Discrimination of commercial roasted and ground coffees according to chemical composition

Abstract

Cafés torrados e moídos comerciais (38 amostras) e cafés com espécie conhecida (arábica e robusta) foram caracterizados por análise de componentes principais, utilizando-se como variáveis, ácido nicotínico, trigonelina, ácido 5-o-cafeoilquínico (5-CQA), cafeína, caveol e cafestol, potencialmente indicadoras das espécies. O estudo objetivou avaliar a importância desses parâmetros na discriminação entre cafés. Ácido nicotínico foi eficiente na caracterização da torra. Trigonelina e 5-CQA destacaram-se pela variabilidade, tanto entre as amostras puras, como nos cafés comerciais. O maior potencial de discriminação entre as espécies foi atribuído aos parâmetros termoestáveis (cafeína, caveol e cafestol). No geral, maiores teores de cafeína e menores de diterpenos (caveol e cafestol) foram relacionados a proporções de robusta mais elevadas no produto, constatando-se uma tendência de diminuição na razão caveol/cafestol e aumento na razão cafeína/caveol. Esses dois novos parâmetros (razões caveol/cafestol e cafeína/caveol) foram propostos como ferramentas para avaliação da adição de robusta em cafés comerciais.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 commercial 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.Keywords: arabica, robusta, pca, kahweol/cafestol, caffeine/kahweol IntroductionCoffee is one of the main food commodities in the worldwide economy, and it is the most consumed beverage after tea. 1 Brazil is the world leader in the production and exportation of coffee 2 because Brazil is a heavy producer of both Coffea arabica (arabica) and Coffea canephora (robusta) species. 3 Arabica and robusta coffees differ considerably in price, sensorial quality and acceptance. 2,4 In general, arabica coffee has a higher concentration of carbohydrates, lipids and trigonelline in the green and roasted products, providing a superior sensorial cup quality, and robusta coffee has high levels of caffeine. [5][6][7][8] Conversely, robusta coffee is widely accepted in market due to its low cost, and it is considerably used in blends with arabica....

Composição química de cafés árabica de cultivares tradicionais e modernas

“…Isto mostra que esse comportamento acontece mesmo que haja a participação da cultivar tradicional no cruzamento. Souza & Benassi (2012) e IPR 99), não foi possível fazer uma associação entre a origem do cruzamento e a concentração de cada composto. Pela ACP foi possível analisar a influência simultânea dos compostos na discriminação das cultivares e verificar quais componentes ou conjunto de componentes poderiam ser indicadores de mudanças obtidas pela introgressão de genes de C. canephora.…”

Caffeine Consumption through Coffee: Content in the Beverage, Metabolism, Health Benefits and Risks

“…The effect of environment, agricultural practices, including the use of fertilizers, and post-harvest processing on methylxanthines contents seems to be less important than genetic aspects, except in the case of secondary processing, such as decaffeination [38][39][40]. The range of caffeine contents reported for green C. arabica L. vary in the literature between 0.7 and 1.7 g/100 g (dry matter-dm) [15,26,38,[41][42][43][44][45][46][47][48][49][50][51][52], while those for C. canephora vary in the range between 1.4 and 3.3 g/100 g (dm) [26,38,41,42,45,49,50,[52][53][54][55][56]. However, common values are in a narrower range, between 1.0 and 1.2 g/100 g, dw, for C. arabica [15,44,[46][47][48][49][50][51]54], and between 1.7 and 2.1 g/100 g (dm) for C. canephora [26,39,43,51,55,56].…”

Diterpenes biochemical profile and transcriptional analysis of cytochrome P450s genes in leaves, roots, flowers, and during Coffea arabica L. fruit development

“…CAF and KAH concentrations have mainly been evaluated in ripe fruit and in green or toasted coffee grains (Dias et al, 2010;Kitzberger et al, 2013). Most studies were performed to discriminate commercial roasted and ground coffees according to chemical composition (De Souza and Benassi, 2012). However, there is no study that addresses the accumulation dynamics of CAF and KAH during C. arabica fruit development, particularly during their initial growth stages.…”