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COMPARISON OF STEADY SHEAR RHEOLOGICAL PROPERTIES AND SMALL AMPLITUDE DYNAMIC VISCOELASTIC PROPERTIES OF FLUID FOOD MATERIALS
Author(s) -
BISTANY KAREN L.,
KOKINI JOZEF L.
Publication year - 1983
Publication title -
journal of texture studies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.593
H-Index - 54
eISSN - 1745-4603
pISSN - 0022-4901
DOI - 10.1111/j.1745-4603.1983.tb00338.x
Subject(s) - viscoelasticity , rheology , materials science , viscosity , thermodynamics , amplitude , shear (geology) , shear rate , shear flow , nonlinear system , mechanics , composite material , physics , optics , quantum mechanics
Small amplitude dynamic viscoelastic properties of apple butter, mustard, tub margarine, and mayonnaise are compared with their respective properties in steady shear flow in the range of shear rates and frequencies of 0.1‐100 sec −1 using a Rheometrics Mechanical Spectrometer. Comparison of dynamic and steady viscosities shows that dynamic viscosities (η*) are much larger than steady viscosities (η). Consequently the Cox‐Merz rule is not obeyed. Moreover the obvious nonlinearity suggests that shift‐factor type relationships are not obeyed either. The in‐phase (η') component of the dynamic viscosity shows similar behavior when compared to the steady viscosity (η). Comparison of G′/ω 2 and Ψ 1 also suggests that any of the results predicted by classical theories of viscoelasticity are not obeyed. G'/ω 2 is always much larger than Ψ 1 and the relationship between these two material functions is nonlinear.