John Gernot T, Goelling Detlef, Klimant Ingo, Schneider Holger, Heinzle Elmar
Technische Biochemie, Saarland University, 66123 Saarbrücken, Germany.
J Dairy Res. 2003 Aug;70(3):327-33. doi: 10.1017/s0022029903006344.
A new method for characterization of acid production by dairy starter cultures is presented. Microplates with integrated optical pH sensors are developed. Two fluorophores, a pH-sensitive and a pH-insensitive one are immobilised at the bottom of a polystyrene 96-well microtitre plate. The pH-insensitive fluorophore serves as an internal reference and makes calibration unnecessary. The sensor measures pH accurately in optically well-defined media. Particles and fluorophores contained in the bulk medium disturbed the measurements. Despite these disturbances it was possible to clearly sense differences in inoculum type and in inoculum sizes of cultures of Lactococcus lactis and of Streptococcus thermophilus at 30 and 37 degrees C. Besides a pH-related signal there is information about other changes during milk fermentation. The cultivation results were compared with those from the established CINAC-method. From this comparison it can be concluded that the new method can be used reliably to characterize particularly a large number of strains for screening purposes but also for quality control.
本文介绍了一种用于表征乳制品发酵剂产酸特性的新方法。开发了带有集成光学pH传感器的微孔板。将两种荧光团，一种对pH敏感，另一种对pH不敏感，固定在聚苯乙烯96孔微量滴定板底部。对pH不敏感的荧光团用作内部参考，无需校准。该传感器能在光学定义良好的介质中准确测量pH值。大量培养基中含有的颗粒和荧光团会干扰测量。尽管存在这些干扰，但仍能清楚地检测到乳酸乳球菌和嗜热链球菌在30℃和37℃下接种物类型和接种量的差异。除了与pH相关的信号外，还有关于牛奶发酵过程中其他变化的信息。将培养结果与既定的CINAC方法的结果进行了比较。从该比较中可以得出结论，新方法可可靠地用于特别大量菌株的表征，用于筛选目的以及质量控制。
