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Caffeine, trigonelline and nicotinic acid are important bioactive constituents of coffee. In this work, the combination of different water temperatures and pressures in the settings of the espresso coffee (EC) machine was evaluated, to assess how these factors influence how effectively caffeine, trigonelline and nicotinic acid are extracted from both Arabica and Robusta samples. The proposed analytical method, based on a high performance liquid chromatography (HPLC) system coupled to a variable wavelength detector (VWD), showed good linearity (R²> 0.9985) and good recoveries (71-92%); after validation for three monitored compounds, the method was used to analyze 20 commercial samples. The combination of a temperature of 92 °C and pressure at 7 or 9 bar seems to be the ideal setting for the most efficient extraction of these compounds and consequently for their intake; the compound extracted in the greatest quantity was caffeine, which was in the range of 116.87-199.68 mg in a 25 ml cup of coffee.

Recebido em 23/10/08; aceito em 16/3/09; publicado na web em 31/8/09 SENSORY EVALUATION OF CACHAÇA. The hedonic level of commercial cachaças, was evaluated by consumers and by a tasters. The results of sensorial methods analyzed trough Principal Components Analysis, Hierarchical Cluster Analysis and the Pearson linear correlation indicated that the best classified cachaças were produced in copper stills and aged in oak casks. By contrast the worst classified exhibited as the main features be not aged and high alcohol percentage. The index of preference is positively correlated with the intensity of yellow color, wood flavor, sweetness and fruit aroma. There is a negative preference correlation with the acidity, the taste of alcohol and bitterness.Keywords: cachaça; sensory analysis; hedonic level. INTRODUÇÃOA cachaça, destilado do vinho obtido a partir do mosto fermentado de cana-de-açúcar, gerou uma receita de US$ 14,4 milhões em 2007.1 Este valor tende a aumentar em virtude dos esforços para a sua comercialização no exterior e da denominação de origem que classificou a cachaça como sendo um produto típico do Brasil pelo Decreto nº. 4062 A cachaça é muito apreciada por seu sabor e aroma característicos, que são decorrentes dos processos de fermentação, destilação e envelhecimento em tonéis de madeira, sendo denominada cachaça envelhecida a bebida que contiver no mínimo 50% de aguardente de cana envelhecida em barris de madeira, por um período não inferior a 1 ano, podendo ser adicionada de caramelo para a correção da cor. 14 Claramente impulsionado pela necessidade de conquista do mercado externo, existe um esforço do setor produtivo e dos laboratórios de pesquisa para a melhoria da qualidade da cachaça. A descrição qualitativa e quantitativa dos compostos químicos presentes em cachaça tem recebido constante atenção por parte de diversos Laboratórios. No entanto, a caracterização da cachaça somente sobre o ponto de vista químico, apesar de extremamente relevante, não é suficiente, necessitando ser complementada pelo conhecimento dos atributos sensoriais da bebida.A definição das substâncias de impacto sensorial que compõem uma bebida destilada é fundamental no monitoramento da produção, na modificação de suas características e para o controle de sua qualidade. A correlação entre os componentes responsáveis pelo aroma, sabor e aspecto visual com a qualidade da bebida são objetos da análise sensorial. Essa continua sendo a principal forma de avaliar a aceitação das mesmas pela percepção humana.

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Introduction In the last years, consumers increased the demand for high-quality and healthy beverages, including coffee. To date, among the techniques potentially available to determine the overall quality of coffee beverages, metabolomics is emerging as a valuable tool. Objective In this study, 47 ground coffee samples were selected during the 2018 Edition of the “International coffee tasting” (ICT) in order to provide discrimination based on both chemical and sensory profiles. In particular, 20 samples received a gold medal (“high quality” group), while lower sensory scores characterized 27 samples (without medal). Methods Untargeted metabolomics based on ultra-high pressure liquid chromatography coupled with quadrupole-time-of-flight (UHPLC-QTOF) and head space-gas chromatography coupled with mass spectrometry platforms followed by multivariate statistical approaches (i.e., both supervised and unsupervised) were used to provide new insight into the searching of potential markers of sensory quality. Results Several compounds were identified, including polyphenols, alkaloids, diazines, and Maillard reaction products. Also, the headspace/GC-MS highlighted the most important volatile compounds. Polyphenols were scarcely correlated to the sensory parameters, whilst the OPLS-DA models built using typical coffee metabolites and volatile/Maillard compounds possessed prediction values > 0.7. The “high quality” group showed specific metabolomic signatures, thus corroborating the results from the sensory analysis. Overall, methyl pentanoate (ROC value = 0.78), 2-furfurylthiol (ROC value = 0.75), and L-Homoserine (ROC value = 0.74) established the higher number of significant (p < 0.05) correlations with the sensory parameters. Conclusion Although ad-hoc studies are advisable to further confirm the proposed markers, this study demonstrates the suitability of untargeted metabolomics for evaluating coffee quality and the potential correlations with the sensory attributes. Graphic abstract