Discrimination and classification of adulterants in maple syrup with the use of infrared spectroscopic techniques

Abstract

Food adulteration is a profit-making business for some unscrupulous manufacturers. Maple syrup is a soft target of adulterators owing to its simplicity of chemical composition. In this study the use of Fourier transform infrared (FTIR) spectroscopy and near-infrared (NIR) spectroscopy to detect adulterants such as cane and beet invert syrups as well as cane and beet sugar solutions in maple syrup was investigated. The FTIR spectrum of adulterated samples was characterised and the regions 800-1200 cm À1 (carbohydrates) and 1200-1800 and 2800-3200 cm À1 (carbohydrates, carboxylic acids and amino acids) were used for detection. The region between 1100 and 1660 nm in the NIR spectrum was used for analysis. Linear discriminant analysis (LDA) and canonical variate analysis (CVA) were used for discriminant analysis, while partial least squares (PLS) and principal component regression (PCR) were used for quantitative analysis. FTIR was more accurate in predicting adulteration using two different regions (R 2 > 0.93 and >0.98) compared with NIR (R 2 > 0.93). Classification and quantification of adulterants in maple syrup show that NIR and FTIR can be used for detecting adulterants such as pure beet and cane sugar solutions, but FTIR was superior to NIR in detecting invert syrups.

Mid-infrared spectrometry: A tool for the determination of chemical parameters in Emmental cheeses produced during winter

“…The region 1500-600 cm -1 , called the fingerprint region, refers to C-O and C-C stretching modes (1153-900 cm -1 ). Absorbance in the region 1474-1200 cm -1 is due to bending modes of O-C-H, C-C-H and C-O-H [30,37]. The strong absorption at 1470 cm -1 is assigned to the carboxylic acid group of lactic acid [12].…”

Fluorescence and infrared spectroscopies: a tool for the determination of the geographic origin of Emmental cheeses manufactured during summer

“…The absorption bands observed in the midinfrared (4000-900 cm -1 ) are mainly associated with fundamental valence vibrations of functional groups of the molecules. Most of the spectral information used for the discriminant analysis is located: (1) in the 3000-2800 cm -1 range corresponding to C-H stretching; (2) in the region located between 1700-1500 cm -1 corresponding to the amide I and II; and (3) in the 1500-900 cm -1 region called the fingerprint region [21].…”

Detection of Butter Adulteration with Lard by Employing ¹H-NMR Spectroscopy and Multivariate Data Analysis

“…3.2 Quantification of lard in butter using 1 H-NMR spectroscopy and PLS Partial Least Square PLS 29 is a versatile tool with many desirable properties, i it is able to cope with highly collinear and low rank data, which is not the case of multiple linear regression 30 ; PLS allows analysing data with more variables than observations; ii PLS provides models with high stability of predictions because the risk of overfitting is minimised; iii PLS is very efficient in handling missing data and therefore it provides inferential models extremely robust to sensor failure and iv with the aid of careful data analysis and easy-to-use charts, PLS is able to detect outliers, which improves the quality of the fitted models and reduces the risk of extrapolation when new observations are projected over the model. Quantification of lard in butter was performed using multivariate calibration of PLS model.…”