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Low shear rheology of concentrated tomato products. Effect of particle size and time

Bayod, Elena LU ; Mansson, Pernilla; Innings, Fredrik LU ; Bergenståhl, Björn LU and Tornberg, Eva LU (2007) In Food Biophysics 2(4). p.146-157
Abstract
Time-dependent rheological properties of three tomato paste suspensions in the concentration range of 200-1,000 g paste/kg suspension have been investigated by using the vane geometry at shear rates gamma < 10 s(-1). Creep tests were conducted to analyze the influence of the level of stress on the rheological behavior of the samples before and after homogenization. The experimental results indicate that the suspensions exhibit an elastic behavior at long times and relatively low stresses, which proves that this type of material can be characterized by a yield stress (sigma(y)). Applying stresses just beyond the yield stress, an initial rheopectic behavior appeared. This increase in viscosity at low deformations was markedly larger after... (More)
Time-dependent rheological properties of three tomato paste suspensions in the concentration range of 200-1,000 g paste/kg suspension have been investigated by using the vane geometry at shear rates gamma < 10 s(-1). Creep tests were conducted to analyze the influence of the level of stress on the rheological behavior of the samples before and after homogenization. The experimental results indicate that the suspensions exhibit an elastic behavior at long times and relatively low stresses, which proves that this type of material can be characterized by a yield stress (sigma(y)). Applying stresses just beyond the yield stress, an initial rheopectic behavior appeared. This increase in viscosity at low deformations was markedly larger after homogenization, and this difference was attributed to changes in the aspect ratio, shape, and orientation of the particles induced by homogenization. These structural changes were also reflected in the transient viscosity when the samples were subjected to larger stresses (sigma >>sigma y): before homogenization the suspensions exhibited a steady-state viscosity at large deformations, whereas after homogenization, the transient viscosity continuously decreased. That behavior was attributed to flocculation of the particles. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
homogenization, rheology, yield stress, tomato paste, time-dependency
in
Food Biophysics
volume
2
issue
4
pages
146 - 157
publisher
Springer
external identifiers
  • wos:000251092400003
  • scopus:36549013699
ISSN
1557-1866
DOI
10.1007/s11483-007-9039-2
language
English
LU publication?
yes
id
aeb2c5cf-ce8f-4e02-af76-26b1915f1f78 (old id 969148)
date added to LUP
2008-01-29 13:12:02
date last changed
2017-08-20 03:37:07
@article{aeb2c5cf-ce8f-4e02-af76-26b1915f1f78,
  abstract     = {Time-dependent rheological properties of three tomato paste suspensions in the concentration range of 200-1,000 g paste/kg suspension have been investigated by using the vane geometry at shear rates gamma &lt; 10 s(-1). Creep tests were conducted to analyze the influence of the level of stress on the rheological behavior of the samples before and after homogenization. The experimental results indicate that the suspensions exhibit an elastic behavior at long times and relatively low stresses, which proves that this type of material can be characterized by a yield stress (sigma(y)). Applying stresses just beyond the yield stress, an initial rheopectic behavior appeared. This increase in viscosity at low deformations was markedly larger after homogenization, and this difference was attributed to changes in the aspect ratio, shape, and orientation of the particles induced by homogenization. These structural changes were also reflected in the transient viscosity when the samples were subjected to larger stresses (sigma &gt;&gt;sigma y): before homogenization the suspensions exhibited a steady-state viscosity at large deformations, whereas after homogenization, the transient viscosity continuously decreased. That behavior was attributed to flocculation of the particles.},
  author       = {Bayod, Elena and Mansson, Pernilla and Innings, Fredrik and Bergenståhl, Björn and Tornberg, Eva},
  issn         = {1557-1866},
  keyword      = {homogenization,rheology,yield stress,tomato paste,time-dependency},
  language     = {eng},
  number       = {4},
  pages        = {146--157},
  publisher    = {Springer},
  series       = {Food Biophysics},
  title        = {Low shear rheology of concentrated tomato products. Effect of particle size and time},
  url          = {http://dx.doi.org/10.1007/s11483-007-9039-2},
  volume       = {2},
  year         = {2007},
}