Non-destructive determination of components in processed cheese slice wrapped with a polyethylene film using near-infrared spectroscopy and chemometrics

This paper explored a novel non-destructive method for the determination of ingredients, fat, protein and sodium chloride (NaCl), in processed cheese slice wrapped with a polyethylene (PE) film by using near-infrared (NIR) diffuse reflectance spectroscopy. A simple mathematical way, partial least squares (PLS) regression combined with second-order derivative, is proposed for removing the contributions of PE film from NIR spectra. During the operating of this method, the peak separation was enhanced and the essential information directly related to the analytes was condensed. The result of second-order derivative pre-treatment indicates that it effectively removes the film's effect from NIR spectra of wrapped processed cheese samples, and the PLS regression for fat, protein and NaCl reveals that it enables the building of satisfactory calibration models for the ingredients in cheese slices even within PE film. The use of such analytical techniques potentially makes it possible to remove an intensity contribution from PE film simply in a mathematical way for easy-to-use high quality analytical methods in dairy industries.