Separation of arabic (Coffea arabica) and robusta (Coffea canephora) type coffee using the electronic nose

Electronic nose is a system used in many fields such as food, medicine, automotive and cosmetics consisting of sensor unit, electronic unit, and pattern recognition unit. Continuous advancing technology has enabled the development of fast methods such as electronic nose. Coffee is one of the most preferred beverages in the world. Coffee quality is generally determined by sensory analysis and chemical analysis. Studies have also been conducted with electronic nose systems on the determination of coffee quality. Coffee quality varies according to many factors, and the use of lower-cost coffees reduces the coffee quality and is considered fraudulent. With this study, Robusta coffee with lower quality at 0, 25, 50, 75 and 100% was added to Arabica coffee with the aim of cheating. The aroma components of the coffees were determined by integrating the solid phase micro-extraction method into gas chromatography. As a result of the analysis, it was observed that the aroma components of the alcohol, acid and aldehyde groups were predominant in the coffee. An electronic nose assembly was designed using MQ sensors and relevant samples were analyzed. The obtained signal data were processed with an arduino card and transferred to the program in computer environment. Classification percentages were determined by applying Linear separation analysis (LDA), Bayesian, nearest neighbor (kNN-3, kNN-5, kNN-7, and kNN-9), decision tree, oneR and support vector analysis (SVM) algorithm analysis to the obtained data. In the five-tier classifications, it was found that the maximum classification with 60.75% belongs to the MQ8 sensor in the decision tree algorithm. In the dual classification of 100% Arabica and 100% Robusta coffees, it was determined that the maximum rate belongs to the MQ7 sensor with 80.92%. With the work carried out, it was concluded that cheating in coffee could be determined at a certain level successfully with a lower cost and a faster method.