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An NMR pulsed field gradient study of the electrical and conventional heating of carrot
Author(s) -
STAPLEY ANDREW G. F.,
GONÇALVES JOSÉ A. SOUSA,
HOLLEWAND MICHAEL P.,
GLADDEN LYNN F.,
FRYER PETER J.
Publication year - 1995
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.1995.tb01411.x
Subject(s) - pulsed field gradient , diffusion , chemistry , analytical chemistry (journal) , permeability (electromagnetism) , significant difference , nuclear magnetic resonance , thermodynamics , chromatography , physics , mathematics , membrane , biochemistry , statistics
Summary Experiments have been carried out using pulsed field gradient NMR to characterize the self‐diffusion of water within samples of carrot, both uncooked and cooked by either volumetric electrical or conventional heating. The method detected the presence of structure within uncooked carrot, and the disappearance of the structure on cooking. The NMR data were fitted to two models: (i) an analytical solution for diffusion between impermeable barriers and (ii) a numerical solution to the more physically realistic situation of diffusion between permeable barriers. The barrier spacings obtained with raw carrot data using both methods (i) and (ii) were consistent with cell sizes found in carrots. The effect of cooking on the model fit was either an increase in barrier spacing (method i), or an increase in barrier permeability (method ii). There was a statistically significant difference between samples cooked electrically and conventionally, but this was much less than the difference between cooked and uncooked material.