Effect of high-pressure and/or microbial transglutaminase on physicochemical, rheological and microstructural properties of flying fish surimi

Microbial transglutaminase (MTGase), pressure treatment (HP) and a combination of both treatments were evaluated in the formation of flying fish surimi (FFS) to improve its functional properties for use in the fabrication of restructured seafood products. Four samples were made: C-0 (Control), made by FFS setting (40 degrees C/30 mm) and heating (90 degrees C/30 mm), C-08 (sample C-0 with 0.8% MTGase), HP-0 (sample C-0 subjected to 80 MPa) and HP-08 (samples HP-0 with 0.8% MTGase). Physicochemical, rheological and structural properties were measured. Sample C-08 was the most rigid gel, with the highest level of structural organization due to the greater proportion of covalent bonds. Conversely, HP produced more elastic and time-stable networks as a result of the recombination of weak bonds due to the compression-expansion effect. No synergic effect was observed (HP-08), since the pressure-induced change in protein conformation led to a reduction of MTGase activity. These findings were consistent with the results of scanning electron microscopy. Industrial relevance: The industrial relevance of the present work lies in the possibility of using low quality flying fish surimi (FFS) to make value-added seafood products. This would be achieved by using different treatments commonly employed in the food industry, such as microbial transglutaminase incorporation during the final product fabrication process and/or the application of low high pressure treatments (80 MPa) to achieve adequate mechanical properties in the final product. (C) 2013 Elsevier Ltd. All rights reserved.