Correlation between in-line measurements of tomato ketchup shear viscosity and extensional viscosity
Artikel i vetenskaplig tidskrift, 2016

The viscosity and shear thinning behavior are essential characteristics of tomato ketchup. A real-time monitoring of those characteristics during processing is important to obtain a good quality of the final product and to reduce production waste. This work investigates the measurement of rheological in-line flow properties of tomato ketchup, using a real-time technique that combines ultrasound velocity profiling (UVP) and pressure difference (PD) assessment. In-line data were compared to those obtained off-line using a rotational viscometer. There was a poor correlation with the Bostwick measurement, whereas the flow curves calculated from flow velocimetry data were very similar to those measured off-line. The extensional viscosity of ketchup was determined through the measurement of Hyperbolic Contraction Flow; the curve followed a trend similar to that for the shear viscosity over the deformation rate investigated.


Extensional viscosity


Hyperbolic contraction flow


M. Berta

SIK – Institutet för Livsmedel och Bioteknik AB

J. Wiklund

SIK – Institutet för Livsmedel och Bioteknik AB

R. Kotze

SIK – Institutet för Livsmedel och Bioteknik AB

Cape Peninsula University of Technology

Mats Stading

Chalmers, Material- och tillverkningsteknik, Polymera material och kompositer

Journal of Food Engineering

0260-8774 (ISSN)

Vol. 173 8-14





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