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Apparent Activation Energy of Viscous Flow in Pectin Jellies
Author(s) -
WALTER REGINALD H.,
SHERMAN RUTH M.
Publication year - 1981
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1981.tb03027.x
Subject(s) - pectin , flow (mathematics) , mechanics , chemistry , flow properties , thermodynamics , food science , physics
A change of state in a cooling jelly sol is preceded by a narrow temperature interval of viscous flow that may be measured, in order to compute the activation energy of such flow. The contribution of decreasing temperatures to the viscosity‐increase was 10 6 times greater than that of time. The apparent activation energy of viscous flow in citrus and apple jelly was found to be of the same order of magnitude, 10 4 cal/mole. Of the pectins studied, those that were commercially designated as slow‐setting tended to have a higher activation energy than those that were rapid‐setting. The flow pattern of some jellies, notably from pure citrus and rapid‐set pectins, was characterized by a different activation energy at high and low temperatures.