ABSTRACT
Abstract Commercial roasted and ground coffees are usually blends of Coffea arabica and Coffea canephora. Considering the differences in price and sensory characteristics between these two species, the identification of the presence of each species in commercial blends is of great interest. The aim of this study was to describe typical profiles of caffeine and diterpenes (kahweol and cafestol) contents and the ratios among these compounds to support the characterization of Coffea species in roasted coffees. 32 good cup quality Brazilian C. arabica coffees (from coffee quality contests) produced using different postharvest treatments were studied. All analysis were performed by HPLC. Higher ranges were observed in diterpene contents - kahweol varied from 1.75 to 10.68 g/kg (coefficient of variation of 510%) and cafestol from 1.76 to 9.66 g/kg (449%) - than caffeine, that varied from 5.1 to 16.2 g/kg (coefficient of variation of 218%). Wide ranges of the kahweol/cafestol ratio (0.63 to 2.77) and the caffeine/kahweol ratio (0.84 to 5.15) were also observed. Hence it was proposed the additional use of a new parameter, the ratio of caffeine/sum of diterpenes (kahweol + cafestol) that presents values from 0.54 to 2.39. The results indicated that the combined use of these parameters could be a potential tool for discriminating Coffea species in blends of roasted and ground coffee. It was proposed as potentially indicative of C. arabica: values of kahweol/cafestol ratio above 0.50, associated with caffeine/kahweol ratio lower than 5.50 and caffeine/sum of diterpenes ratio lower than 2.50.
Subject(s)
Caffeine/analysis , Coffee/chemistry , Diterpenes/analysis , Coffee Industry , Chromatography, High Pressure LiquidABSTRACT
O presente trabalho refere-se à pesquisa de dois cafés exóticos comercializados no Brasil: o café Jacu, proveniente do estado de Espírito Santo, e o café Civeta procedente da Indonésia (cujos frutos maduros são ingeridos e "processados" no trato digestivo de animais). Suas características químicas e físicas foram comparadas às de cafés torrados e moídos comerciais brasileiros (Tradicional, Superior ou Premium e Gourmet). Os valores referentes à composição centesimal, teor de cafeína (1,04 a 1,45%) e sólidos solúveis totais (24,50 a 32,23%) de todas as amostras atenderam aos limites preconizados pela legislação brasileira. Os cafés exóticos, Jacu e Civeta, apresentaram os maiores e menores parâmetros de cor, respectivamente (L* = 20,46 e 11,55; h* = 58,13 e 51,06 e C* = 21,00 e 14,85). Os maiores teores (média de 35,21 mg em equivalente de ácido gálico/g amostra) de compostos fenólicos totais foram verificados nos cafés Tradicional e Premium. Os cafés Jacu e Gourmet apresentaram os maiores teores de 5-ACQ (média de 0,65%) e de trigonelina (média 0,63 g/100 g amostra) e os menores teores de ácido nicotínico (média de 0,022 g/100 g amostra). O café Premium continha os maiores teores de açúcar total (1,37 g glicose/100 g amostra) e o café Tradicional mostrou o maior teor de açúcares redutores (0,27 g sacarose/100 g amostra). O café Gourmet apresentou a maior acidez titulável total (171,13 mL NaOH 0,1 N/100 g amostra) e o Premium a menor (121,31 mL NaOH 0,1 N/100 g amostra).