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Comparison of Steady Shear and Dynamic Viscoelastic Properties of Guar and Karaya Gums
Author(s) -
MILLS PATRICIA L.,
KOKINI JOZEF L.
Publication year - 1984
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1984.tb13654.x
Subject(s) - viscoelasticity , viscosity , shear stress , guar gum , guar , shear rate , thermodynamics , shear (geology) , materials science , relative viscosity , chemistry , composite material , physics , biochemistry
Steady shear and small amplitude dynamic viscoelastic properties of suspensions of guar gum and gum karaya in the range of shear rates/frequencies between 0.1 and 100 set −1 were compared. For all concentrations of guar at small shear rates/frequencies steady viscosity (η) is equal to dynamic viscosity (η ′ ) when corresponding shear rates and frequencies are equal. At large shear rates, steady viscosity (η) is equal to complex viscosity (η*); primary normal stress coefficient (ψ 1 ) is approximately equal to (2η″/ω). For gum karaya, it was shown that (η″/ω) is nonlinearly related to primary normal stress coefficient (ψ 1 ) and dynamic viscosity (η′) is nonlinearly related to steady viscosity (η).