Detection of adulterations in processed coffee with cereals and coffee husks using capillary zone electrophoresis

Abstract

The proposed method for the identification of adulteration was based on the controlled acid hydrolysis of xylan and starch present in some vegetable adulterants, followed by the analysis of the resulting xylose and glucose, which are the monosaccharides that compose, respectively, the two polysaccharides. The acid hydrolysis with HCl increases the ionic strength of the sample, which impairs the electrophoretic separation. Thus, a neutralization step based on anion exchange resin was necessary. The best separations were obtained in NaOH 80 mmol/L, CTAB 0.5 mmol/L, and methanol 30% v/v. Because of the high value of pH, monosaccharides are separated as anionic species in such running electrolyte. The LOQ for both monosaccharides was 0.2 g for 100 g of dry matter, which conforms to the tolerable limits.

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

“…Other detection modes such as capacitively coupled contactless conductivity (C 4 D) or AD have also been used for the analysis of carbohydrates by CE 80, 81. Thus, a CZE‐C 4 D method has been described for the detection of adulterations in instant coffee by the addition of coffee husks and corn by Nogueira and Lago 80. In that work, xylose and glucose, which were obtained by acid hydrolysis of xylan and starch, respectively, present in the adulterants, were used as the quality markers.…”

“…Peak identification: xy, xylose; fr, fructose; ma: mannose; ar, arabinose; gl, glucose; ga, galactose. Redrawn from 80 with permission from Wiley‐VCH.…”

Authenticity of Caffeine Containing Beverages

“…More recently a capillary zone electrophoresis method has been employed for the same purpose (40). There is a typical carbohydrate pattern in coffee.…”

Identification and Quantification of Adulterants in Coffee (Coffea arabica L.) Using FT-MIR Spectroscopy Coupled with Chemometrics

“…With the considerable increase in the coffee industry, it is necessary to develop techniques to identify the adulterants in the product [ 4 ]. Several analytical techniques to identify and quantify adulterants in coffee have been developed, for example, anion exchange chromatography [ 7 ], capillary electrophoresis [ 8 ], near infrared Fourier transform spectroscopy (FT-NIR) [ 9 ], high-performance liquid chromatography (HPLC) [ 10 ] and UV-vis spectroscopy [ 11 ]. Although these techniques are sensitive and precise, they can be performed only by trained personnel, and the sample preparation time may be extremely large.…”