Abstract
The correlations between sensory and instrumental textural qualities of fish muscles were investigated using raw and cooked samples of three fish species (Skipjack, Yellowtail, Yellowfin tuna). The force induced by the columnar plunger at strain=50% and the elastic modulus at large strains (30-70%), correlated with sensory att ribute of "Firm-soft" in raw and cooked muscles (P<0.01), while the penetration depth of needle, the force induced by the columnar plunger at strain=50%, and the elastic modulus at large strains (30 and 70%) correlated with sensory attribute of "Wet-dry" (P<0.01). The macrostructure of muscle, especially the myoseptum, affected the result produced by plate-shaped plunger, and the correlation between the force at strain=50%and the sensory attributes of "Firm-soft". and "Wet-dry" was significant at P<0.05 level but not significant at P<0.01 level. The creep curves were analysed by a five-element and four-component model. The R1 component represented the recoverable instantaneous deformation. The R2 component represented the recoverable Voigt model. The P component represented the non-recoverable instantaneous deformation plus the non-recoverable Voigt model. The N component represented the Newtonian viscous flow. When these fish muscles were cooked, the combination of R1+R2 increased and P decreased in percentage expression. This result means that the main contributor to total deformation was plasticity (P) in the raw muscles but was elasticity (R1+R2) in the cooked muscles. The R1 component in percentage expression correlated with sensory attributes of "Elastic-plastic" and "Compact-flaky" at P<0.05 1evel. In all sensory attributes, the cooked muscle of yellowtail was extremely different from the cooked muscles of sklpjack and yellowfin tuna. This difference is partly due to the high lipld content of yellowtail muscle.
