Determinación de la presencia y el origen del fenómeno modori en surimi de cinco especies de pescado del Golfo de México / Determination of the modori phenomenon and its origin in surimi of five fish species from the Gulf of Mexico

Abstract

Modori is a phenomenon which occurs in fish gels only when they are incubated at 50-70 °C, and which induces a decrease in their mechanical properties. Modori has been associated with endogenous proteases, varying among fish species. Surimis were obtained from Atlantic croaker ( Micropogon undulatus) , barred grunt ( Conodon nobilis) , sole ( Cyclopsetta chittendeni) , northern kingfish ( Menticirrhus saxatilis) and striped searobin ( Prionotus evolans). The effect of gel incubation time on shear stress and shear strain at failure, soluble peptides and electrophoretic pattern was studied. Incubation times at 60 °C, of 0, 20 or 40 min were assayed. The modori phenomenon induced a significant decrease (25-50%) in the mechanical properties of the five species studied. This phenomenon was associated with the presence of active proteases at 60 °C, determined as an increase in concentration of soluble pep tides depending on the time of incubation. Proteases were partially characterized employing serine- and cysteine-protease inhibitors. The studies with SDS-PAGE showed that myosin is the main substrate of the proteases. Actin was not hydrolyzed. The employment of specific inhibitors showed that both serine- and cysteine-proteases were associated with the modori phenomenon in the species studied.