Effects of pH and Sodium Chloride on the Gelling Properties of a Protein Concentrate Obtained from Jumbo Squid Mantle (Dosidicus Gigas)

Jumbo squid (Dosidicus gigas) is an underutilized fishery resource in the Gulf of California. Jumbo squid muscle could potentially be utilized to manufacture protein concentrates to be used as a base for surimi or as a food ingredient. However, the main problem is the low gelling ability of these protein concentrates compared those of with fish species. Consequently, the present study evaluated the effects of pH and the NaCl concentration on the gelling properties of protein concentrates from squid mantle. According to texture profile analysis, improved gelling properties were obtained at pH 6.0 and 1% of NaCl. During the sol-gel transition, decreased surface hydrophobicity that corresponded to an increased intensity of α-helix structures was detected. Moreover, the total sulfhydryl content decreased during gel formation. Viscoelasticity and water holding capacity analyses showed the formation of a more structured gel at pH 7.0. The higher enthalpy and denaturation temperature detected by differential scanning calorimetry at pH 7.0 and 1% NaCl showed that both variables (pH and NaCl concentration) affected the protein structure and conformation. The results demonstrated that varying pHs and NaCl concentrations improved the gelling properties of protein concentrates from squid.