Caffeine content of Ethiopian Coffea arabica beans

gmb Genetics and Molecular Biology Genet. Mol. Biol. 1415-4757 1678-4685 Sociedade Brasileira de Genética Ribeirão Preto, SP, Brazil O banco de germoplasma de café do Instituto Agronômico de Campinas contém grande número de introduções de Coffea arabica provenientes da Etiópia, considerada centro de diversidade genética desta espécie. A avaliação dos teores de cafeína nas sementes de 99 progênies revelou a presença de variabilidade entre e dentro das progênies, de acordo com a região de origem das introduções. Entre as 68 progênies da região de Kaffa encontraram-se valores de cafeína entre 0.46 e 2.82% (média 1.18%) e entre as 22 progênies de Illubabor obtiveram-se plantas cujos teores de cafeína variaram de 0.42 a 2.90% (média 1.10%). A variabilidade aqui relatada poderá ser explorada na produção de uma variedade de café com baixos teores de cafeína nas sementes. SHORT COMMUNICATION CAFFEINE CONTENT OF ETHIOPIAN COFFEA ARABICA BEANS Maria Bernadete Silvarolla1, Paulo Mazzafera2 and Marinez Muraro Alves de Lima1 1 Centro de Café e Plantas Tropicais, Instituto Agronômico de Campinas, Caixa Postal 28, 13001-970 Campinas, SP, Brasil. Send correspondence to M.B.S. 2 Departamento de Fisiologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Caixa Postal 6109, 13083-970 Campinas, SP, Brasil. ABSTRACT The coffee germplasm bank of the Instituto Agronômico de Campinas has many Coffea arabica accessions from Ethiopia, which is considered the primary center of genetic diversity in coffee plants. An evaluation of the caffeine content of beans from 99 progenies revealed intra- and inter-progeny variability. In 68 progenies from the Kaffa region we found caffeine values in the range 0.46-2.82% (mean 1.18%), and in 22 progenies from Illubabor region these values ranged from 0.42 to 2.90% (mean 1.10%). This variability could be exploited in a breeding program aimed at producing beans with low-caffeine content. INTRODUCTION Although coffee is a popular beverage mostly due to the alertness caused by caffeine, there is an increasing market for decaffeinated coffee (Mazzafera et al., 1997). Organic solvents or supercritical carbon dioxide is used to decaffeinate coffee, with the final product containing less than 0.5% caffeine (Mazzafera and Carvalho, 1991; Saldaña et al., 1998). Supercritical extraction produces coffee free from chemical residues, the presence of which limits coffee consumption (Mazzafera and Carvalho, 1991). Supercritical extraction also has the advantage of being selective for caffeine without changing the final product quality, although recent studies have shown that other substances, such as sugars, oil and phenolic compounds (Saldaña, M.D.A., Mohamed, R.S. and Mazzafera, P., unpublished data), are also extracted during the process (Peker et al., 1992; Saldaña, 1997). The Arabica coffee bean cultivar "Laurina" has half the content (0.6%) of caffeine found in other Coffea arabica cultivars (1.2%) (Carvalho et al., 1965), and differs from the latter in its peculiar plant architecture and low productivity (Carvalho et al., 1991). Carvalho et al. (1965) showed that these characteristics are recessive (lrlr), with a strong pleiotropic effect. Mazzafera et al. (1992) evaluated the caffeine content of more than 500 coffee trees of C. arabica under selection for productivity and pest and disease resistance and observed little variability in the caffeine content. Breeding programs involving interspecific crosses among C. arabica and low-caffeine content African species resulted in hybrids with a low-caffeine content but with poor vegetative characteristics (Mazzafera and Carvalho, 1992). Problems resulting from strong genetic barriers between C. arabica and other native diploid Coffea species from the Mascarene Islands and Madagascar have been reported (Charrier, 1978; Charrier and Berthaud, 1975; Rakotomalala et al., 1992). The production of low-caffeine coffee bean varieties, using traditional plant breeding methods, is slow and arduous. However, considering the problems associated with the methods of caffeine extraction currently used, the breeding of such plants is still a desirable solution. In the present work, we analyzed Arabica germplasm, originally introduced from Ethiopia, considered