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

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.