1 H and 23 Na MRI studies of Atlantic salmon ( Salmo salar) and Atlantic cod (Gadus morhua) fillet pieces salted in different brine concentrations

• Published in: Journal of the Science of Food and Agriculture
• Main Authors: Veliyulin, Emil, Aursand, Ida G
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2007
• Subjects: atlantic cod; Atlantic salmon; Gadus morhua; Salmo salar
• Online Access: http://dx.doi.org/10.1002/jsfa.3030; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjsfa.3030; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jsfa.3030

Abstract BACKGROUND: Applicability of magnetic resonance imaging (MRI) to quantitative analysis of sodium in salted fish products is usually impaired by the partial 23 Na MRI ‘invisibility’ phenomena as well as high investment costs of the MRI equipment. RESULTS: Salmon and cod fillet pieces, unsalted and brine salted (50, 100, 150, 200 and 250 g kg −1 NaCl) for 48 h, were studied using 1 H and 23 Na MRI. Based on MRI results, T 1 and T 2 relaxation times were calculated for 1 H and the T 2 time for 23 Na nuclei. In addition, water diffusion images for all fillet samples and reference brine solutions were obtained. Variation of the nuclear magnetic resonance relaxation times and water diffusion constants with brine concentration is discussed in terms of the muscle structural changes. Sodium MRI visibility factors for the MRI method used were determined for all fish samples. CONCLUSION: Observed changes in proton and sodium NMR relaxation times with the salt content reflect complex counteraction of several factors related to the muscle structural changes. Sodium MRI visibility factors appear to be dependent on a number of experimental factors in a complex matter, making quantitative sodium analysis by the MRI technique used non‐trivial. Copyright © 2007 Society of Chemical Industry