to be the primary center of genetic diversity in coffee plants (Medina Filho et al., 1984). The most promising genotypes could be valuable in a breeding program aimed at producing beans with a low-caffeine content, and would help to expand the limited genetic variability of Brazilian coffee (Medina Filho et al., 1984). MATERIAL AND METHODS The Coffea arabica plants studied were originally collected from seven regions in Ethiopia during an FAO expedition in 1964-65 (FAO, 1968). The plants were grown in Turrialba, Costa Rica, and transferred in 1975 to the germplasm bank of the Experimental Center of the Instituto Agronômico de Campinas (IAC). Seeds from 724 plants were analyzed, of which 68 were progenies from the Kaffa region, 22 from Illubabor, five from Gojjam and one each from Eritrea, Geisha, Harar and Shoa. The Brazilian cultivars "Catuaí Vermelho" and "Mundo Novo" (24 plants) were included for comparison. Coffee beans were obtained from at least 20 mature fruits of each plant, and their caffeine content determined by high-performance liquid chromatography (Mazzafera et al., 1997), following extraction. RESULTS AND DISCUSSION The mean caffeine content of 499 plants from the Kaffa region was 1.18% (Table I), although there was high intra- and inter-progeny variability. Mean caffeine contents as low as 0.46% and as high as 2.82% were found. In the 166 plants from the Illubabor region, caffeine content ranged from 0.42 to 2.90% (Table II). The plants from Gojjam, Eritrea, Geisha, Harar and Shoa (Table III) did not show the extreme values seen in the other two regions, probably because of the small number of plants analyzed. These results show that some Ethiopian plants have a caffeine content lower than those of the reference cultivars "Catuaí Vermelho" and "Mundo Novo". However, the low productivity of the Ethiopian germplasm (Carvalho, A., Fazuoli, L.C. and Guerreiro Filho, O., unpublished data) limits their use and would require a hybridization program to produce high-yield cultivars. The identification of some Ethiopian genotypes with a low-caffeine content confirms previous reports on the genetic variability of these accessions for a number of traits. Carvalho et al. (1983) reported variability in fruit shape, size, weight and color, and Mazzafera et al. (1989) identified male-sterile plants. In an early study, Carvalho (1959) evaluated a group of Ethiopian plants introduced to Brazil in 1952 and 1953 and identified additional factors of economic interest, such as the recessive allele "semi-erecta", which is responsible for a change in the lateral branch intersection of the stems. Plants with coffee leaf rust resistance were also identified. ACKNOWLEDGMENTS The authors thank Denise Cristina da Silva for help with the caffeine analyses. Research partially supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (Proc. No. 94/1775-3). P.M. and M.M.A.L. are recipients of CNPq fellowships. Publication supported by FAPESP. RESUMO O banco de germoplasma de café do Instituto Agronômico de Campinas contém grande número de introduções de Coffea arabica provenientes da Etiópia, considerada centro de diversidade genética desta espécie. A avaliação dos teores de cafeína nas sementes de 99 progênies revelou a presença de variabilidade entre e dentro das progênies, de acordo com a região de origem das introduções. Entre as 68 progênies da região de Kaffa encontraram-se valores de cafeína entre 0.46 e 2.82% (média 1.18%) e entre as 22 progênies de Illubabor obtiveram-se plantas cujos teores de cafeína variaram de 0.42 a 2.90% (média 1.10%). A variabilidade aqui relatada poderá ser explorada na produção de uma variedade de café com baixos teores de cafeína nas sementes. (Received November 9, 1998) Carvalho, A. (1959). A genética de Coffea: XXIV - Mutantes de Coffea arabica procedentes da Etiópia. Bragantia 18: 353-371. A genética de Coffea: XXIV - Mutantes de Coffea arabica procedentes da Etiópia Bragantia 1959 353 371 18 Carvalho A. Carvalho, A., Tango, J.S. and Monaco, L.C. (1965). Genetic control of caffeine in coffee. Nature 205: 314. Genetic control of caffeine in coffee Nature 1965 314 205 Carvalho A. Tango J.S. Monaco L.C. Carvalho, A., Fazuoli, L.C., Levy, F.A., Guerreiro Filho, O. and Mazzafera, P. (1983). Observaçőes sobre características dos frutos de introduçőes de Coffea arabica da Etiópia. In: 10o Congresso Brasileiro de Pesquisas Cafeeiras, 1983. Resumos, pp. 90-92. Resumos 1983 90 92 Carvalho A. Fazuoli L.C. Levy F.A. Guerreiro Filho O. Mazzafera P. Carvalho, A., Medina Filho, H.P., Fazuoli, L.C., Guerreiro Filho, O. and Lima, M.M.A. (1991). Aspectos genéticos do cafeeiro. Rev. Bras. Genet. 