In this work, the applicability of

In this work, the applicability of NIR spectroscopy to perform real-time in-situ monitoring of an organoleptic characteristic, coffee acidity, during the roasting process, was studied. To the best of our knowledge, exploiting NIR technique as a tool to monitor in-situ coffee organoleptic characteristics has not been exploited. Perceived acidity is one of the key perceptions within the coffee organoleptic profile (Franca, Mendonça, & Oliveira, 2005). In the first stage, this characteristic depends on the coffee origin, variety and processing method of the coffee cherries. Usually, coffees cultivated at higher altitudes or subjected to post-harvest wet-processing treatment present higher acidity (Balzer, 2001). Furthermore, the perceived acidity depends on the final quantity of acids present (and further extracted) which is mainly related with the roasting degree. A very acidic perception (sourness) may be considered as a coffee defect. Very roasted and slightly roasted coffees present lower perceived acidity (Flament, 2002, chap. 5). Although it is not clear which compounds are responsible for the perceived acidity, it is known that citric, malic, acetic, quinic and mainly chlorogenic acids, are the most abundant acid species in coffee bean and may be responsible for this organoleptic characteristic