QCM sensor with polystyrene coating as a candidate for coffee aroma sensor

The Quartz Crystal Microbalance (QCM) chemical sensor is developed by coating the QCM sensor surface with a sensitive layer. QCM chemical sensor has been used to detect odors from agricultural products, breath, aromatic compounds, and many gases. The QCM sensor has been reported as an instrument to distinguish robusta or arabica coffee. In industry, the aroma of coffee is tested by trained aroma experts which is difficult to replicate because few people have sensitive senses of smell and taste. Industries engaged in the coffee business need a coffee aroma testing system to substitute aroma organoleptic experts. None has reported a sensor to detect a specific coffee odor according to the coffee aroma wheel. In this work, we show that a QCM sensor is a candidate of a coffee aroma sensor. The sensor was coated using polystyrene by a spin coating method. The sensors are installed in a static headspace chamber and showed a response to the aroma of coffee pulp, roasted coffee, and blackcurrant but did not respond to a coffee blossom aroma according to the coffee aroma wheel.