Rupture properties, such as yield stress (YS) and the limit of linear viscoelastic region (LLVER), of Alaska pollock surimi pastes and failure shear stress (FSS) of Alaska pollock surimi gels were measured at various moisture contents. The stress-stain behavior of surimi paste was measured by the small amplitude oscillatory shear test using a dynamic rheometer. The YS values and the applied stress at LLVER (ASLLVER) of surimi paste were analyzed based on the stress-strain behavior during stress sweep test at 0.1 Hz. The FSS of surimi gels measured by the Hamann Torsion Gelometer showed a strong correlation with the moisture content (r2 = 0.95). YS and ASLLVER showed strong correlations with the moisture contents (r2 = 0.94 and 0.94, respectively). Such good correlations found at varied moisture contents suggest that the rupture properties of surimi paste may help estimate the texture properties of gel products.
Texture properties play a major role in evaluating the quality of final products of surimi seafood, such as kamaboko and crabsticks. Failure shear stress from the torsion test is known as the most reliable value to reflect the hardness of surimi gels. Although the torsion test generates good correlations with sensory results, there are a few inevitable disadvantages: it possesses the complexity of measurements and the laborious sample preparation. Generally, the torsion test requires 1 day for gels and about 2 h for the testing specimen. Our study discovered a strong correlation of FSS of surimi gels with the rupture properties of surimi pastes, such as YS and the LLVER. Since the rupture properties of surimi pastes do not require gelation, it saves the testing time dramatically. Our new finding can be used to partially estimate the gel properties based on the paste properties, when enzymatic reactions in fish proteins are not considered.