Journal of the Brazilian Chemical Society
URI permanente para esta coleção${dspace.url}/handle/123456789/13322
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Item Composition of Coffea canephora Varieties from the Western Amazon(Sociedade Brasileira de Química, 2024-04-05) Acre, Lucas B.; Viencz, Thayna; Francisco, Julyene S.; Rocha, Rodrigo B.; Alves, Enrique A.; Benassi, Marta T.This research aimed to compare the composition profiles of roasted Coffea canephora varieties (conilon, robusta, and intervarietal hybrids) grown in the Western Amazon. Ten coffees of each variety were evaluated. No difference in the contents of caffeine (1427 to 3364 mg 100 g 1) and kahweol (absence to 25.7 mg 100 g 1) was observed. Hybrid coffees were discriminated from traditional varieties (conilon and robusta) and stood out for their higher content of trigonelline, chlorogenic acids, and total diterpenes (mean values of 613,3791, and 471 mg 100 g 1, respectively), higher cafestol/kahweol ratio (7.6 to 15.0), and higher frequency of kahweol presence. Traditional varieties only differed in cafestol and 16-O-methylcafestol contents. Robusta coffees stood out for their lower cafestol content (116 mg 100 g 1), and conilon for their lower 16-O-methylcafestol content (139 mg 100 g 1). Differences between the traditional varieties are smaller than that observed among them and the intervarietal hybrid coffees.Item Authentication of Specialty Coffees from the Fluminense Northwest and Caparaó Regions (Brazil) Using UV-Vis Spectroscopy and Synthetic Samples Partial Least Square Discriminant Analysis (SS-PLS-DA)(Sociedade Brasileira de Química, 2024-02-09) Caldeira, Gabriel R. F.; Costa, Tayná O.; Nascimento, Marcia H. C.; Corradini, Patricia G.; Filgueiras, Paulo R.; Ferreira, Daniel C.; Ferreira, Daniel C.Caparaó and the Fluminense northwest regions are nationally recognized by the important contribution on coffee production and exportation. Adulterations involving specialty coffees result in a decrease in the quality of the final product. However, obtaining many different samples from the same region is unfeasible in some cases, needing strategies to work with a limited number of samples for pattern recognition. Thus, this work is the first to use the construction of synthetic samples (SS) for analysis of coffees, and its objective is to identify adulterations in specialty coffees with bark, straw and low-quality beans, using UV-Vis spectroscopy, associated with chemometric methods. The synthetic samples partial least square discriminant analysis (SS-PLS-DA) showed better specificity, sensitivity and reliability rates than the Hard PLS-DA models. One-class methods (soft independent modeling of class analogy (SIMCA) and data driven soft independent modeling of class analogy (DD-SIMCA)) showed low specificity and reliability. The discriminant methods together with the synthetic samples proved to be adequate to identify adulterations in specialty coffees.Item Ambient mass spectrometry employed for direct analysis of intact arabica coffee beans(Sociedade Brasileira de Química, 2014) Garrett, Rafael; Schwab, Nicolas V.; Cabral, Elaine C.; Henrique, Brenno V. M.; Ifa, Demian R.; Eberlin, Marcos N.; Rezende, Claudia M.The ambient ionization mass spectrometry techniques: desorption electrospray ionization (DESI) and easy ambient sonic-spray ionization (EASI) were explored as fast and simple ways to directly analyze the surface of intact green Arabica coffee beans treated by the dry, semi-dry and wet post-harvest methods. Five compounds were identified, including three components of the waxy layer that covers the green coffee beans (β N-arachinoyl-5-hydroxytryptamide, β N-behenoyl5-hydroxytryptamide, and β N-lignoceroyl-5-hydroxytryptamide) and that are commonly related to related to stomach irritations caused by coffee beverage consumption in sensitive people. Moreover, the multivariate statistical tool principal component analysis (PCA) was employed to differentiate the coffee post-harvest methods using data from the mass spectrometry fingerprinting analyses. Extraction procedures or sample pretreatment steps were not required for DESI and EASI analyses and the results obtained suggest therefore that these techniques could be used for rapid quality control and certification processes of coffees samples.Item Discrimination of commercial roasted and ground coffees according to chemical composition(Sociedade Brasileira de Química, 2012) Souza, Romilaine M. N. de; Benassi, Marta T.Roasted and ground 38 commercial coffees and coffees of known species (arabica, robusta) were characterized by principal component analysis using as variables nicotinic acid, trigonelline, 5-o-caffeoylquinic acid (5-CQA), caffeine, kahweol and cafestol, which are potentially indicative of species. The objective of the study was to assess the relevance of such parameters in coffee discrimination. Nicotinic acid allowed the characterization of roasting degree. Trigonelline and 5-CQA presented variability among arabica and robusta coffees as well as among comercial ones. Thermostable parameters (caffeine, kahweol and cafestol) had high discriminative potential between the species. In general, high levels of caffeine and low levels of diterpenes (kahweol and cafestol) were related with higher proportions of robusta in the products, which were observed by the decreasing kahweol/cafestol ratio and increasing caffeine/kahweol ratio. The use of these new parameters (kahweol/cafestol and caffeine/kahweol ratios) was suggested as tools for assessing the addition of robusta in commercial coffees.Item Differential scanning calorimetry and infrared spectroscopy combined with chemometric analysis to the determination of coffee adulteration by corn(Sociedade Brasileira de Química, 2017) Brondi, Ariadne M.; Torres, Claudia; Garcia, Jerusa S.; Trevisan, Marcello G.Roasted and ground coffee is targeted by fraudulent addiction of products. In this way the determination of contaminants in coffee has economic and nutritional importance. In this study, the coffee adulteration by corn were detected using DSC (differential scanning calorimetry) and FTIR (Fourier transform infrared spectroscopy) coupled to PCA (principal component analysis), and PLS (partial least squares) models. Three different levels of roasted and ground Coffea arabica L. were used to prepare mixtures with roasted and ground corn. The level of adulteration used was between 0.5 to 40% (m/m). It was observed that both DSC and FTIR coupled with PCA are able to discriminate adulterated from unadulterated samples of coffee by corn at levels below 1%. PLS models were built with DSC and FTIR data reaching good correlation between the values of estimated and reference concentrations, with RMSECV (root mean square error of cross-validation) lower than 3.5% for DSC data and 2.7% for FTIR data.