Chemometric quantification of peaberry coffee in blends using UV–visible spectroscopy and partial least squares regression

Abstract

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 (R2 = 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.