The study of protein conformation and hydration characteristics of meat batters at various phase transition temperatures combined with Low-field nuclear magnetic resonance and Fourier transform infrared spectroscopy

摘要

To get a thorough understanding of evolution of heat-induced gel in meat batters, water distribution, protein conformation and their chemical bonds at phase transition temperatures (20-74 degrees C) were investigated by Low-field NMR and FT-IR. Firstly, G' increased and tan delta decreased beyond 55 degrees C, when sol was completely changed into an elastic gel. Then water holding capacity (WHC) decreased along with decreasing relaxation time T-22 and a new relaxation time T-23 appeared at 50 degrees C, which indicated that partially immobilised water was converted into free water outside. Meanwhile, surface hydrophobicity increased significantly and free sulfhydryl contents decreased, which contributed to the formation of disulfide bonds, especially beyond 55 degrees C. Finally, the transformation of alpha-helix into beta-sheets occurred, and increasing beta-sheets are necessary for the formation of elastic gels. Moreover, there was a significant correlation between alpha-helical contents and water loss, surface hydrophobicity, sulfhydryl contents.