using the following two methods: a conventional method (CM; water washing) and direct isoelectric precipitation (IP). The IP treatment offered a better yield. Protein fractionation showed a myofibrillar protein content of 64.83 ± 0.02 and 55.47 ± 0.05% for CM and IP, respectively. Differential scanning calorimetry showed differences in the myosin denaturation temperature with values of 37.27 ± 0.74 and 40.93 ± 0.41°C for the CM and IP treatments, respectively. Moreover, Surface hydrophobicity showed major hydrophobicity with the CM treatment. The total sulfhydryl content was higher in IP than in CM, but a decrease in sol-gel transition was more evident in CM than in IP. The hardness of the gel obtained from IP was higher than that of CM with values of 1695.66 ± 177.82_g-f and 668.33 ± 21.19_g-f, respectively. Direct isoelectric precipitation of protein from squid mantle generated a better yield and better functional protein compared to the conventional method.