Effects of cold air dehydration on icefish water dynamics and macromolecular oxidation measured by low-field nuclear magnetic resonance and magnetic resonance imaging.

We have used low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging to measure water dynamics and migration, color, and texture profile (TPA) of icefish dried with hot and cold air methods. Relaxation time of T21, T22, and T23, and the peak area of A22 and A23 decreased significantly during drying. The water signal intensity decreased from the surface to inner regions during drying. Color parameters of L* and b* values increased significantly, TPA parameters of hardness increased, cohesiveness decreased significantly, and moisture content decreased significantly during drying. We observed correlations between the moisture content, TPA, color, and NMR parameters. In addition, we found lower thiobarbituric acid reactive substances and carbonyl content of the dried icefish with cold air compared with hot air. The cold air drying method yielded better sensory quality, and LF-NMR was a useful nondestructive method to determine the degree of drying and the quality of icefish.