Effect of Protein Hydrolysate of Pearl Oyster Meat on the State of Water and Denaturation of Fish Myofibrils during Dehydration.

From the point of view of high utilization of pearl oyster meat, shellfish protein hydrolysates (SPH) were prepared from pearl oyster meat and three other kinds of shellfish meat by enzymic treatment using proteases. SPH of pearl oyster meat was added to myofibrils from lizard fish and the changes in the state of water in myofibrils associated with dehydration were analyzed on the basis of the sorption isotherm curve and isosteric sorption heat. Involvement of these changes in the denaturation of myofibrils was investigated with respect to ATPase activity as an indicator and the results were compared with those for SPH of three other kinds of shellfishes.The addition of SPH resulted in a decrease in water activity, an increase in the amount of monolayer or multilayer sorbed water and an increase in the isosteric sorption heat, indicating the changes in the state of water in myofibrils. Furthermore, it was found that SPH has supressive effects on the denaturation of myofibrils resulting from dehydration and there is a correlation between the repressive effects and the state of water.These results suggest that the supressive effects on the denaturation are likely to be attributed to the stabilization of the hydrated water surrounding myofibrils by the adittion of SPH.