发酵乳酸度近红外光谱快速检测方法的研究

利用近红外光谱技术对发酵乳酸度进行快速分析检测。采用电位滴定仪法测定71批次含活乳酸菌发酵乳样品的酸度实测值，并同时扫描得到近红外光谱数据。以校正集均方根误差(RMSEC)、预测集均方根误差(RMSEP)、交互验证均方根误差(RMSECV)及其相关系数R_c、R_p、R_cv为评价指标建立最优的酸度定量模型。利用模型对10批次含活乳酸菌发酵乳样品的酸度进行预测。结果表明，优化后的模型，其RMSEC、RMSEP、RMSECV及其相关系数R_c、R_p、R_cv分别为3.27、4.39、4.84,0.946 2、0.922 5、0.877 8。经外部验证后，该模型酸度预测值和实测值的最大相对误差为6.76%，满足不超过10%的要求。说明模型具有良好的预测性能，可用于发酵乳中酸度的快速检测。

Rapid determination method of acidity of fermented milk by near-infrared spectroscopy

Acidity of fermented milk was rapidly analyzed and detected by near infrared spectroscopy technology. The acidity measured value of 71 batches of fermented milk samples containing live lactic acid bacteria was determined by potentiometric titration method, and near infrared spectral data was obtained by scanning at the same time. The optimal acidity quantitative model was established with root mean square error of calibration (RMSEC), root mean square error of prediction (RMSEP), root mean square error of cross validation (RMSECV) and their correlation coefficients Rc, Rp, and Rcv as evaluation indexes, and the acidity of 10 batches of fermented milk samples containing live lactic acid bacteria was predicted by the model. The results showed that RMSEC, RMSEP, RMSECV and their correlation coefficients Rc, Rp, and Rcv were 3.27, 4.39, 4.84 and 0.946 2, 0.922 5, 0.877 8, respectively. After external validation, the maximum relative error between the predicted and measured values of the acidity with the model was 6.76%, meeting the requirement of less than 10%. These results indicated that the model had good predictive performance and could be used for the rapid detection of acidity in fermented milk.