环糊精对к-卡拉胶热可逆凝胶过程影响及流变特性调控

As for cyclodextrin including its inclusion complex and carrageenan have been widely used in food industry, less investigate was take care of the interactions relationship between the two. Applicants have found that the hardness and elasticity of κ-carrageenan thermal reversible gel was significantly influenced by the addition of cyclodextrins. However, the related mechanism is not clear. In this project, we will firstly select typical cyclodextrin molecules, prepare κ-carrageenan–cyclodextrin–water ternary gel system. The structure of the gel will be characterized by FTIR, SEM, X-ray diffraction and NMR, etc. The effect of cyclodextrins which have different structures and curve sizes on the gel characteristic of κ-carrageenan will be investigated by rheological analysis, texture analysis and TG/DTA technique. After that, the method of structure-activity analysis and quantum chemistry will be employed to reveal the gelation mechanism between cyclodextrin and κ-carrageenan, construct the gel structure model, and understand the regulatory mechanism of the gel characteristic. Based on the above analysis, the controlled-release model of cycldextrin supramolecular inclusion complex in the gel system will be built based on the theory of supramolecular theory of host-guest chemistry and stability constant analysis to reveal the action mechanism of the ternary gel system. The obtained results will enrich the theory of κ-carrageenan gel system and prompt the application of κ-carrageenan in functional food industry.

环糊精和卡拉胶在食品工业中有广泛的应用，但二者的相互作用关系还没有研究者进行深入探讨。申请人在前期研究中发现，环糊精对κ-卡拉胶热可逆凝胶的硬度和弹性产生明显影响，而相关机作用制尚不明确。因此本项目拟首先选取典型环糊精分子，制备不同κ-卡拉胶−环糊精−水三元凝胶体系，通过红外、电镜扫描、X-衍射、核磁等技术对凝胶结构进行表征，借助流变、质构分析和热重/差热技术研究不同结构及孔径的环糊精对κ-卡拉胶凝胶特性的影响；然后引入构效分析和量子化学方法，揭示环糊精与κ-卡拉胶间的凝胶机理，构建凝胶结构模型，明确体系的胶凝特性调控机制；在此基础上，利用主客体化学超分子理论和稳定常数分析进一步构建环糊精超分子包合物在凝胶体系中的释放规律模型，揭示该三元凝胶体系的作用机理。本项目对于丰富现有的κ-卡拉胶凝胶体系理论，促进κ-卡拉胶在功能性食品中的应用具有重要的意义。

κ-卡拉胶是食品工业中常用的制备食用凝胶的原料，但κ-卡拉胶凝胶存在脆性大、易泌水、冻融稳定性差等问题。前期研究发现，环糊精对κ-卡拉胶热可逆凝胶的硬度和弹性产生明显影响，而相关机作用制尚不明确。因此本项目首先选取了5种典型环糊精分子，制备了不同环糊精/κ-卡拉胶/水三元凝胶体系，对体系物性和稳定性进行考察，引入构效分析和量子化学方法揭示环糊精对κ-卡拉胶凝胶影响机理，并进一步考察了其应用效果。环糊精对κ-卡拉胶凝胶的质构特性有明显影响。环糊精对κ-卡拉胶的凝胶温度有提升作用，而使其表观黏度降低。冻融稳定性试验结果表明，κ-卡拉胶/环糊精/水三元凝胶析水率比单纯κ-卡拉胶凝胶的析水率降低。热重试验结果表明，环糊精使κ-卡拉胶凝胶体系的热稳定性显著提高，分解温度提高50℃以上。扫描电镜图片显示，环糊精加入后凝胶壁层变得光滑，三维网络结构也更加细密。红外光谱和核磁氢谱表明，κ-卡拉胶和环糊精分子间存在明显的氢键相互作用。分子模拟计算也验证了这一结果。环糊精对κ-卡拉胶相凝胶特性的影响机理主要为（1）在溶胶状态下，环糊精可促进κ-卡拉胶的定向重排，在此过程中氢键起到重要作用，较弱的分子间氢键有利于环糊精发挥促进卡拉胶有规律重排的效果。（2）在凝胶化过程中，多糖中环糊精的存在阻止了网状结构中长距离壁面的形成，从而形成孔洞更小的细腻三维网络结构。（3）凝胶形成后，环糊精附着在多糖表面及网络孔洞中，增加了凝胶网络的强度和持水性。总体上，环糊精使κ-卡拉胶物性和稳定性增强，泌水现象减少，环糊精衍生物的效果好于母体环糊精，环糊精添加量为1.5%时综合效果最优。环糊精对κ-卡拉胶/魔芋葡甘聚糖复配凝胶有类似影响。肉桂精油/环糊精包合物在κ-卡拉胶凝胶中有缓释性，应用于切片面包的防腐起到了较好效果。本项目对于丰富现有的κ-卡拉胶凝胶体系理论，促进κ-卡拉胶在功能性食品中的应用具有重要的意义。