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CONSISTENCY OF DISPERSED FOOD SYSTEMS AND ITS EVALUATION BY SQUEEZING FLOW VISCOMETRY
Author(s) -
CORRADINI MARIA G.,
PELEG MICHA
Publication year - 2005
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.1745-4603.2005.00034.x
Subject(s) - viscometer , rheology , materials science , consistency (knowledge bases) , shearing (physics) , mechanics , slip (aerodynamics) , composite material , rheometer , flow properties , solidity , viscosity , mathematics , computer science , thermodynamics , physics , geometry , programming language
In testing semiliquid foods, conventional viscometers have two major problems: slip and disruption of the specimen's microstructure upon its insertion into the narrow gap of the sensor. These two problems are almost completely eliminated when lubricated squeezing flow viscometry is used; slip becomes a prerequisite for a proper test and, because of the large initial distance between the plates, the specimen can be tested practically intact. The penalty is that with the instrumentation commonly available in food research and quality assurance laboratories, the method can only be used at fairly small rates. In squeezing flow viscometry, the overall consistency of the tested material can be expressed in terms of the apparent stress at a given specimen height and its “degree of solidity” by the residual apparent stress at a given specimen height, measured after more than a minute at relaxation. The method is sensitive enough to determine differences between semiliquid foods, to record changes in their rheological properties as a result of shearing and to monitor their ability to recover their consistency when left to rest. The method also allows to follow the structural development of foams during their formation and collapse, because of drainage, when left undisturbed.