NMR Relaxometry Applied to Food Samples
Pp. 151-176 (26)
Maria Ines Bruno Tavares
Nuclear magnetic resonance through the use of proton relaxometry measures
the time needed by a population of spins once in the external magnetic field to recover
from a resonant radiofrequency excitation. Generally, two relaxation parameters can be
determined to describe the evolution of the spins system to the equilibrium state.
Proton spin-lattice relaxation time with a time constant, T1H, and proton spin-spin
relaxation time, with a time constant, T2H, are useful for elucidating molecular
dynamics of complex solid materials, like food samples, for example. These parameters
are of great interest because they are often used to obtain information on molecular
mobility of molecules ranging from small molecular groups and domains size.
Differences between values obtained for different samples can be used to evaluate
changes in the molecular mobility in the food systems like the moisture absorption and
water and oil distribution. Many studies can be done in food samples employing
relaxation data, such as: cooking, food storage, storage processes, validity time of
flours, major constituents and anti- oxidant in oils and so on.
Food samples, Food storage, Molecular mobility, NMR relaxometry,
Nuclear Magnetic Resonance, Storage processes.
Institute of Macromolecules, Federal University of Rio de Janeiro, Av. Horacio Macedo, 2030, Block J, CT, Fundão Island, Rio de Janeiro, RJ, CEP 21941-598, Brazil.