ABSTRACT

This chapter covers the basic nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) methodologies, and discusses use of NMR and MRI to study moisture migration, proton mobility, and glass transition in bread and other baked products. Many nuclei spin about an axis, and the spinning generates a magnetic field known as magnetic moment. Like a normal magnet bar, this magnetic moment has a north and a south pole, which is called nuclear magnetic dipole. MRI is an extension of NMR. It provides additional spatial information regarding the spins. The MRI system is designed to excite and receive signals from a single point, line, plane, or three-dimensional volume in a sequential manner. The point and line scanning methods are inefficient and have been superseded by the more efficient two- and three-dimensional methods.