Discrimination between roasted coffee, roasted corn and coffee husks by Diffuse Reflectance Infrared Fourier Transform Spectroscopy

Abstract

a b s t r a c tCoffee has been the target of fraudulent admixtures with cheaper materials, including coffee husks and other roasted grains. Given the successful application of spectroscopic methods in the field of food adulteration as fast and reliable routine techniques, the objective of this work was to evaluate the feasibility of employing Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) for discrimination between roasted coffee and common adulterants (roasted corn and coffee husks). Arabica coffee beans, coffee husks and ground corn kernels were submitted to light, medium and dark roasts at temperatures ranging from 200 to 260 C. Principal Components Analysis of the DRIFTS spectra provided separation of the samples into three groups: coffee, coffee husks and corn. Classification models were developed based on Linear Discriminant Analysis, and such models provided complete discrimination (100% recognition and prediction) between roasted coffee, pure adulterants (corn and coffee husks) and adulterated coffee samples. Such results indicate that DRIFTS can be employed for discrimination between coffee and its common adulterants.

Characterization of Alkaline Treatment and Fiber Content on the Physical, Thermal, and Mechanical Properties of Ground Coffee Waste/Oxobiodegradable HDPE Biocomposites

“…Two peaks of 2859 and 2923 cm −1 represented the existence of the methyl and methylene group that was attributed to asymmetric and symmetric stretching of C-H bonds in aliphatic chains. These peaks have been previously identified in roasted Arabica and Robusta coffee [25] and roasted coffee husks [26] and attributed to the presence of caffeine [27,28]. The same peaks have been recognized as the presence of the lipids in corn and corn flour sample [29].…”

Effect of Home Grinding on Properties of Brewed Coffee

“…Using FTIR is not uncommon in published studies of coffee (Karoui et al, 2010;Paradkar & Irudayaraj, 2002;Reis et al, 2013;Singh et al, 1998). Since ATR-FTIR involves no separation of the coffee components (as takes place in any chromatography-based technique), a particular region of spectra may be influenced by the presence of more than one coffee component.…”

Identification of Meat Species by Using Molecular and Spectroscopic Techniques

“…These methods are generally based on transmittance or reflectance readings, and they require none or very little sample pretreatment (Reis et al, 2013). Infrared (IR) spectroscopy as a well accepted analytical technique because it is environment-friendly and does not need complicated sample preparation procedure (Al-Jowder et al, 1997;Hashim et al, 2010;Liu et al, 2012;Liu et al, 2013).…”