Inhibition of Bigeye Snapper (Priacanthus Macracanthus) Proteinases by Trypsin Inhibitor from Yellowfin Tuna (Thunnus Albacores) Roe

The inhibitory effect of partially purified trypsin inhibitor from yellowfin tuna (Thunnus albacores) roe (TIYTR) on proteolysis of bigeye snapper (Priacanthus macracanthus) proteinases was investigated. TIYTR inhibited sarcoplasmic proteinases and autolysis of bigeye snapper mince and its washed mince at 60C in a concentration-dependent manner. Myosin heavy chain (MHC) in the mince and the washed mince of bigeye snapper was better retained when higher concentrations of TIYTR were used. The presence of NaCl (3.0% w/w) slightly enhanced the inhibitory activity of TIYTR (3.5-5.8%). Both TIYTR and beef plasma protein (at a level of incorporation of 3% w/w) showed higher inhibition of bigeye snapper proteinases than egg white (P<0.05). Based on inhibition studies, it is suggested that the trypsin inhibitor from the roe of yellowfin tuna can be a potential aid to suppress the gel weakening of bigeye snapper surimi, elicited by trypsin-like proteinases, during either setting or heating. Practical Applications: Yellowfin tuna (Thunnus albacores) roe is an abundant and underutilized resource that can be used as a source of trypsin inhibitors. Trypsin inhibitors from the roe of yellowfin tuna play a role in the inhibition of proteolysis in bigeye snapper (Priacanthus macracanthus) muscle. Thus, it can be a potential alternative for commercial trypsin inhibitor to inhibit proteolysis and enhance surimi gel strength.