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Rheological characterisation of thickened fluids under different temperature, pH and fat contents

Enrico Karsten Hadde (School of Chemical Engineering, University of Queensland, Brisbane, Australia)
Timothy Michael Nicholson (School of Chemical Engineering, University of Queensland, Brisbane, Australia)
Julie Ann Yvette Cichero (School of Pharmacy, University of Queensland, Brisbane, Australia)

Nutrition & Food Science

ISSN: 0034-6659

Article publication date: 9 March 2015

Abstract

Purpose

The purpose of this paper was to examine the rheological characterisation of thickened water under different temperature and pH conditions and thickened milk with different fat contents.

Design/methodology/approach

Beverages thickened with powdered thickeners are used in the medical management of individuals who suffer swallowing difficulties (dysphagia). Each individual requires a specific level of thickness to best meet the needs of their dysphagia. Although the level of thickness is defined, obtaining the correct consistency of thickened fluids is difficult. This is due to fluctuations associated with temperature and type of fluids to be thickened. Rheological characterisation of commercially available xanthan gum-based thickener was performed under different conditions of temperature, pH and fat contents.

Findings

The viscosity and the yield stress of thickened water was found to be unaffected by pH. Similarly, temperature did not affect the viscosity at a high thickener concentration, although it did at lower concentration levels. Conversely, viscosity and yield stress increased as fat levels increased in thickened milk. Furthermore, thickened water took less than 2 minutes to reach equilibrium viscosity, while thickened milk required approximately 15 minutes to reach equilibrium viscosity.

Practical implications

These findings have implications for the standing time required for different beverages before they are thickened to a consistency that has been deemed safe for the patient’s physiological needs. Additionally, it highlights that different liquid base substances required different amounts of thickener to achieve the same level of thickness.

Originality/value

Findings from this study confirms and explores the variability of thickened fluids under different conditions of temperature, pH and fat content for the medical management of dysphagia.

Keywords

Acknowledgements

This project was funded by Nestlé Medical Nutrition, Australia, which has a commercial interest in the production of texture-modified fluids. The funding organisation was not involved in the design of the project, its conduct or the writing and interpretation of the results. None of the authors have a financial interest in the sponsor company. The sponsor had no input into the preparation or approval of the manuscript. The authors also acknowledge the Occupational Trainee from LaSalle Beauvais, Candice Deblauwe for her assistance with the rheological measurement.

Citation

Hadde, E.K., Nicholson, T.M. and Cichero, J.A.Y. (2015), "Rheological characterisation of thickened fluids under different temperature, pH and fat contents", Nutrition & Food Science, Vol. 45 No. 2, pp. 270-285. https://doi.org/10.1108/NFS-06-2014-0053

Publisher

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Emerald Group Publishing Limited

Copyright © 2015, Emerald Group Publishing Limited