A COMPARISON OF THE WATER HOLDING CAPACITY OF PRE- AND POST-RIGOR CHICKEN, TROUT AND LOBSTER MUSCLE IN THE PRESENCE OF POLYPHOSPHATES AND DIVALENT CATIONS

The water holding capacity (WHC) of rainbow trout (Salmo gairdneri) white muscle and lobster (Homarus americanus) tail muscle did not change from pre- to post-rigor. The trout muscle WHC values were similar to those of post-rigor chicken breast muscle and were not affected by the addition of sodium pyrophosphate (PP_i), Mg, Ca or combinations of these. In contrast, the WHC of lobster muscle was like the WHC of pre-rigor chicken breast muscle. The pre-rigor lobster muscle showed a large increase in WHC values with the addition of pyrophosphate (205% of control) but with the further addition of Mg to the sample the increase was depressed (166% of control). Ca addition to the pyrophosphate sample even more markedly depressed the WHC (90% of control). In both cases, Mg and Ca seemed to have approximately the same effect on WHC whether PP_i was present or not. Kena, on the other hand, increased the WHC of both pre- and post-rigor trout and lobster muscle. Ca seemed to negate the increasing effect Kena had on WHC. Kena plus Mg caused a large increase in the WHC of the prerigor lobster muscle; the WHC capacity with Kena alone was 123% of control while the WHC with Kena and Mg was 231% of control.