Characterization of ultrahigh pressure surimi gels and the role of selected additives

The main goal of this study was to evaluate color, texture, microstructure and rheological properties of ultra high pressure (UHP) surimi gels made from Alaska pollock (Theragra chalcogramma) and Pacific whiting (Merluccius productus) with or without potato starch and egg white, and to compare those gels with heat-induced surimi gels.; Pressure treatment improved whiteness of surimi gels as compared with heat-treated surimi gels, whereas additives did not. At 400 MPa, whiteness values were 10% higher than heat-induced surimi gels. However, at 650 MPa whiteness increased only 8%. Gel strength and hardness of surimi gels were higher in heat-induced gels than in pressurized ones. Gels scored the maximum of 5 in the folding test irrespective of pressure applied or additives. UHP Alaska pollock and Pacific whiting surimi gels, in all cases, exhibited good water binding capacity (WHC) (over ∼90%). WHC of Pacific whiting surimi gels at 400 MPa and 650 MPa with egg white, was higher than in heated gels.; Scanning electron microscopy demonstrated that surimi-egg white matrices were fibrous and homogenous with a three-dimensional network structure, whereas surimi-starch matrices exhibited a more compact and continuous network.; Though additives did not affect the viscoelastic properties of surimi gels, pressure did. The damping factor (tan δ) for surimi gels were practically constant, indicating consistent solid-like behavior over the entire frequency range under consideration. The compliance data J₀ (1/Pa) for Alaska pollock surimi gels as well as Pacific whiting surimi gels exhibited the highest value in pressurized and heat-induced gels without additives. The elastic recovery in UHP induced gels (over 85%) was significantly higher than heat-induced ones (∼76%) regardless of the pressure level or species.; Since UHP generates surimi gels with a fine surface and good elastic characteristics, it becomes an interesting alternative to thermal treatments, and it could be used to improve the processing of surimi seafood products either with conventional or novel formulations.