Chemometric Quantification of Peaberry Coffee in Blends Using UV-Visible Spectroscopy and Partial Least Squares Regression

The aim of the present study is to quantify peaberry coffee in blends using UV-visible spectroscopy and partial least squares (PLS) regression. A total of 210 ground roasted peaberry coffee in blends (pure and adulterated with degree of adulteration 0%-90%) were used as samples. After the extraction process, spectral data of 3 mL aqueous samples was acquired using a UV-visible spectrometer in the range of 190-1100 nm (Genesys 10s, Thermo Scientific, USA). The PLS regression was used to quantify the peaberry content in blends (peaberry-to-normal blends). The best PLS model was achieved using Savitzky-Golay first derivative spectra in the interval of 190-450 nm with low root mean square error of calibration (RMSEC = 1.165430%) and high determination coefficient (R-2 = 0.99). The calibration model also had high a RPD, 11.88. This analytical method is simple, easy to use, of low cost, and has excellent sensitivity.