LF 1H NMR T2 relaxation rate as affected by water addition, NaCl and pH in fresh, frozen and cooked minced hake

Abstract

Low-Field Nuclear Magnetic Resonance of proton transverse relaxation signal (T 2 ) was monitored in hake (Merluccius merluccius) mince with different thermal histories (fresh, frozen, cooked) as affected by pH, water and NaCl addition, and it was related to water holding capacity (WHC). Modifications of T 2 signals were found in terms of changes in relaxation times and relative abundance of the relaxation components. The relaxation rate of the major component (1/T 21 ) increased significantly upon frozen storage or pH increase, whereas water or NaCl addition had the opposite effect. WHC decreased with freezing or water addition and increased with NaCl or basic pH; thus, T 2 and WHC best correlated when each factor was analysed separately. Linearity found for pH and protein concentration with 1/T 21 was consistent with chemical exchange being responsible for these changes. The significance of these results for technological situations where compositional and biochemical changes are occurring is discussed.

Changes in physicochemical properties and myofibrillar protein properties in grass carp salted by brining and injection

“…But Duflot et al . (2019) found the entrapped water decreased after salting. This could attribute to the higher salt content and different raw material, which led to the water losing from muscle.…”

Gelation and microstructural properties of fish myofibrillar protein gels with the incorporation of l‐lysine and l‐arginine at low ionic strength

“…the inverse of the relaxation time, depends on exchange processes between water and surfaces which could be considered to be protein molecules in the present study. 29,30 The surface-to-volume ratio determines the relaxation rate and, accordingly, an increase in the distance between the thin and thick filaments is expected to result in an increase in the relaxation time. 29 Therefore, the increase in T 21 relaxation time was caused by a swelling of the myofilament lattice with increasing ionic strength.…”

Emerging Techniques for Differentiation of Fresh and Frozen–Thawed Seafoods: Highlighting the Potential of Spectroscopic Techniques

“…In the field of fish products characterization, for example, proton NMR relaxometry has proven to be a powerful technique to provide information on inherent muscle water and water-holding capacity (WHC), which are fundamental parameters in perception during food consumption [ 103 ]. In this regard, it is interesting to highlight the study of Duflot and collaborators [ 104 ] on the monitoring of the Low-Field (LF) 1 H NMR T 2 (proton transverse relaxation signal) relaxation rate in minced hake with different thermal treatments (fresh, frozen, and cooked) taking into account all other parameters that can affect this kind of signal (pH, NaCl, and protein concentration). The authors correlated T 21 (not significantly correlated), T 22 (R 2 = 0.469, significant at p = 0.05) relaxation times, and their corresponding maximum amplitudes A 21 (R 2 = 0.774, significant at p = 0.01) and A 22 (R 2 = 0.760, significant at p = 0.01) with WHC, and they also found that WHC decreased and that the relaxation rate of the major component increased upon frozen storage [ 104 ].…”

“…In this regard, it is interesting to highlight the study of Duflot and collaborators [ 104 ] on the monitoring of the Low-Field (LF) 1 H NMR T 2 (proton transverse relaxation signal) relaxation rate in minced hake with different thermal treatments (fresh, frozen, and cooked) taking into account all other parameters that can affect this kind of signal (pH, NaCl, and protein concentration). The authors correlated T 21 (not significantly correlated), T 22 (R 2 = 0.469, significant at p = 0.05) relaxation times, and their corresponding maximum amplitudes A 21 (R 2 = 0.774, significant at p = 0.01) and A 22 (R 2 = 0.760, significant at p = 0.01) with WHC, and they also found that WHC decreased and that the relaxation rate of the major component increased upon frozen storage [ 104 ]. Differently, the study of Shumilina and others is more pertinent to the discrimination between fresh and thawed products.…”