AbstractBACKGROUND: Microbial transglutaminase (MTGase) can improve the mechanical and functional properties of restructured fish products without the need of thermal gelation. The present study seeks to determine whether, for different setting times, MTGase activity in restructured hake muscle made with pieces or with homogenised muscle can be affected by the quality of the protein in the raw materials.RESULTS: As regards mechanical properties, samples of both qualities subjected to the two different processes attained a suitable consistency after setting for 24 h at 5 °C. The quality of the protein in the sample is important when pieces are used for restructuring, but not when sample is homogenised. Also, there were strong correlations between residual MTGase activity up to 12 h and mechanical properties and electrophoretic band density. Water binding capacity (WBC) was not significantly altered by MTGase addition.CONCLUSION: The experimental combination of 10 g kg−1 of MTGase, 15 g kg−1 of sodium chloride and 7.5 g kg−1 of sodium caseinate was suitable for the production of minimally processed raw restructured fish products made with two different qualities of fish protein and two different restructuring processes. In the restructured products made with pieces, the protein quality significantly affected final properties, but in finely homogenised product the protein quality was less important. Copyright © 2009 Society of Chemical Industry