紫外-可见光谱法定量检测牛奶菌群总数的研究

针对平板计数、ATP生物发光等传统牛奶菌群总数检测方法耗时长,现有光谱技术操作复杂等问题,将紫外-可见光谱法结合化学计量学应用于牛奶中菌群总数的定量分析,并采用优化的偏最小二乘法建立牛奶菌群总数的定量模型。以等时间段(0,2,4,…,20 h)32℃恒温下培养的牛奶为研究对象,探究光谱与牛奶菌群总数之间的定量关系。采用连续投影算法选出19个特征波数;再利用偏最小二乘模型建立基于特征波与菌群总数的模型关系;优化后的模型具有更高的相关系数(Rp优=0.978,Rp原=0.968)和更小的均方根误差(RMSE优=0.265,RMSE原=0.324)。该研究采用紫外-可见光谱检测细菌总数的方法为快速检测牛奶菌群数量提供了新思路。

Rapid Determination of Milk Bacteria by UV-Vis Spectroscopy

To solve the time-consuming problem of traditional detective methods,such as total viable counts and ATP bioluminescence technique,and the complicated operations of the existing spectrum techniques,a method for the quantitative analysis of the total number of bacteria in milk by UV Vis spectroscopy combined with chemometrics,followed by application of the optimized partial least squares to set up the model of the total amount of milk bacteria.With the milk cultured in the same time period(0,2,4,…,20 h) as target,the quantitative relationship between the spectrum and the total number of milk bacteria was explored.The successive projections algorithm was applied to select 19 characteristic waves,and then the partial least squares model was used to establish the model relationship between the characteristic waves and the total number of milk flora.The correlation coefficient R of 0.978 in the optimized model was higher than that of 0.968 in primitive model,and the root mean square error(RMSE) of 0.265 in the optimized model was lower than that of 0.324 in the primitive model.The proposed method provided a new idea and direction for the rapid detection of the number of milk flora.