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Development of Rheometry for the Characterisation of Rapidly Gelling Strain Sensitive Materials / Alex Bulpitt

Swansea University Author: Alex Bulpitt

  • E-Thesis – open access under embargo until: 1st May 2029

DOI (Published version): 10.23889/SUthesis.66309

Abstract

The rheological analysis and gel point determination of rapidly gelling strain sensitive materials presents many challenges. High levels of sample mutation and low torque responses associated with the small strains required to maintain linear viscoelastic measurements lead to erroneous rheological d...

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Published: Swansea, Wales, UK 2024
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Hawkins, Karl M. ; Curtis, Daniel J.
URI: https://cronfa.swan.ac.uk/Record/cronfa66309
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last_indexed 2024-05-06T14:22:34Z
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spelling v2 66309 2024-05-06 Development of Rheometry for the Characterisation of Rapidly Gelling Strain Sensitive Materials 9b3da07bf1df299f75e51dced7d50692 Alex Bulpitt Alex Bulpitt true false 2024-05-06 CHEG The rheological analysis and gel point determination of rapidly gelling strain sensitive materials presents many challenges. High levels of sample mutation and low torque responses associated with the small strains required to maintain linear viscoelastic measurements lead to erroneous rheological data. Such artefacts can be overcome by applying high frequency multiwave tests such as Fourier Transform Mechanical Spectroscopy (FTMS), decreasing measurement times, and increasing torque response. However, operating at high frequencies can invalidate the assumption of performing measurements in the gap loading regime, introducing sample inertia. Current methods of correcting for sample inertia used by rheometer software involves an iterative process and knowledge of parameters including sample density and shearing gap. Herein, we find a discrepancy between the rheometer measured gap and the actual gap. This introduces errors in the inertia correction and calculated data, including parameters at the gel point. Therefore, a novel procedure for sample inertia correction is developed and validated for high frequency discrete sweeps and FTMS, based on finding an accurate gel point using bovine gelatine. The correction procedure was used as a tool in the determination of gel points, and its application for strain sensitive, rapidly gelling systems (gel times < 30 s) is demonstrated. The inertia correction procedure has the potential for characterising any gelling material where the linear range is small or unknown, through the application of low levels of strain. Finally, the gel point of a rapidly gelling, hybrid carrageenan-based gel was determined. This gel is used in the vegetarian softgel encapsulation process, a process with inherent difficulties due to changing rheological properties of the gel. Elucidation of the rheological behaviour at the gel point may prove useful as a marker for determining end properties of the softgels and serves as a consistency check for product quality at the earliest possible stages. E-Thesis Swansea, Wales, UK Rheology, fluid inertia, strain sensitive rheometry, rapid gelation, fluid inertia correction, gel point, gelatine, carrageenan 1 5 2024 2024-05-01 10.23889/SUthesis.66309 COLLEGE NANME Chemical Engineering COLLEGE CODE CHEG Swansea University Hawkins, Karl M. ; Curtis, Daniel J. Doctoral Ph.D KESS 2 KESS 2 2024-05-06T15:40:05.6595052 2024-05-06T15:18:53.7676467 Faculty of Medicine, Health and Life Sciences Swansea University Medical School - Biomedical Science Alex Bulpitt 1 Under embargo Under embargo 2024-05-06T15:28:47.0020560 Output 5251282 application/pdf E-Thesis – open access true 2029-05-01T00:00:00.0000000 Copyright: The Author, Alex Bulpitt, 2024. true eng
title Development of Rheometry for the Characterisation of Rapidly Gelling Strain Sensitive Materials
spellingShingle Development of Rheometry for the Characterisation of Rapidly Gelling Strain Sensitive Materials
Alex Bulpitt
title_short Development of Rheometry for the Characterisation of Rapidly Gelling Strain Sensitive Materials
title_full Development of Rheometry for the Characterisation of Rapidly Gelling Strain Sensitive Materials
title_fullStr Development of Rheometry for the Characterisation of Rapidly Gelling Strain Sensitive Materials
title_full_unstemmed Development of Rheometry for the Characterisation of Rapidly Gelling Strain Sensitive Materials
title_sort Development of Rheometry for the Characterisation of Rapidly Gelling Strain Sensitive Materials
author_id_str_mv 9b3da07bf1df299f75e51dced7d50692
author_id_fullname_str_mv 9b3da07bf1df299f75e51dced7d50692_***_Alex Bulpitt
author Alex Bulpitt
author2 Alex Bulpitt
format E-Thesis
publishDate 2024
institution Swansea University
doi_str_mv 10.23889/SUthesis.66309
college_str Faculty of Medicine, Health and Life Sciences
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hierarchy_top_id facultyofmedicinehealthandlifesciences
hierarchy_top_title Faculty of Medicine, Health and Life Sciences
hierarchy_parent_id facultyofmedicinehealthandlifesciences
hierarchy_parent_title Faculty of Medicine, Health and Life Sciences
department_str Swansea University Medical School - Biomedical Science{{{_:::_}}}Faculty of Medicine, Health and Life Sciences{{{_:::_}}}Swansea University Medical School - Biomedical Science
document_store_str 0
active_str 0
description The rheological analysis and gel point determination of rapidly gelling strain sensitive materials presents many challenges. High levels of sample mutation and low torque responses associated with the small strains required to maintain linear viscoelastic measurements lead to erroneous rheological data. Such artefacts can be overcome by applying high frequency multiwave tests such as Fourier Transform Mechanical Spectroscopy (FTMS), decreasing measurement times, and increasing torque response. However, operating at high frequencies can invalidate the assumption of performing measurements in the gap loading regime, introducing sample inertia. Current methods of correcting for sample inertia used by rheometer software involves an iterative process and knowledge of parameters including sample density and shearing gap. Herein, we find a discrepancy between the rheometer measured gap and the actual gap. This introduces errors in the inertia correction and calculated data, including parameters at the gel point. Therefore, a novel procedure for sample inertia correction is developed and validated for high frequency discrete sweeps and FTMS, based on finding an accurate gel point using bovine gelatine. The correction procedure was used as a tool in the determination of gel points, and its application for strain sensitive, rapidly gelling systems (gel times < 30 s) is demonstrated. The inertia correction procedure has the potential for characterising any gelling material where the linear range is small or unknown, through the application of low levels of strain. Finally, the gel point of a rapidly gelling, hybrid carrageenan-based gel was determined. This gel is used in the vegetarian softgel encapsulation process, a process with inherent difficulties due to changing rheological properties of the gel. Elucidation of the rheological behaviour at the gel point may prove useful as a marker for determining end properties of the softgels and serves as a consistency check for product quality at the earliest possible stages.
published_date 2024-05-01T15:40:04Z
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score 11.013148

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