Numerical Simulation of Protein Denaturation of Scallop Adductors during Heating Based on Temperature Distribution and Water Status Distribution

Protein denaturation is the key point affecting quality attributes of the scallop adductors (SA) during thermal processing such as drying, sous-vide cooking and traditional cooking. It is of crucial importance to establish a kinetics model of protein denaturation and reveal its relationship with water status of SA for regulating the quality of SA with thermal processing. Protein denaturation kinetics parameters were obtained by using differential scanning calorimeter (DSC). Protein denaturation during heating was numerically simulated based on the temperature distribution and water status distribution. The water status and distribution was measured by using low-field nuclear magnetic resonance (LF-NMR). The result indicated that the initial and complete denaturation temperatures of myosin were 32.50 ℃ and 55.00 ℃, respectively. While the counterparts of actin were 51.25 ℃ and 77.50 ℃, respectively. Ultrasonic (US) pre-treatment improved thermal stability of protein because the denaturation temperature of myosin and action was increased by 3.75 ℃ compared to the control group. The relaxation time of the tightly bound water (T2b) and loosely bound water (T21) fluctuated with a narrow range (T2b 0.19~0.25 ms, T21 1.38~2.97 ms), and the immobilized water (T22) and free water (T23) decreased with the increase of protein denaturation degree. While the proportion of T22 decreased significantly, and that of T2b and T21 increased slightly, but the proportion of T23 remained a dynamic stable state. Compared to the control group, US pre-treatment resulted in a decrease in the T22 and its proportion. The denaturation of myosin and actin was negatively correlated with the free water, immobilized water and its proportion. Therefore, the denaturation degree of myosin and actin during heating can be non-destructively and quickly evaluated by monitoring the water status and distribution of SA.