Degradation of polyphosphates during manufacturing process of surimi-based products.

A method of high-performance liquid chromatography (HPLC) using post column reaction system has been established by us for the determination of polyphosphates (PP) in foods and PP contents in commercially available surimi-based products have also been examined. In the present investigation, behavior of PP during the manufacturing process of surimi-based products was studied. Surimi was made from Alaska pollack muscle washed twice with a buffer solution (pH 7.5). Aliquots of salted meat paste, which was a mixture of surimi, NaCl and tripolyphosphate (P3), were incubated under various conditions. After incubation, aliquots were homogenized with ice-cold 6% trichloroacetic acid and centrifuged. The super-natants obtained were applied to HPLC for the determination of PP. It was found that P3 was enzymatically degraded to pyrophosphate (P2) and orthophosphate (P1) in the salted meat paste during grinding and setting processes, but P2 was seldom degraded to P1. Optimal temperature, NaCl concentration, and pH of tripolyphosphatase (P3ase) activity in the salted meat paste were around 27-degrees-C, 6.0%, and 6.0, respectively. P3ase was rapidly heat-inactivated at temperatures above 35-degrees-C. Although thermal degradation of P3 occurred during heating process, the degree of degradation was much smaller than that by P3ase during grinding and setting processes.