Rheological Analysis of Fish-Meat Gel Added Starch Using the Large-Deformation Theory

Abstract

The rheological properties offish-meat gel with or without starch were characterized by large-defor-mation tests. We conducted a compression test with up to 70% deformation. The results were analyzed by the Mooney-Rivlin equation: f=(2C₁+2C₂/λ)(λ-1/λ²), where f is the stress, λ is the draw ratio, and C₁ and C₂ are the constants. In Mooney-Rivlin plots of the case considered as two- and three-terms, the theoretical curves show excellent correspondence with experimental plots in the initial-strain region. To investigate the adding effect of wheat starch on the fish-meat gel's elasticity, the water amount added into sample was controlled by considering water-absorbing capacity of wheat starch at 60°C and 90°C. In doing so, the water content of each gel was adjusted to be the same. Here the effect of adding starch on the fish-meat gel's elasticity was interpreted by the Mooney-Rivlin equation. The result showed that the effect of added starch must be analyzed according to composition before and after heating. We thus obtained the tendency whereby the experimental values agreed with the theoretical values in the initial region.