Proteolytic degradation of tropical tilapia surimi

Proteolytic degradation of tropical tilapia surimi was biochemically and theologically characterized to identify a group of proteinase(s) responsible for its textural degradation. Proteolysis of tilapia surimi occurred as the temperature increased and attained the highest activity at 65 degrees C. Smaller proteins with molecular weight of 116-97 kDa were noted as a result of myosin heavy chain (MHC) degradation. MHC completely disappeared when incubated at 65 degrees C for 4 h. Proteolysis was significantly inhibited by soybean trypsin inhibitor (SB) and leupeptin (LE). Storage modulus (G') of surimi gels mixed with either SB or LE was higher than other inhibitors indicating that serine type proteinase(s) were involved in proteolysis of tropical tilapia surimi.