Authentication of Coffee by Means of PCR-RFLP Analysis and Lab-on-a-Chip Capillary Electrophoresis

• Published in: Journal of agricultural and food chemistry Vol. 54; no. 20; pp. 7466 - 7470
• Main Authors: Spaniolas, Stelios, May, Sean T, Bennett, Malcolm J, Tucker, Gregory A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 04-10-2006
• Subjects: Biological and medical sciences; capillary electrophoresis; chloroplast DNA; Chloroplasts - genetics; Coffea arabica; Coffea canephora; Coffee - classification; Coffee - genetics; coffee beans; Coffee, tea and other stimulative beverage industries; DNA, Plant - analysis; Electrophoresis, Capillary; Food Contamination - analysis; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; lab-on-a-chip capillary electrophoresis; Methods of analysis, processing and quality control, regulation, standards; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Polymorphism, Single Nucleotide; product authenticity; product certification; restriction fragment length polymorphism; single nucleotide polymorphism; Capillary electrophoresis; lab-on-a-chip; chloroplasts; PCR-RFLP; Coffee; Polymerase chain reaction; Coffee authentication; SNP; food forensics; Authentication; Quality control; Molecular biology; Chloroplast; Food
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf061164n

Coffee is one of the most important world food commodities, commercial trade consisting almost entirely of Arabica and Robusta varieties. The former is considered to be of superior quality and thus attracts a premium price. Methods to differentiate these coffee species could prove to be beneficial for the detection of either deliberate or accidental adulteration. This study describes a molecular genetics approach to differentiate Arabica and Robusta coffee beans. This employs a Polymerase Chain Reaction−Restriction Fragment Length Polymorphism to monitor a single nucleotide polymorphism within the chloroplastic genome. Samples were analyzed with a lab-on-a-chip capillary electrophoresis system. Coffee powder mixtures were analyzed with this technique, displaying a 5% limit of detection. The plastid copy number was found to be relatively constant across a wide range of bean samples, suggesting that this methodology can also be employed for the quantification of any adulteration of Arabica with Robusta beans. Keywords: Coffee authentication; food forensics; SNP; PCR-RFLP; lab-on-a-chip; chloroplasts