Mechanisms of transverse relaxation of water in muscle tissue

Abstract

Nuclear magnetic resonance (NMR), and in particular transverse relaxation (T2), has been used to characterize meat and seafood products for decades. Despite many years of research, it is still not possible to reproducibly correlate the transverse relaxation of muscle foods to attributes that determine their quality and value. Instead of directly trying to interpret the T2 spectrum itself, typically chemometrics is used to try to relate the relaxation distributions to other measured properties on the sample. As muscle tissue is a porous medium, it is tempting to use equations developed to analyze other porous systems to provide a more direct, quantitative description of the tissue. However, the standard equations used to characterize porous materials have been developed for predominantly geological systems. This article discusses the foundations of transverse relaxation theory in porous media and the challenges that arise when attempting to adapt the equations to a biological system like tissue.One of the biggest issues that needs to be overcome before porous media theory can be reliably applied to characterize meat and seafood is to determine the source of relaxivity in the tissue. In order to better understand how the NMR signal originates, T2, diffusion, T1-T2 correlation and T2-T2 exchange experiments were performed on Atlantic cod (Gadus morhua) tissue in a variety of states (e.g. fresh, thawed, homogenized, etc.). In the literature, typically four T2 peaks are reported for meat and seafood samples. Results of this study

Rehydration characteristics of dried icefish (Salangidae) with different drying methods by low‐field nuclear magnetic resonance and magnetic resonance imaging

“…With the extension of time, the proportion of immobilized water did not increase significantly in cold air drying groups ( p < 0.05), while the proportion in those dried by hot air still maintained a high growth. The larger T 2 transverse relaxation time, the smaller binding force of water, which is more likely to be lost (Anderssen & McCarney, 2022). At the initial stage of rehydration, the dried icefish absorbed a large amount of water, the proportion of bound water decreased significantly and migrated to immobilized water.…”

“…The larger T 2 transverse relaxation time, the smaller binding force of water, which is more likely to be lost (Anderssen & McCarney, 2022).…”

Changes in Textural Quality and Water Retention of Spiced Beef under Ultrasound-Assisted Sous-Vide Cooking and Its Possible Mechanisms

“…With the extension of cooking time, T 1 relaxation time increased gradually in USV groups, but it was significantly lower ( p < 0.05) than in CT and SV groups. The prolongation of T 1 relaxation time meant more free water migrated from the muscle, which might be attributed to the weakening water–protein interaction caused by long-time heating [ 34 , 35 ]. T 2 relaxation time significantly decreased ( p < 0.05) in USV groups heating for 40~80 min, but significantly increased ( p < 0.05) at 100~120 min of heating.…”

Ultrafast transverse relaxation exchange NMR spectroscopy

“…Nuclear magnetic resonance spectroscopy (NMR) is used in the investigation of molecular motion in a noninvasive way, without tracers and it can be used in studying optically opaque samples. 3 Different multidimensional NMR exchange methods, such as exchange spectroscopy (EXSY), 4 diffusion exchange spectroscopy (DEXSY) 5,6 and T 2 -T 2 relaxation exchange spectroscopy (REXSY), [7][8][9] have been exploited in the analysis of molecular exchange processes. For example, the REXSY method has been used to investigate exchange in urea-water systems, 7,10 human cortical bone, 11 geopolymers 12 and shale, 13 track poreto-pore exchange, 14 asphaltene adsorption, 15 and water exchange in myelinated nerves 16 and study aggregation of ionic liquids.…”

“…After that, the encoded data are read using the principles of magnetic resonance imaging (MRI). 8,9 As a result, the two-dimensional data is collected in a single scan and is analogous to the conventional, slow, counterpart.…”