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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item Antioxidants, phenols, caffeine content and volatile compounds in coffee beverages obtained by different methods(Sociedade Brasileira de Ciência e Tecnologia de Alimentos, 2022-07-15) Chavez, Segundo Grimaldo; Mendoza, Marilu Mestanza; Caetano, Aline CamilaThe objective of the research was to evaluate the antioxidant activity, phenols and volatile compounds of different types coffee infusions. We worked with the Catimor coffee variety and used five methods to obtain the infusion (espresso, V60, siphon, French press and a traditional local method). For each infusion, the antioxidant capacity was determined with the 2,2-Diphenyl-1-Picrylhydrazyl and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid techniques, the phenolic content was determined with the Folin-Ciocalteu technique, and aromatic volatile compounds were determined with gas chromatography coupled with mass spectrometry. The extraction method that yielded the coffee infusions with the most antioxidant activity, phenolic compounds and caffeine content was espresso; however, this coffee had the fewest aromatic volatile compounds. Although they had lower antioxidant activity, the infusions obtained with the French press had the highest content of volatile aromatic compounds and produced a cup that was free of pyridine, an undesirable compound in coffee due to its rotten smell.Item Tasters’ performance in a coffee quality contest in Brazil(Editora UFLA, 2021) Pinheiro, Aracy Camilla Tardin; Fabri Júnior, Marcos Antônio; Cruz, Cosme Damião; Rufino, José Luis dos Santos; Sakiyama, Ney SussumuThe objective of this work was to evaluate the performance of coffee tasters in five annual editions of Minas Gerais Coffee Quality Contest. The repeat ability coefficients of the tasters’ scores for sensory attributes were estimated, as well as the minimum numbers of tasters required for consistent sensory results, and the groups of tasters by (dis)similarity of sensory scores. For the repeatability analysis, the treatments (coffees) were tested with the repeti tions, constituted by the tasters. The repeatability coefficients were estimated using the analysis of variance, principal component and structural analysis methods. The minimum number of tasters was obtained based on pre-established determination coefficients. Euclidean distance matrices between tasters were determined, which were used as a measure of dissimilarity for cluster analysis by the Tocher optimization method. The tasters’ performance in five annual editions of Minas Gerais Coffee Quality Contest is reliable using COE or SCA sensory analysis protocols. Although not fully calibrated, most tasters are grouped with similar cupping results. Unless efficient calibration prior to the contest is adopted, the number of tasters to be used in the next contest editions can not be drastically and randomly reduced, since the estimated minimum number varied over the years. Calibration activities are sug gested to improve two main aspects of the Minas Gerais Coffee Quality Contest: distinguishing the best coffees and trainning tasters.Item Effect of roast degree, preparation method, and variety in the sensory and chemical characteristics of coffee (coffea arabica): a mid-infrared spectrum analysis(Editora UFLA, 2021) Barrios-Rodríguez, Yeison Fernando; Córdoba, Gisela-Andrea; Bahamón-Monje, Andrés Felipe; Gutiérrez-Guzmán, NelsonIn coffee beverages, there are several factors that affect the final compounds and generate sensory variations. This study evaluated the effect of five preparation methods, three roast degrees, and three different varieties (coffea arabica) on the physicochemical compounds of coffee (coffea arabica) be fore and after preparation by using information obtained from the mid-infrared spectrum. The effect on some sensory attributes was assessed by means of a panel of 54 habitual coffee consumers. Spectrum data were processed using hierarchical clustering and principal component analysis (PCA), while a mixed general linear model was applied for sensory analysis. The results showed that each factor behaves independently, showing a significant effect (p < 0.05) on a greater number of attributes. The preparation method and the roast degree are attributed to the changes generated in the chemical character istics of coffee during these processes. Through the analysis of the infrared spectrum (IR) by hierarchical cluster, it was found that, before the preparation of the coffee drinks, the samples are grouped by roast degree, regardless of the type of variety. Spectrum analysis by PCA after brewing indicated that there is a greater effect of the roast degree and variety of coffee (coffea arabica) on the chemical markers of the IR spectra. Finally, wavelengths 1,800, 1,740, 1,650, 1,550, 1,480, 1,150, and 710 cm-1, which had a greater contribution in the PCA and allowed the evaluated samples to be grouped differently, are those related to non-volatile compounds such as caffeine, chlorogenic acids, and trigonelline, which provide sensory characteristics to the final drink.