Autolysis and Protease Inhibition Effects on Dynamic Viscoelastic Properties during Thermal Gelation of Squid Muscle

ABSTRACT: Viscoelastic changes during thermal gelation of squid ( Loligo vulgaris ) muscle with protease inhibitors were studied, in order to evaluate the contribution of different proteinases to gel degradation. Calcium chloride was also tested as enzyme activator. A minimum in elastic modulus without inhibitors was achieved at 38 to 40°C. Although denaturation temperature was around 55°C, pronounced melting of connective tissue started at 40°C. Proteolysis occurred between 25 and 75°C, with maximum at 40 to 45°C. Addition of PMSF led to highest values of G'. The strong inhibition of autolytic activity by PMSF confirmed the predominance of serine proteases. Addition of CaCl₂ favored thermal protein aggregation from 40°C upwards.