Title
Salting-in Effect on Muscle Protein Extracted from Giant Squid (Dosidicus gigas)
Author
Rui Zhang, Ru Zhou, Weichun Pan, Weiwei Lin, Xiuzhen Zhang, Mengya Li, Jianrong Li, Fuge Niu, Ang Li
Year
2016
Journal
Food Chemistry
Abstract
The salting-in effect on muscle protein is well-known in food science but hard to explain using conventional theories. Myofibrillar protein extracted from the giant squid (Dosidicus gigas) was selected as a model muscle protein to study this mechanism in KCl solutions. Changes in the secondary structures of myofibrillar protein molecules caused by concentrated salts, particularly in the paramyosin molecule conformation, have been reported. Zeta-potential determinations showed that these secondary structures have modified protein molecule surfaces. The zeta-potential of the myofibrillar protein molecules fell from −7.24 ± 0.82 to −9.99 ± 1.65 mV with increasing salt concentration from 0.1 to 0.5 M. The corresponding second virial coefficient increased from −85.43 ± 3.8 × 10−7 to −3.45 ± 1.3 × 10−7 mol mL g−2. The extended law of corresponding states suggests that reduced attractive interactions increase the protein solubility. Solubility measurements in alternating KCl concentrations showed that the conformational change was reversible.
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, Ligand binding, Biochemistry, Food science