Detection of roasted and ground coffee adulteration by HPLC by amperometric and by post-column derivatization UV–Vis detection

Abstract

Coffee is one of the most consumed beverages in the world. Due to its commercial importance, the detection of impurities and foreign matters has been a constant concern in fraud verification, especially because it is difficult to percept adulterations with the naked eye in samples of roasted and ground coffee. In Brazil, the most common additions are roasted materials, such as husks, sticks, corn, wheat middling, soybean, and more recently - acai palm seeds. The performance and correlation of two chromatographic methods, HPLC-HPAEC-PAD and post-column derivatization HPLC-UV-Vis, were compared for carbohydrate analysis in coffee samples. To verify the correlation between the two methods, the principal component analysis for the same mix of triticale and acai seeds in different proportions with coffee was employed. The performance for detecting adulterations in roasted and ground coffee of the two methods was compared.

Analytical method to detect adulteration of ground roasted coffee

“…In another study, near‐infrared spectroscopy was successfully applied for identification and quantification of the fraudulent addition of barley in roasted and ground coffee samples (Ebrahimi‐Najafabadi et al ., ). Common methods used for the determination of coffee adulteration include high‐performance liquid chromatography (HPLC) with fluorescence detection, ultraviolet adsorption (UV), diode array detection and mass spectrometry (Ebrahimi‐Najafabadi et al ., ; Domingues et al ., ; Cai et al ., ).…”

“…Coffee is one of the most popular beverages, and its consumption has increased rapidly. However, a shortage of coffee beans has given rise to mixing pure ground coffee with coffee adulteration materials, such as spent coffee grounds, coffee berry skin, roasted barley, corn, seeds, twigs and other grains (Jham et al ., ; Oliveira et al ., ; Domingues et al ., ; Pauli et al ., ; Thorburn Burns et al ., ). Coffee was reported to be one of the top ten products having a risk of food fraud in the United States Pharmacopeia (USP) Convention (Database, ).…”

“…There are many kinds of chemical indices to detect adulteration of coffee, such as monosaccharides, amino acids, lipids and bioactive (Jham et al ., ; Oliveira et al ., ; Domingues et al ., ; Pauli et al ., ) Trigonelline, one of the chemical indices, exists specifically in coffee as a bioactive substance. During the roasting process, trigonelline suffers thermal degradation, generating a series of volatile compounds (Trugo & Macrae, ).…”

Luwak Coffee Classification Using UV-Vis Spectroscopy Data: Comparison of Linear Discriminant Analysis and Support Vector Machine Methods

“…Several studies have reported the development of reliable and specific coffee authentication methods. Near infrared (NIR) spectroscopy, mid infrared spectroscopy, gas chromatography-mass spectrometry and high performance liquid chromatography (HPLC) have been used for quality control, classification and authentication of coffee samples (Briandet et al, 1996;Domingues et al, 2014;Pizarro et al, 2007;Tavares et al, 2012). However, most of these instrumental techniques require harmful reagents and/or expensive equipment with large operational/maintenance costs (Souto et al, 2015;Souto et al, 2010).…”

New Method for Carbohydrates Determination in Sugarcane Bagasse by HPAEC‐RPAD Using Glassy Carbon Electrode Modified with Carbon Nanotubes and Nickel Nanoparticles

“…HPLC and HPAEC coupled with RID , pulsed amperometric detector (PAD) and reverse pulsed amperometric detection (RPAD) have been successfully applied towards the determination of carbohydrates in different matrices as they entail direct quantification without the need for carbohydrates derivatization, are deemed relatively economical and straightforward with regard to the quantification of these compounds. In addition to the methods described in the literature, there are also application notes of equipment manufacturers and chromatographic columns for sugar analysis in biomass .…”