Water dynamics changes and protein denaturation in surf clam evaluated by two-dimensional LF-NMR T1-T2 relaxation technique during heating process

Water dynamics and protein denaturation in surf clam during heating were studied by the two-dimensional low-field nuclear magnetic resonance (LF-NMR) T1-T2 relaxation technique. A significant change was found for clam around 80 °C and direct visualization of the water state change was provided by the magnetic resonance imaging. Principal components and heatmap analysis revealed that clam treated at 80–100 °C located at different region from those treated at 40–70 °C. The clams heated at 80 °C showed a maximum water holding capability, and significant microstructure change. The differential scanning calorimetry analysis indicated a denaturation of protein when the temperature was over 80 °C. The hardness and chewiness had a maximum value at 80 and 70 °C, respectively. The color parameter L* showed a significant increase when temperature was over 80 °C. This demonstrated that the T1-T2 technique has potential in evaluating water dynamics for surf clam during heating.