TG in SURIMI
Before fish protein gelation, adding a gel strength enhancer is an effective way to improve the gel strength. Ca2+ plays an important role in the gel strength of fish protein. In the process of fish protein gelation, calcium ions activate the transglutaminase (TGase) in fish meat, and then catalyze the γ-carboxamide group in glutamic acid residues and other Amino acid residues undergo cross-linking, forming a stronger network structure through covalent bonds.
For fish species with less transglutaminase (TGase) content in fish meat, such as freshwater fish such as carp, microbial BTGase can be added to improve the gel forming ability. The mechanism by which TGase promotes the cross-linking and recombination of fish protein is: TGase catalyzes the cross-linking of glutamic acid Gln residue γ-carboxamide group with lysine Lys residue ε-amino group, producing ε within or between molecules -(γ-Glu) Lys bridging and bonding, forming a cross-bonded protein structure, and the gel strength of the gel increases with the increase of TGase content.
Add starch etc. to fish meat to strengthen the gel. The function mechanism of starch is that during heating and gelatinization, free water is absorbed by the added starch to become passivated water. Because the mechanical strength of the swollen gelatinized particles is greater than that of fish meat, it plays a role in strengthening fish meat elasticity and improves the gel strength. Vegetable protein, gelatin, egg white and other substances are also elastic enhancers for surimi products.