Analysis of adulteration in honey with standard sugar solutions and syrups using attenuated total reflectance-Fourier transform infrared spectroscopy and multivariate methods

Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and multivariate analysis were used to study honey intentionally adulterated with standard sugar solutions (glucose, fructose and sucrose), and also with cheap syrups (corn, inverted and cane sugar). By using the principal component analysis (PCA) method on pure and adulterated (0-100%) honey samples, the determination of the type of adulterant was realized in an easy way through the use of the two- and three-dimensional PCA score plots. From this analysis, a tetrahedral structure was obtained. Superior vertex is formed by the set of samples of pure honey, whereas the edges are formed by the adulterant sugars. Partial least squares method was employed to develop optimal calibrations for the six adulterants used, obtaining values of standard error of calibration in the range 0.377-0.583 and standard error of prediction in the range of 1.550-3.150 for the standard sugars, which suggest a good predictive capacity of the model employed in this study.