College of Food Science, Southwest University, Chongqing 400715, China.
College of Food Science, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Speciality Food Co-Built by Sichuan and Chongqing, Chongqing 400715, China.
Food Chem. 2022 Nov 30;395:133578. doi: 10.1016/j.foodchem.2022.133578. Epub 2022 Jun 27.
In this work, the structure-property differences and mechanisms of gelatin induced by transglutaminase (TGase) covalent cross-linking were investigated. The results showed that higher hardness was obtained with a cross-linking degree of 13.55%, attributing to an active intra-molecular cross-linking and a tight network structure under a certain amount of triple helix-like structure. The inter-molecular cross-linking played a positive role in the transition from random coil to left-handed single helix chains, while triple helix-like structure could not been formed owing to the steric hindrance and hydrogen bond reduction, showing the decrease of hardness and increase of viscosity. Additionally, the ε-(γ-Glu)-Lys isopeptide bond significantly increased the initial degradation temperature. Macromolecular polymers with a cross-linking degree of 37.48% allowed sol state of gelatin gel could be maintained even heating at 100 ℃ for 10 min. This study might provide an innovative reference for the regulation and application of gelatin gel structure-properties.
在这项工作中，研究了转谷氨酰胺酶（TGase）共价交联诱导明胶的结构-性能差异和机制。结果表明，交联度为 13.55%时，硬度较高，这归因于一定量的三螺旋结构下，活性的分子内交联和紧密的网络结构。分子间交联对从无规卷曲到左手单链的转变起积极作用，而三螺旋结构由于空间位阻和氢键减少而无法形成，表现为硬度降低和粘度增加。此外，ε-（γ-谷氨酰基）-赖氨酸异肽键显著提高了初始降解温度。交联度为 37.48%的高分子聚合物使得明胶凝胶即使在 100℃加热 10 分钟也能保持溶胶状态。本研究可能为调控和应用明胶凝胶的结构-性能提供新的参考。
