枣花及枣花蜜香气成分保留指数的神经网络法研究

Study on the Retention Index of Aroma Components of Jujube Flower and Jujube Honey with the Neural Network Method

为建构枣花和枣花蜜香气成分保留指数的神经网络的结构-性质关系模型,计算其连接性指数(mX)及电性距离矢量(Mi),选取连接性指数的0X,1X,2X,3X,5Xc,4Xpc和电性距离矢量的M14,M15,M21,M32共10种结构参数,作为BP神经网络方法的输入层变量,枣花成分的保留指数作为输出层变量,采用10-4-1的网络结构,构建模型总的相关系数R为0.988 6,根据模型计算得到的保留指数预测值与实验值的平均相对误差为2.34%;同理选取连接性指数的0X,1X,3X和电性距离矢量的M1,M2,M14,M15,M21,M32共9种参数,将它们与枣花蜜香气成分的保留指数进行神经网络法研究,采用9-4-1的网络结构,所得模型总相关系数R为0.992 3,保留指数预测值与实验值的平均相对误差为2.07%.结果表明,—C—、—C=、—C<、=C<或=O等基团片段是影响枣花或枣花蜜香气成分保留指数大小的主要因素.

In order to provide a theoretical basis for the development and application of jujube flower and jujube honey in the drug and food industries, the molecular connectivity indices(mX) and the electronegativity distance vectors(Mi) of aroma components of jujube flower and jujube honey were calculated to establish a neural network model of structure-property relationship for their chromatographic retention indices of aroma components. Ten configuration parameters, i.e. the connectivity indices 0X,1X,2X,3X,5Xc, and 4Xpc and the electronegativity-distance vectors M14,M15,M21 and M32, were selected, and were used as input layer variables and the retention index was used as the output layer variable. Besides, the 10-4-1 network structure was adopted and BP neural network method was used to establish a neural network model, whose total correlation coefficient R was 0.988 6. The mean relative error between the predicted values and the experimental values of retention index was 2.34%. Similarly, nine configuration parameters, i.e. the connectivity indices 0X,1X, and 3X and the electronegativity-distance vectors M1,M2,M14,M15,M21 and M32, were selected and used in the neural network study. The 9-4-1 network structure was adopted and BP neural network method was used to establish a model to study retention index of aroma components of jujube honey. The total correlation coefficient R of the model was 0.992 3. The mean relative error between the predicted values and the experimental values of retention index was 2.07%. The results showed that the —C—,—C=,—C<,=C< or =O iso-group fragments were the main factors affecting the retention index of aroma components of jujube flower or jujube honey.