FTIR and Chemometrics as Effective Tools in Predicting the Quality of Specialty Coffees Verônica Belchior 1 & Bruno Gonçalves Botelho 2 & Susana Casal 3 & Leandro S. Oliveira 1,4 & Adriana S. Franca 1,4 Received: 4 April 2019 /Accepted: 26 July 2019 # Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract Cup tasting is the most important tool to access the quality of coffee beans. However, the use of sensory evaluation alone can present some problems, since bias from the previous knowledge of a particular sample and health conditions of the taster can influence the results. Given the well-established potential of spectroscopic methods in coffee quality evaluation, in the present study, we sought to evaluate the potential of FTIR spectroscopy for quantitative evaluation of specialty coffee quality. Samples of specialty coffee were provided by the Federação dos Cafeicultores do Cerrado Mineiro and Fazenda Barinas. They were roasted in IKAWA coffee roaster, analyzed by a group of Q-graders, and submitted to FTIR analysis. Physicochemical analyses (pH, titratable acidity, brix, total solids, and browning compounds) were also employed to show potential differences. Only pH showed significant difference between the beverages. PLS results showed consistent models for predicting the quality previously given by the cuppers, with low values of RMSEC and RMSEP (0.23 both). Also, the models showed high values of Rc (0.99) and Rv (0.97). The whole spectra were considered as important to classify the coffees by their quality, showing the complexity of the beverage. Keywords Cup quality . Chemometrics . Partial least square regression (PLS) . Attenuated total reflectance (ATR) . Fourier transform infrared spectroscopy (FTIR) . Specialty Coffee Association (SCA) Introduction The quality of a cup of coffee begins to be defined when the plant starts to develop. The selected varieties, harvesting and post-harvesting methods applied, and later the roasting pro- cess followed by the elaboration of blends are factors that will greatly influence the final quality of the beverage. The delicate flavor of a cup of coffee is the final expression of a great chain of chemical and physical transformations that link the seed to the cup (Di Donfrancesco et al. 2014; Sunaharum et al., 2014). Cup tasting is the most important and common tool to access the quality of green coffee (Craig et al. 2018; Tolessa et al. 2016). Not only coffee but also tea, perfume, and tobacco industries often use “experts” for this evaluation. The coffee experts, also called “cuppers,” are professionals that accumu- late years of wide knowledge about this product (Di Donfrancesco et al. 2014). Usually, different producing coun- tries have their methods for evaluating coffee (Craig et al. 2018; Santos et al. 2012). But among the available methods for sensory analysis of coffee, those of the “Specialty Coffee Association” (SCA) classification are considered the most suitable for high-quality coffees due to their recommended use of a specific protocol to carry out sensory analysis. These protocols are based on objective assessment methods, such as the presence or absence of sweetness and defects, thus minimizing subjectivity in comparison with other methodolo- gies (Leloup et al. 2004). However, the use of the experts can present some prob- lems. Bias from the preference and knowledge of a particular sample, the influence of external factors, the specific health conditions of the taster, and changes in the personal abilities of evaluation can affect the results. These issues encourage the use of alternative evaluation tools (Di Donfrancesco et al. * Verônica Belchior belchior.veronica@gmail.com 1 PPGCA, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG 31270-901, Brazil 2 DQ, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG 31270-901, Brazil 3 LAQV/REQUIMTE, Faculdade de Farmácia, Universidade do Porto, R. Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal 4 DEMEC, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG 31270-901, Brazil Food Analytical Methods https://doi.org/10.1007/s12161-019-01619-z