Washing effect of minced fish muscle in water on degradation of polyphosphates during manufacturing process of surimi-based products

The washing effect of minced fish muscle on the degradation of polyphosphates (PP) in the salted meat paste (SMP) during the setting process was studied. Surimi MW0-MW4 were made from minced Walleye pollack muscle by washing 0-4 times with a buffer solution (pH 7.5). Aliquots of the SMP MWO-MW4, which were mixtures of surimi MWO-MW4, NaCl, and tripolyphosphate (P3), were incubated at 20-degrees-C. Degradations of P3 and pyrophosphate (P2) in the SMP during the setting process were determined. In the SMP MWO, P3 was rapidly degraded to P2 and P2 thus formed was also rapidly degraded to orthophosphate. As the number of washing times increased, the degradation rates of both P3 and P2 slowed down and P2 became hard to be degraded in SMP MW2-MW4. In order to determine the mechanism of this phenomenon, the amounts of tripolyphosphatase (P3ase), pyrophosphatase (P2ase) and magnesium (Mg) as an enzyme activator in surimi MWO-MW4 were measured. Along with the washings, P2ase and Mg were washed out from minced muscle, but P3ase was not. The decrease in Mg concentration suppressed P3ase activity in the SMP. Thus, repeated washing of minced muscle seemed to have an effect to degrade P3 and P2 in the SMP during the setting process.