FT-IR SPECTROSCOPY CHARACTERIZATION AND CHEMOMETRIC EVALUATION OF LEGUMES EXTRACTED WITH DIFFERENT SOLVENTS

In this study, FT-IR spectroscopy was applied for rapid characterization and discrimination of commonly consumed legumes extracted by different solvents in combination with principal component analysis (PCA) for the first time. Dried soy bean, white bean, chickpea, red lentil, and pinto bean were extracted by water (W), ethanol (E), acetone/water (AW) and acetone/water/acetic acid (AA). The effect of each solvent on different legume extracts was demonstrated by identifying the functional groups using FT-IR spectroscopy at mid-infrared (mid-IR) range (4000-650 cm -1 ) and associated with the amount of total phenolics and other oxidation substrates in the extracts determined by Folin-Ciocalteu method. PCA models with 2 principal components were constructed to discriminate the different legume extracts based on FT-IR spectra and total phenolic content (TPC). FT-IR spectra of each legume were quite different for different solvents but almost the same for the same solvent. Each legume extracts had significantly different TPC from each other extracted with the same or different solvents. The highest TPC was obtained by soybeans and pinto beans extracted with W or E and AW or AA, respectively. PCA analysis of FT-IR spectra and TPC provided clear discrimination between the legume samples extracted with different solvents.