Nuclear Magnetic Resonance: Principles

The many applications of nuclear magnetic resonance (NMR) to dairy products can be divided into three groups, according to the NMR technique used. The first group uses high-resolution NMR spectroscopy for the molecular study of dairy compounds such as casein,a-lactalbumin, b-lactoglobulin, lactose, and triacylglycerol. All possible nuclei (1H, 2H, 17O, 13C, or 31P) can be used to obtain molecular structures. The second group involves the application of magnetic resonance imaging (MRI) to dairy processing and the third group concerns studies based on NMR relaxation and diffusion measurements.Only MRI and NMR relaxation and diffusion applied to dairy products will be described in this article. We first discuss NMR and MRI techniques as such, with special emphasis on relaxation time parameters, and provide some examples of how NMR and MRI can be applied to dairy products and dairy processes.