Magnetic resonance imaging and spectroscopy for food systems

The theory and applications of magnetic resonance (MR) imaging and spectroscopy in food research are reviewed in detail, with emphasis on internal quality evaluation and measurement of dynamic phenomena in food systems, such as colloidal stability, fat and water crystallization, and macroscopic diffusion of fat, water, solutes and solids, as well as rheological measurements. MR imaging and spectroscopy are based on magnetic properties of atomic nuclei (e.g. the proton), and allow the measurement of the motional freedom of species of atoms in various types of molecules. This technique is non-invasive and can be applied in real time to follow dynamic phenomena such as fluid flow, processing, moisture and fat migration during frying, liquid drainage in a foam, or fat crystallization in a biscuit. It provides a powerful tool to the food scientist for studying the physical properties of food systems or specific food components and their evaluation during various processes.