A rapid Fourier transform infrared quality control method for the determination of lactose, sucrose, fat and total solids in chocolate milk

摘要

A Fourier transform infrared spectrometer was modified for the routine analysis of chocolate milk for fat, sucrose, lactose and total solids using an automated heated flow cell accessory equipped with a 50-mum transmission cell with CaF2 windows. Homogenized chocolate milk samples were centrifuged at 1200 x g for 3 min and preheated to 40 degreesC prior to analysis. A partial least squares calibration model was developed using 18 chemically pre-analyzed chocolate milk samples as standards, and the performance of the calibration was assessed by validating with production samples which were subsequently analyzed by chemical and chromatographic reference methods. The overall accuracy of the Fourier transform infrared predictions of the validation samples was +/-0.10%. The automated and programmed version of the method allowed the analysis of the centrifuged samples at a rate of one sample every two minutes, making it suitable for rapid atline process control of chocolate milk during production.