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A study of gelatin gelation by Fourier transform mechanical spectroscopy

Hawkins, K; Lawrence, M; Williams, P R; Williams, R L

Authors

K Hawkins

M Lawrence

P R Williams

R L Williams



Abstract

This paper reports the results of experiments which were designed to test the hypothesis that the recording of anomalous values of rheological exponents in the gelation of gelatin may, under some circumstances, be due to inappropriate rheometry. Results obtained from stress relaxation tests and oscillatory shear frequency sweeps are compared with the time-resolved results of oscillatory shear measurements based on Fourier Transform Mechanical Spectroscopy (FTMS) which is used to identify the Gel Point. The experiments reported herein involve gelatin concentrations and temperatures which result in gel times in the range ca. 102–104 s, corresponding to the range of fast and slow gelation conditions reported elsewhere. Within this range, under conditions of appropriately low sample mutation number in our FTMS experiments, the values of the relaxation exponent α obtained at the Gel Point are found to be essentially independent of temperature and concentration, with a value of α ∼ 0.69. The results reported herein establish the rheometrical conditions under which rapid gelation produces anomalously low values of α and we conclude that the appearance of low α values, in our experiments, can be attributed to inappropriate rheometrical procedures.

Citation

Hawkins, K., Lawrence, M., Williams, P. R., & Williams, R. L. (2008). A study of gelatin gelation by Fourier transform mechanical spectroscopy. Journal of Non-Newtonian Fluid Mechanics, 148(1-3), 127-133. https://doi.org/10.1016/j.jnnfm.2007.05.016

Journal Article Type Article
Online Publication Date Jun 5, 2007
Publication Date 2008-01
Deposit Date Aug 1, 2016
Journal Journal of Non-Newtonian Fluid Mechanics
Print ISSN 0377-0257
Electronic ISSN 0377-0257
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 148
Issue 1-3
Pages 127-133
DOI https://doi.org/10.1016/j.jnnfm.2007.05.016
Keywords Gel point, FTMS, gelatin, gelation, stress relaxation, scaling theories, physical gels,
Public URL http://researchrepository.napier.ac.uk/Output/320644