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Evaluation of new methods and measuring systems for characterisation of flow behaviour of complex foods

Roos, H ; Bolmstedt, Ulf LU and Axelsson, Anders LU (2006) In Applied Rheology 16(1). p.19-25
Abstract
Conventional methods often impose difficulties when measuring the viscosity of fluids containing particles or fibres, e.g. tomato paste or fruit preparations, mainly due to the narrow gaps of the viscometer. In order to solve these problems different geometries have been developed, e.g. different mixer systems and wide gap double concentric cylinders. However, these can not be evaluated assuming a constant shear rate throughout the fluid. In this study, three different kinds of mixer systems have been studied; a small and a large paddle and a helix. For the mixer systems an average shear rate must be determined and a quotient between torque and shear stress must be found. in addition, a wide gap double concentric cylinder (DCC) was... (More)
Conventional methods often impose difficulties when measuring the viscosity of fluids containing particles or fibres, e.g. tomato paste or fruit preparations, mainly due to the narrow gaps of the viscometer. In order to solve these problems different geometries have been developed, e.g. different mixer systems and wide gap double concentric cylinders. However, these can not be evaluated assuming a constant shear rate throughout the fluid. In this study, three different kinds of mixer systems have been studied; a small and a large paddle and a helix. For the mixer systems an average shear rate must be determined and a quotient between torque and shear stress must be found. in addition, a wide gap double concentric cylinder (DCC) was examined and evaluated using two different methods. When evaluating the mixer systems a method based on the Couette analogy has been used successfully for a number of complex fluids, including prepared sauces and fruit samples containing particles of different size. The DCC has been evaluated using a numerical as well as an approximate method, both giving results of good accuracy. All systems had the limitation that no consistent results were obtained for tomato paste. However, when starch was added to the diluted tomato paste dispersion, satisfying results were once again obtained. (Less)
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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
food dispersions, tomato paste, rheology, food, double concentric cylinder, Couette analogy, mixer viscometer
in
Applied Rheology
volume
16
issue
1
pages
19 - 25
publisher
De Gruyter
external identifiers
  • wos:000237487600007
  • scopus:33645817523
ISSN
1430-6395
language
English
LU publication?
yes
id
2256762e-10f9-402d-910c-5c43ef8bd2ef (old id 409818)
alternative location
http://www.ar.ethz.ch/
date added to LUP
2016-04-01 11:34:10
date last changed
2023-08-31 23:08:57
@article{2256762e-10f9-402d-910c-5c43ef8bd2ef,
  abstract     = {{Conventional methods often impose difficulties when measuring the viscosity of fluids containing particles or fibres, e.g. tomato paste or fruit preparations, mainly due to the narrow gaps of the viscometer. In order to solve these problems different geometries have been developed, e.g. different mixer systems and wide gap double concentric cylinders. However, these can not be evaluated assuming a constant shear rate throughout the fluid. In this study, three different kinds of mixer systems have been studied; a small and a large paddle and a helix. For the mixer systems an average shear rate must be determined and a quotient between torque and shear stress must be found. in addition, a wide gap double concentric cylinder (DCC) was examined and evaluated using two different methods. When evaluating the mixer systems a method based on the Couette analogy has been used successfully for a number of complex fluids, including prepared sauces and fruit samples containing particles of different size. The DCC has been evaluated using a numerical as well as an approximate method, both giving results of good accuracy. All systems had the limitation that no consistent results were obtained for tomato paste. However, when starch was added to the diluted tomato paste dispersion, satisfying results were once again obtained.}},
  author       = {{Roos, H and Bolmstedt, Ulf and Axelsson, Anders}},
  issn         = {{1430-6395}},
  keywords     = {{food dispersions; tomato paste; rheology; food; double concentric cylinder; Couette analogy; mixer viscometer}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{19--25}},
  publisher    = {{De Gruyter}},
  series       = {{Applied Rheology}},
  title        = {{Evaluation of new methods and measuring systems for characterisation of flow behaviour of complex foods}},
  url          = {{http://www.ar.ethz.ch/}},
  volume       = {{16}},
  year         = {{2006}},
}