Use of FTIR-ATR spectroscopy combined with multivariate analysis as a screening tool to identify adulterants in raw milk

Abstract

The objective of this study was to use Fourier transform infrared (FTIR) spectroscopy combined with multivariate analysis to identify adulterations in raw milk and in samples from producers. Five levels of concentration of sodium bicarbonate, sodium hydroxide, hydrogen peroxide, starch, sucrose and urea were used. A total of 620 samples previously adulterated, frozen and lyophilized were analyzed in FTIR-attenuated total reflection (ATR) equipment and 15 peaks of the spectra were obtained. With the multiple linear regression method for samples adulterated with sodium bicarbonate, sucrose and urea, a coefficient greater than 75% was obtained, and with artificial neural networks all adulterated samples obtained a percentage of correctness greater than 76.6%, making it possible to identify adulterants from 0.1%. Of the 249 samples of producers analyzed, 2.4% were adulterated. With the use of FTIR allied to the multivariate analysis as a screening method, it was possible to obtain a satisfactory classification for the adulterated samples in this study.