School of Materials Science and Engineering, Qilu University of Technology, Jinan, 250353, PR China.
School of Materials Science and Engineering, Qilu University of Technology, Jinan, 250353, PR China.
Int J Biol Macromol. 2018 Feb;107(Pt A):1074-1079. doi: 10.1016/j.ijbiomac.2017.09.079. Epub 2017 Oct 7.
The influence of the concentration and type of salt on the physical gelation of gelatin at early stages was explored by polarimeter, rheometer and differential scanning calorimetry (DSC). With the increase of salt concentration, both the triple helix content and the storage modulus of gelatin increased slightly and then decreased in CaCl solutions, whereas they decreased monotonically in NaCl and CrCl solutions. The addition of CaCl at low concentrations facilitated the coil-helix transition of gelatin, which could be significantly inhibited by high salt concentrations. The melting temperature of gels was nearly unchanged with varying salt concentration, but the melting enthalpy decreased monotonically with salt addition. This result indicates that salt additions mainly affect the nucleation of triple helices, but had minor effect on its growth. In addition, the coil-helix transition of gelatin in salt solutions at early stages could be treated successfully by an equation of first order kinetics.
通过偏光显微镜、流变仪和差示扫描量热法（DSC）研究了盐的浓度和类型对明胶早期物理凝胶化的影响。随着盐浓度的增加，明胶的三螺旋含量和储能模量先略有增加，然后在 CaCl2 溶液中降低，而在 NaCl 和 CrCl3 溶液中则单调降低。低浓度 CaCl2 的添加促进了明胶的螺旋-卷曲转变，而高盐浓度会显著抑制这种转变。凝胶的熔点随盐浓度的变化几乎不变，但随着盐的加入，熔融焓单调下降。这一结果表明，盐的加入主要影响三螺旋的成核，但对其生长影响较小。此外，明胶在盐溶液早期的螺旋-卷曲转变可以用一级动力学方程成功描述。
