Análise do óleo essencial de variedades de lúpulo (Humulus lupulus L.) cultivadas no Brasil por cromatografia gasosa uni e bidimensional
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Data
2020-02-28
Autores
Almeida, Juliana Machado
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Universidade Estadual Paulista (Unesp)
Resumo
Pertencente à família Cannabaceae, o lúpulo (Humulus lupulus L.) é considerado um dos ingredientes mais importante da cerveja por proporcionar amargor e odor na bebida, devido aos α-ácidos e β-ácidos e ao óleo essencial presentes nas inflorescências femininas. Os óleos essenciais são responsáveis pelo perfil aromático das variedades de lúpulo, podendo variar de 0,5 a 3% de teor nos cones secos. No Brasil, o cultivo de lúpulo ainda é recente e advém de iniciativas de agricultores, em boa parte, de pequena escala, com potencial de crescimento desse nicho de mercado. Para o fomento da mesma, é importante analisar o perfil químico dos óleos essenciais, uma vez que, fatores genéticos, ambientais, de cultivo, época de colheita e processamento do material vegetal podem afetar sua composição química. O objetivo desse estudo foi caracterizar a composição química dos óleos essenciais de variedades de Humulus lupulus, cultivadas em diferentes localidades no Brasil. No total foram avaliadas 18 amostras de 13 variedades (Cascade, Chinook, TP, Medusa, Suíço, Mantiqueira, Saaz, EKG1, Columbus, Comet, Hallertau Mittelfrüch, Brazylinsk e Nugget) provenientes dos estados de São Paulo, Rio Grande do Sul e Rio de Janeiro, safra de 2019. Os óleos essenciais foram extraídos por hidrodestilação em aparato Clevenger por três horas, a partir de 45 g de cones secos. A análise da composição química dos óleos essenciais foi realizada por cromatografia em fase gasosa acoplada a espectrometria de massas (CG-EM) e cromatografia em fase gasosa bidimensional abrangente acoplada a espectrometria de massas (CG×CG-EM). Os rendimentos dos óleos essenciais variaram de 0,09 % (Chinook/SP) a 2,29 % (Cascade/RJ). Houve variação do perfil químico entre as variedades. O mirceno, responsável por prover odor herbal no lúpulo, foi o constituinte majoritário em 15 amostras, seguido por α-humuleno (variedade Medusa, L09) e β-farneseno (Cascade/SP: L04, e Saaz/RJ: L05). A técnica CG×CG-EM possibilitou a identificação adicional de 14 substâncias em relação a CG-EM
Belonging to the Cannabaceae family, hop (Humulus lupulus L.) is considered one of the most important ingredients in beer by providing the bitterness and odor of the drink due to α and β-acids and to the essential oil present in its female inflorescences. Essential oils are responsible for the aromatic profile of hop varieties, ranging from 0.5 to 3% of the content in dry cones. In Brazil, the cultivation of hops is still recent and comes from initiatives of small farmers with potential expansion of this market niche. However, to promote it, it is important to analyze the essential oils chemical profile, since genetic, environment and cultivation factors, as well as harvest season and plant material processing might affect its chemical composition. Thus, the aim of this study was to characterize the chemical composition of essential oils of Humulus lupulus varieties, cultivated in different locations of Brazil. In total, 18 samples of 13 varieties (Cascade, Chinook, TP, Medusa, Suíço, Mantiqueira, Saaz, EKG1, Columbus, Comet, Hallertau Mittelfrüch, Brazylinsk and Nugget) from São Paulo, Rio Grande do Sul and Rio de Janeiro states were evaluated, from a 2019 harvest. The essential oils were extracted by hydrodistillation in Clevenger apparatus for three hours, from 45 g of dry cones. The analysis of the chemical composition of essential oils was performed by gas chromatography coupled to mass spectrometry (GC-MS) and Comprehensive two dimensional gas chromatography coupled to mass spectrometry (GCxGC-MS). The essential oil yields ranged from 0.09 % (Chinook/SP) to 2.29 % (Cascade/RJ). There was variation in the chemical profile between the varieties. Myrcene, compound responsible for providing herbal odor in hops, was the major constituent in 15 samples, followed by α-humulene (Medusa variety, L09) and β-farnesene (Cascade / SP: L04, and Saaz / RJ: L05). The GCxGC-MS technique allowed the additional identification of 14 substances in relation to GC-MS.
Belonging to the Cannabaceae family, hop (Humulus lupulus L.) is considered one of the most important ingredients in beer by providing the bitterness and odor of the drink due to α and β-acids and to the essential oil present in its female inflorescences. Essential oils are responsible for the aromatic profile of hop varieties, ranging from 0.5 to 3% of the content in dry cones. In Brazil, the cultivation of hops is still recent and comes from initiatives of small farmers with potential expansion of this market niche. However, to promote it, it is important to analyze the essential oils chemical profile, since genetic, environment and cultivation factors, as well as harvest season and plant material processing might affect its chemical composition. Thus, the aim of this study was to characterize the chemical composition of essential oils of Humulus lupulus varieties, cultivated in different locations of Brazil. In total, 18 samples of 13 varieties (Cascade, Chinook, TP, Medusa, Suíço, Mantiqueira, Saaz, EKG1, Columbus, Comet, Hallertau Mittelfrüch, Brazylinsk and Nugget) from São Paulo, Rio Grande do Sul and Rio de Janeiro states were evaluated, from a 2019 harvest. The essential oils were extracted by hydrodistillation in Clevenger apparatus for three hours, from 45 g of dry cones. The analysis of the chemical composition of essential oils was performed by gas chromatography coupled to mass spectrometry (GC-MS) and Comprehensive two dimensional gas chromatography coupled to mass spectrometry (GCxGC-MS). The essential oil yields ranged from 0.09 % (Chinook/SP) to 2.29 % (Cascade/RJ). There was variation in the chemical profile between the varieties. Myrcene, compound responsible for providing herbal odor in hops, was the major constituent in 15 samples, followed by α-humulene (Medusa variety, L09) and β-farnesene (Cascade / SP: L04, and Saaz / RJ: L05). The GCxGC-MS technique allowed the additional identification of 14 substances in relation to GC-MS.
Descrição
Palavras-chave
Terpenos, Mirceno, Cannabaceae, Constituintes químicos, Terpenes, Myrcene, Cannabaceae, Chemical contituents