Electron Spin Resonance (ESR)
ESR
Electron spin resonance spectroscopy (ESR) or electron paramagnetic
resonance spectroscopy (EPR) as the technique is often also called, can be
used to study a number of food related phenomena:
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Oxidative changes in foods
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Testing stability of foods towards oxidation
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Mobility of molecules in foods
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Measurement of oxygen levels in microscopic domains of foods (oximetry)
ESR spectroscopy detects radicals which are molecules with unpaired
electrons. Radicals often appear in foods and other types of biological
materials as short-lived intermediates during the oxidative reactions that
result in oxidation of lipids, proteins, vitamins, and other important food
components.
The line shapes of ESR-signals are sensitive to the physical molecular
environment of the radicals. Analysis of ESR line shapes can give
information about physical properties at a molecular level such as
molecular mobility, polarity, or the presence of paramagnetic molecules
(e.g. oxygen).
ESR-Instruments
The Bruker and Magnettech instruments can be used for studies of
low-temperature and light induced reactions.
Lisbet S. Christensen, - siden er sidst opdateret d.2. april 2009