食醋总酸近红外快速检测方法的研究

利用傅立叶变换近红外光谱技术结合偏最小二乘法（PLS）对食醋的总酸进行快速检测分析。随机采集106个不同酸度食醋的实验数据、扫描近红外光谱图，选择最优的光谱预处理方法优化、建立模型。利用模型对15个未参与建模的食醋样品总酸的含量进行预测，外部验证模型的准确性。结果表明，食醋总酸实测值与对应采集的近红外漫反射光谱相关联建立的快速检测模型，其近红外食醋总酸模型的交叉验证决定系数（R2）为0.972 3，交叉验证均方差（RMSECV）为0.062 1。经外部验证后，该模型食醋总酸预测值和实测值的绝对偏差平均值为0.035，最大相对误差为1.383%，两者间相关性系数为0.995。该方法可以快速、高效、简便地用于食醋总酸的快速检测。

Rapid detection method of total acid in vinegar by near infrared spectroscopy

The total acid content of vinegar was rapidly detected and analyzed by Fourier transform near infrared spectroscopy combined with partial least square(PLS)method.The acidity data of 106 vinegar samples and near-infrared spectrogram of the samples were randomly collected.The optimal spectral pretreatment method was selected to optimize and establish the model.The total acid content of 15 vinegar samples not involved in the modeling was predicted by the model,and the accuracy of the model was externally verified.The results showed that the model,which established combining the measured value of total acid in vinegar with the corresponding near-infrared diffuse reflectance spectrum,the cross-validation determination coefficient(R2)and root mean square error of cross validation(RMSECV)of the model were 0.9723 and 0.0621,respectively.After external verification,the absolute deviation of acidity between the predicted value of the model and the measured value was 0.035 on average,the maximum relative error was 1.383%,and the correlation coefficient was 0.995.The method could be used to detect the acidity of vinegar quickly,efficiently and simply.