14: 135-183. Aspectos genéticos do cafeeiro Rev. Bras. Genet. 1991 135 183 14 Carvalho A. Medina Filho H.P. Fazuoli L.C. Guerreiro Filho O. Lima M.M.A. Charrier, A. (1978). La structure génétique des caféiers spontanés de la région Malgache (Mascarocoffea). Leur relations avec les caféiers d'origene africaine (Eucoffea). Mémoires ORSTOM, 87, ORSTOM, Paris. La structure génétique des caféiers spontanés de la région Malgache (Mascarocoffea): Leur relations avec les caféiers d'origene africaine (Eucoffea) 1978 87 Charrier A. Charrier, A. and Berthaud, J. (1975). Variation de la teneur em caféine dans le genre Coffea. Café Cacao Thé 19: 251-264. Variation de la teneur em caféine dans le genre Coffea Café Cacao Thé 1975 251 264 19 Charrier A. Berthaud J. Food and Agriculture Organization of the United Nations (1968). Coffee Mission to Ethiopia 1964-65. FAO, Rome. Coffee Mission to Ethiopia 1964-65 1968 Mazzafera, P. and Carvalho, A. (1991). A Cafeína do Café. Documentos IAC, 25. Instituto Agronômico, Campinas. A Cafeína do Café 1991 25 Mazzafera P. Carvalho A. Mazzafera, P. and Carvalho, A. (1992). Breeding for low seed caffeine content of coffee (Coffea L.) by interspecific hybridization. Euphytica 59: 55-60. Breeding for low seed caffeine content of coffee (Coffea L. by interspecific hybridization) Euphytica 1992 55 60 59 Mazzafera P. Carvalho A. Mazzafera, P., Eskes, A.B., Parvais, J.P. and Carvalho, A. (1989). Stérilité mâle détectée chez Coffea arabica et C. canephora au Brésil. In: 13th International Scientific Colloquium on Coffee, 1989. Annals, pp. 466-473. Stérilité mâle détectée chez Coffea arabica et C. canephora au Brésil 1989 466 473 Mazzafera P. Eskes A.B. Parvais J.P. Carvalho A. Mazzafera, P., Carvalho, A., Fazuoli, L.C. and Medina Filho, H.P. (1992). Variabilidade do teor de cafeína em sementes de café. Turrialba 42: 231-237. Variabilidade do teor de cafeína em sementes de café Turrialba 1992 231 237 42 Mazzafera P. Carvalho A. Fazuoli L.C. Medina Filho H.P. Mazzafera, P., Silvarolla, M.B., Lima, M.M.A. and Medina Filho, H.P. (1997). Caffeine content of diploid coffee species. Cięn. Cult.49: 216-218. Caffeine content of diploid coffee species Ciên. Cult. 1997 216 218 49 Mazzafera P. Silvarolla M.B. Lima M.M.A. Medina Filho H.P. Medina Filho, H.P., Carvalho, A., Sondahl, M.R., Fazuoli, L.C. and Costa, W.M. (1984). Coffee breeding and related evolutionary aspects. In: Plant Breeding Reviews (Janick, J., ed.). The Avi Publishing Co. Inc., Westport, Connecticut, pp. 157-193. Plant Breeding Reviews 1984 157 193 Medina Filho H.P. Carvalho A. Sondahl M.R. Fazuoli L.C. Costa W.M. Janick J. Peker, H., Srinivasan, M.P., Smith, J.M. and McCoy, J.B. (1992). Caffeine extraction rates from coffee beans with supercritical carbon dioxide. Am. Inst. Chem. Eng. Symp. Ser. 38: 761-770. Caffeine extraction rates from coffee beans with supercritical carbon dioxide Am. Inst. Chem. Eng. Symp. Ser. 1992 761 770 38 Peker H. Srinivasan M.P. Smith J.M. McCoy J.B. Rakotomalala, J.J.R., Cros, E., Clifford, M.N. and Charrier, A. (1992). Caffeine and theobromine in green beans from Mascarocoffea. Phytochemistry 31: 1271-1272. Caffeine and theobromine in green beans from Mascarocoffea Phytochemistry 1992 1271 1272 31 Rakotomalala J.J.R. Cros E. Clifford M.N. Charrier A. Saldańa, M.D.A. (1997). Extraçăo de cafeína, trigonelina e ácido clorogęnico dos grăos de café com CO2 supercrítico. Master's thesis, Faculdade de Engenharia Química, UNICAMP. Extração de cafeína, trigonelina e ácido clorogênico dos grãos de café com CO2 supercrítico 1997 Saldaña M.D.A. Saldańa, M.D.A., Mazzafera, P. and Mohamed, R.S. (1998). Extraçăo dos alcalóides cafeína e trigonelina dos grăos de café com CO2 supercrítico. Cięnc. Tecnol. Aliment. 17: 371-376. Extração dos alcalóides cafeína e trigonelina dos grãos de café com CO2 supercrítico Ciênc. Tecnol. Aliment. 1998 371 376 17 Saldaña M.D.A. Mazzafera P. Mohamed R.S.