摘要：食用香精对于食品风味提升起到了关键作用，而这其中定香剂对香味的维持至关重要，如何筛选出高留香时间的定香剂成为了一个问题。本文利用计算机手段在密度泛函理论的基础上，使用Gaussian软件进行量子化学计算。使用多元逐步线性回归法建立各类理化参数-定香剂留香时间的QSAR模型。并用拟合度以及残差大小评估该模型。最后的实验结果表明:最高最低轨道能极差△E的2.5次方、摩尔质量MW、密度、折光率MR这四个化合物属性影响这定香剂的留香时间。并根据最终模型的拟合度R2=0.649可以得出结论，本次实验所建立的的QSAR方程对于定香剂留香时间具有一定的预测能力。并在此QSAR模型的基础上设计了高留香时间的食用香精中的定香剂化合物。
关键词：食用香精；密度泛函理论；定量构效关系；定香剂；留香时间
Screening and Design of Fixative in Food Flavor
Abstract: Food flavor enhancement plays a key role in food flavor enhancement, and the retention of flavoring agent is crucial to the maintenance of aroma, and how to select the deodorant with high retention time becomes a problem. Based on density functional theory, Gaussian software is used to calculate quantum chemistry. The QSAR model of various physicochemical parameters - deodorant retention time was established by multivariate stepwise linear regression. The model was evaluated by fitting degree and residuals. The results of the experiment show that the highest minimum orbit can affect the time of retention of the flavoring agent by the properties of the four compounds: E to the 2.5 power, the molar mass MW, the density, and the refractive index. According to the final model's fitting R2=0.649, it can be concluded that the QSAR equation established in this experiment has certain predictive power for the retention time of the flavoring agent. On the basis of the QSAR model, the flavoring agent compounds in the edible essence of high retention time were designed.
Key Words： food flavor；DFT；QSAR；fixative；fragrance time
目录
1绪论1
1.1研究背景和目的...1
1.1.1食用香精的概述...1
1.1.2食用香精和定香剂的发展情况...1
1.1.3定香剂的综述.1
1.2研究进展.2
1.2.1定香剂的作用原理.2
1.2.2定香剂性能的衡量.2
1.2.3定香时间的确定...2
1.2.3.1失重法.2
1.2.3.2嗅辨法.3
1.2.3.3气相色谱质谱联用法.3
1.2.4定香时间与分子结构的关系.3
1.2.5现阶段的局限性...3
1.3QSAR简介3
1.4研究目的及意义...4
1.5课题主要研究手段.5
1.5.1食用香精中定香剂的几何构型的优化和参数的计算.5
1.5.2食用香精中定香剂化合物参数的整理.5
1.5.3食用香精中定香剂化合物分子结构参数与留香时间.5
2理论原理和计算方法..6
2.1理论基础.6
2.1.1密度泛函理论（DFT）..7
2.1.2选择合适的基组...7
2.1.3计算工具.7
2.2QSAR中常用的数理统计方法.8
2.2.1多元线性回归法...8
2.2.2多元线性回归验证方法.8
2.2.3所建模型的检验...9
2.2.4多元逐步回归法（Stepwise法）.9
2.3研究方法采取的研究方法及路线10
3QSAR模型的建立与检验...11
3.1研究对象11
3.2量子化学研究方法16
3.3实验数据来源17
3.4QSAR方程的初步建立与检验...17
3.4.1量子化学参数初步整理18
3.4.2相关性分析..19
3.4.3QSAR模型初步建立结果与模型检验..20
3.5QSAR方程的进一步建立与检验..21
3.5.1量子化学及理化参数再次整理..21 食用香精中定香剂的筛选与设计:http://www.chuibin.com/huaxue/lunwen_205110.html