Viscoelastic properties of Bologna sausages by dynamic methods

A series of sequential oscillatory dynamic tests was able to characterise the different stiffness of a few commercial high-quality Bologna sausages. Independently of their formulation, all samples were characterised as linear viscoelastic solids at strain amplitudes smaller than 1.3-8.1%. Using Friedrich and Heymann theory [J. Rheol. 32 (1988) 235], the study of the frequency dependence of the complex shear modulus (G(*)) permitted their protein network to be characterised in terms of a practically constant order of the relaxation function a (=0.10 +/- 0.01) and a composition-dependent stiffness parameter (A(alpha)). This was also confirmed by a validation test on another sample of Bologna sausage of different composition. By referring to fat-rich specimens A. might be useful for distinguishing between products of different composition and sensory properties. (C) 2003 Elsevier Ltd. All rights reserved.