The effect of washing water parameters (pH, hardness and sodium pyrophosphate content) on the water-holding capacity and gelation characteristics of sardine (Sardina pilchardus) mince

 In order to determine the effect of washing water parameters [pH, hardness and tetrasodium pyrophosphate (TSPP) content] on the water-holding capacity (WHC) and gelation properties of sardine (Sardina pilchardus) mince, two experiments designed by response surface methodology were carried out. The WHC of the mince was maximum when washed in the pH range of 6.5–7.0, with TSPP>1.7 g ⋅ l-1, and CaCO3 between 30 and 60 mg ⋅ l-1. With the exception of breaking deformation and the folding test, where the highest values were obtained at 60 mg ⋅ l-1 CaCO3, the variation of water hardness did not induce any significant changes in the other rheological parameters. The use of relatively high concentrations of TSPP in the leaching water contributed to the achievement of high values of breaking deformation, though beyond 2.5 g ⋅ l-1 a detrimental effect on breaking force was observed, and consequently also on gel strength.