THE EFFECT OF pH, POLYPHOSPHATES AND DIFFERENT SALTS ON WATER RETENTION PROPERTIES OF GROUND TROUT MUSCLE

The water binding potential (WBP) and expressible moisture (EM) curves of ground rainbow trout white muscle versus pH are different, particularly in the region from pH 5.0 to 7.0. The effect of different salts such as CaCl₂, Mg Cl₂, NaCl, Nal and Na₂SO₄ on WBP suggests that for the same salts, cations cause a smaller change than anions. On the other hand, the EM measurements suggest that cations have a greater effect on this measurement than anions. In the case of WBP, the effect of tripolyphosphate and pyrophosphate can be attributed solely to their effect on pH. These results indicate the differences between the two methods and suggest that they measure different components of the water retention properties of a complex system, and thus water holding capacity measurements must be interpreted with care.