Premium
PSEUDOPLASTIC AND RHEOPECTIC PROPERTIES OF A GLOBULAR PROTEIN (β‐LACTOGLOBULIN) SOLUTION 1
Author(s) -
PRADIPASENA PASAWADEE,
RHA CHOKYUN
Publication year - 1977
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.1745-4603.1977.tb01184.x
Subject(s) - shear rate , shearing (physics) , thixotropy , shear thinning , apparent viscosity , viscometer , rheology , materials science , reduced viscosity , viscosity , ionic strength , globular protein , whey protein , aqueous solution , chemistry , shear (geology) , chromatography , analytical chemistry (journal) , composite material , crystallography , organic chemistry
The apparent viscosity of β‐lactoglobulin solutions was studied as a function of shear rate using a cone and plate uiscometer (Ferranti‐Shirley Viscometer System). Aqueous buffered solutions (pH 7, ionic strength 0.04) containing up to 40% protein were subjected to a rate of shear between 800 and 17,000 sec‐1 . At protein concentrations of 5% and lower, the viscosity was independent of the shear rate or the time of shearing. At protein concentrations of 10% or higher, the viscosity decreased asymptotically with an increasing shear rate. At a constant shear rate, the viscosity of 10‐30%β‐lactoglobulin solutions increased with shearing time. However, this rheopectic property was not consistently observed but, rather, was dependent on the rate of shear at concentrations lower than 20%. A rheopectic hysteresis effect was observed for 10‐30% protein solutions whereas thixotropy was observed for 40% solutions. The rheopectic nature appeared to be the result of the permanent denaturation of protein characterized by UV absorption and gel filtration.