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

Abstract

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.

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

“…Several approaches have recently been proposed based on the analysis of DNA by CE methods [62][63][64][65][66][67][68][69][70], these applications include e.g., the detection of food-borne pathogens, genetically modified organisms (GMOs) or the study of food authenticity. The majority of these studies were directed to increase throughput and reduce time of analysis.…”

“…The majority of these studies were directed to increase throughput and reduce time of analysis. Among the strategies explored to speed up the detection of amplified DNA sequences in foods are the use of multiplex polymerase chain reaction (PCR) combined with CGE-LIF [62], ligation-dependent probe amplification (LPA) with CGE-LIF [63] and microchip capillary electrophoresis [64][65][66]. The latter strategy will be discussed later in Microchip CE section.…”

“…These applications of microchips-CE include the analysis of DNA [64][65][66], proteins [110], amines [111], seleno-amino acids [112], antioxidants [113,114] and sulfite [115]. Besides, among the current developments in microchip-CE, different detection schemes have been developed to be used together with these microdevices.…”

DNA-Based Approaches for Traceability and Authentication of Olive Oil

“…Preliminary results exhibited eicient discrimination potential except for sesame and avocado [29]. This approach was successfully used in previous authentication studies for the analysis of cofee [81] and while it was further improved by using a DN" capillary electrophoresis platform [82]. "s a proof of concept, sesame oil could be easily discriminated from olive oil in a reliable way that was validated through a single-base primer extension assay [15].…”

Restriction Fragment Length Polymorphism Analysis of PCR-Amplified Fragments (PCR-RFLP) and Gel Electrophoresis - Valuable Tool for Genotyping and Genetic Fingerprinting

“…For example, this approach is useful in the quality control and regulatory screening in enforcement laboratories including screening to detect undeclared admixture of fish species in seafood products (Dooley et al, 2005). Lab-on-a-chip capillary electrophoresis of digested amplicons can also be applied for authentication of coffee beans (Spaniolas et al, 2006).…”