Near infrared spectroscopy in combination with a transflection probe was investigated as inline measurement in a continuous flash pasteurizer system with a sugar-water model solution. Robustness and reproducibility of fluctuations of recorded spectra as well as trueness of the chemometric analysis were compared under different process parameter settings. Variable parameters were the flow rate (from laminar flow at 30 L/h to turbulent flow at 90 L/h), temperature (20 to 100 °C) and the path length of the transflection probe (2 and 4 mm) while the pressure was kept constant at 2.5 bar. Temperature and path length were identified as the most affecting parameters, in case of homogenous test medium. In case of particle containing systems, the flow rate could have an impact as well. However, the application of a PLS model, which includes a broad temperature range, and the correction of prediction results by applying a polynomial regression function for prediction errors, was able to compensate these effects. Also, a path length of 2 mm leads to a higher accuracy. The applied strategy shows that by the identification of relevant process parameters and settings as well as the establishment of a compensation strategy, near infrared spectroscopy is a powerful process analytical tool for continuous flash pasteurization systems.

中文翻译：

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基于模型的透反射近红外光谱优化作为连续闪蒸巴氏灭菌器中的过程分析工具

近红外光谱与透反射探头结合作为在线测量进行了研究，该方法在具有糖水模型溶液的连续快速巴氏杀菌系统中进行。在不同的工艺参数设置下比较了记录光谱波动的稳健性和再现性以及化学计量分析的真实性。可变参数是流速（从 30 L/h 的层流到 90 L/h 的湍流）、温度（20 到 100 °C）和透反射探头的路径长度（2 和 4 mm），而压力保持恒定在 2.5 bar。在均质测试介质的情况下，温度和路径长度被确定为影响最大的参数。在含颗粒系统的情况下，流速也会产生影响。然而，PLS模型的应用，它包括广泛的温度范围，并且通过应用多项式回归函数来修正预测误差，能够补偿这些影响。此外，2 毫米的路径长度导致更高的精度。应用策略表明，通过确定相关工艺参数和设置以及建立补偿策略，近红外光谱是连续快速巴氏杀菌系统的强大过程分析工具。