Analysis of proteins in bovine milk is usually tackled by time-consuming analytical approaches involving wet-chemical, multi-step sample clean-up procedures. The use of external cavity-quantum cascade laser (EC-QCL) based IR spectroscopy was evaluated as an alternative screening tool for direct and simultaneous quantification of individual proteins (i.e. casein and β-lactoglobulin) and total protein content in commercial bovine milk samples. Mid-IR spectra of protein standard mixtures were used for building partial least squares (PLS) regression models. A sample set comprising different milk types (pasteurized; differently processed extended shelf life, ESL; ultra-high temperature, UHT) was analysed and results were compared to reference methods. Concentration values of the QCL-IR spectroscopy approach obtained within several minutes are in good agreement with reference methods involving multiple sample preparation steps. The potential application as a fast screening method for estimating the heat load applied to liquid milk is demonstrated.

牛乳中蛋白质的分析通常通过耗时的分析方法来解决，该方法涉及湿化学法，多步骤样品净化程序。已评估使用基于外腔量子级联激光（EC-QCL）的红外光谱作为直接和同时定量市售牛乳样品中单个蛋白质（即酪蛋白和β-乳球蛋白）和总蛋白质含量的替代筛选工具。蛋白质标准混合物的中红外光谱用于建立偏最小二乘（PLS）回归模型。分析了包含不同类型牛奶（巴氏杀菌；经过不同处理的延长的货架期，ESL；超高温，UHT）的样品集，并将结果与​​参考方法进行了比较。几分钟内获得的QCL-IR光谱方法的浓度值与涉及多个样品制备步骤的参考方法非常吻合。演示了一种潜在的应用，它是一种快速筛选方法，用于估算施加到液态奶上的热负荷。