29C-17 |
Viscoelastic properties of pressurized and heat-treated surimi gels made from Alaska pollock (Theragra chalcogramma) and Pacific whiting ( Merluccius productus) |
G. TABILO-MUNIZAGA and G. V. Barbosa-Cánovas. Dept. of Biological Systems Engineering, Washington State Univ., PO Box 646120, Pullman, WA 99164-6120 The gelation of raw surimi is the process used to manufacture surimi-based products. Gelation is commonly induced by heat treatment but nowadays HHP is becoming an alternative to inducing gelation, without loss in nutritional and textural characteristics. Gelation of Alaska pollock and Pacific whiting surimi gels under high hydrostatic pressure (400MPa and 650MPa, 10 min) and under heat treatment (90°C, 40 min), combined with egg white and/or potato starch, was studied from a rheological point of view. An amplitude sweep, frequency sweep, and creep/recovery tests were carried out to obtain their viscoelastic parameters. Though additives did not affect the viscoelastic properties of surimi gels, pressure did. G’ values were larger than G” values. A significant reduction of G’ values was observed when surimi gels were pressurized regardless of pressure level (P<0.05) (the lower the pressure the higher the elasticity of the gels). The phase angle for surimi gels was practically constant (d~10o), indicating consistent solid-like behavior over the entire frequency range. Moreover, the rigidity of gels observed from compliance data [J0 (1/Pa)] showed higher rigidity in gels pressurized and heat-treated without additives (P<0.05). On the other hand, pressure treatment significantly (P<0.05) increased the elastic recovery response (over 85%) regardless of pressure level and the source of surimi gels. Heat-treated gels showed a lower elastic response (~76%). The elastic responses of pressurized surimi gels were close to 90%, indicating a good viscoelastic response, typical of viscoelastic materials. High hydrostatic pressure is an interesting alternative to thermal treatments for inducing gelation and potentially can be used to improve the processing and development of surimi seafood products.
Session 29C, Food Engineering: Rheology and texture
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