原花青素诱导明胶水凝胶的形成与稳定

Formation and Stability of Gelatin Hydrogel induced by Procyanidins

通过研究缩合类植物单宁——原花青素与明胶在亚浓溶液状态下的相互作用,探讨原花青素诱导的明胶水凝胶的形成及其稳定性。实验表明,低浓度的原花青素有助于明胶凝胶的形成;当原花青素与明胶质量比适当时,比如1:10,混合液在接近0℃冷冻后能形成具有多分枝网状结构的水凝胶,但在室温下则恢复成均匀液体,表明该凝胶体系对温度敏感,稳定性较差,原花青素-明胶之间的结合力较弱。高浓度的原花青素与明胶形成沉淀,FTIR图谱显示二者之间有氢键的形成;从DSC图谱上看,原花青素-明胶沉淀的热稳定性较明胶大大提高。低浓度的中性盐(NaCl)溶液能促进明胶凝胶的形成,但高浓度的NaCl则破坏了原花青素-明胶凝胶的形成。

The interaction between the procyanidins （PC） and gelatin in the semidilute solution was investigated experimentally, aiming to explore the formation and stabilization of Gelatin hydrogels induced by PC. It shows that the addition of PC at low-concentration will induce gelation solution to form hydrogels before gelation point of gelatin at 0 ℃. When at suitable mass ratios, such as Gelatin / PC= 10 / 1, the PC-gelatin solution may form the hydrogels in which the tan branch-like structures appear after frozen at slightly below 0℃. However, the hydrogel with branch-like structure inside will return to mixed solutions state at room temperature, which indicates that this hydrogel is sensitive to increasing temperature and has low stability due to the weak interactions between PC and gelatin at present study conditions. The precipitates will form when PC of high-concentration mixed with gelatin, and hydrogen bond shows to be existed between gelatin and PC in their coagulation by Fourier Transform Infrared Spectroscopy （FTIR）. The results of Differential Scanning Calorimetry （DSC） show that the thermal stability of Gelatin/PC aggregates have a greater improvement than pure gelatin. Besides, the gelation-points of gelatin will drop effected by the addition of neutral salt （NaCl） of Low-concentrations, while NaCl solution of high-concentration will prevent Gelatin/PC from forming hydrogels in our study.