Quantitative MRI in Food Science & Food Engineering

Magnetic Resonance Imaging (MRI) is a nondestructive and noninvasive technique that can be used to acquire two-dimensional and even three-dimensional images of biological products, even if they are opaque systems. The signal of each voxel depends on the physical properties of the sample such as proton density, relaxation times, temperature, diffusion, flow, and local differences in magnetic susceptibility. The information within the images can then be manipulated and used for spatially resolved measurements of concentration, structure, temperature, velocity, and diffusivity. In this article, the potential of MRI for the investigation of food products and food processing is illustrated by several examples. These examples include the characterization of vegetable and plant structure and the quantification of water and fat distribution in meat and dairy products. Moreover, the ongoing investigations of concentration and structural changes induced by food processes (which require specific devices to manage the temperature, air flow, and pressure directly in the MRI coil) are described. Keywords: fruit; vegetable; dairy; cereal; meat; fish; bread; fat; temperature; diffusion; structure; cooking; ripening; draining; swelling; freezing