Profiles of gelling characteristics of myofibrillar proteins extracted from chicken breast: Effects of temperatures and phosphates

The systematic effects of temperatures and phosphates (single and compound forms) on gelling characteristics of myofibrillar proteins (MPs) extracted from chicken breast were investigated by texture analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, low-field nuclear magnetic resonance (NMR), scanning electron microscopy, and rheology. Heating to 60 degrees C and 80 degrees C induced the formation of an elastic and hard MP gel, and meanwhile compound phosphate (CP) enhanced gel elasticity and hardness. At 80 degrees C, the maximum elasticity and hardness of MP gels were determined as 0.81 +/- 0.01 and 0.86 +/- 0.02 N respectively. Compared to high temperature (100 and 120 degrees C) groups, the relative composition percentage of immobilized water reached a higher level for low temperature (60 and 80 degrees C) groups, determined as 95.15 +/- 1.07% and 93.40 +/- 1.02% respectively, indicating a better water-holding capacity. Raman and low field NMR analysis showed that low temperatures determined the affinity between moisture and MPs, while phosphates may help to protect gels from destruction caused by high temperatures. Hexametaphosphate and pyrophosphate as the composition of CP were liable to produce a desirable MP cross-linking network compared to tripolyphosphate. In addition, CP could strengthen the rheological viscoelasticity of MP gels formed at 80 degrees C.