The near-infrared optic probe for monitoring rennet coagulation in cow's milk

A near-infrared (NIR) reflectance optic probe and a coagulometer (thermal p robe) were used for monitoring rennet coagulation of milk from individual c ows. Completed near-infrared spectral information (1100-2500 nm) was regist ered at 2 min intervals for up to 50 min after renneting, which led to a po ol of 1300 spectra. The data were analyzed by partial least squares (PLS) a nd after application of the second derivative, the standard error of calibr ation and the correlation coefficient were 0.20 and 0.94. The standard erro r of prediction was 0.36 with a correlation coefficient of 0.87. The study shows that NIR reflectance is a reliable method for monitoring milk coagula tion. Furthermore, NIR technology provides a better estimate of the coagula tion profile than the coagulometer (thermal probe). (C) 1998 Elsevier Scien ce Ltd. All rights reserved.