Banco Ativo de Germoplasma de Minas Gerais (Coffea spp.): aptidão para a produção de Cafés Especiais
Data
2017-06-20
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Editor
Universidade Federal de Lavras
Resumo
Um dos principais instrumentos que a atual cafeicultura brasileira dispõe para se manter no mercado, é a qualidade. Em decorrência da crescente demanda por cafés com alta qualidade de bebida, o interesse no plantio de cultivares de maior potencial para produção de cafés especiais tem aumentado significativamente nos últimos anos. Logo, iniciativas de estudos da qualidade de diferentes genótipos gera informações importantes sobre o futuro da produção de cafés especiais no Brasil. Portanto, este trabalho teve por objetivos avaliar os acessos do Banco Ativo de Germolasma de Minas Gerais quanto: i) ao potencial de qualidade dos acessos em função de duas colheitas consecutivas e caracterizar o perfil sensorial dos mesmos; ii) a influência dos processamentos via úmida e via seca na qualidade e no perfil sensorial dos acessos; iii) a encontrar possíveis marcadores químicos para discriminar grupos genealógicos de Coffea arabica processados pelo método via seca utilizando a análise discriminante parcial de mínimos quadrados (PLS-DA); iv) avaliar a discriminação dos acessos processados pelo despolpamento através de um modelo de classificação PLS-DA. O experimento foi conduzido no Banco Ativo de Germoplasma de Minas Gerais (BAG) situado no Campo Experimental da Epamig em Patrocínio, na região Cerrado de Minas, no qual foram avaliados 56 acessos de C. arabica L., implantados no campo em blocos ao acaso com duas repetições e dez plantas por parcela. Os frutos maduros de cada parcela foram colhidos na safra 2015/2016 e processados pelo método via úmida (despolpado) e via seca (natural), secos sob a mesma condição em peneiras de fundo telado até teor de água de 11% (bu). A análise sensorial foi realizada por provadores treinados de acordo com os protolos da SCAA e as análises químicas foram desenvolvidas por métodos cromatográficos e físicoquímicos. Para a interpretação dos dados foram utilizadas as análises quimiométricas PCA e PLS-DA, e para a caracterização das nuances sensoriais utilizou-se o método de Análise de Conteúdo. Os resultados deste estudo demonstram que o banco de germoplasma de Minas Gerais representa uma importante coleção de genótipos com elevado potencial de qualidade de bebida que podem ser aproveitados em programas de melhoramento visando a produção de cultivares para o mercado de cafés especiais. O ano de colheita e o tipo de processamento adotado influenciaram na qualidade e nas características sensoriais de alguns acessos. A classificação dos grupos genealógicos do banco de germoplasma de Minas Gerais através da abordagem química usando a técnica PLS-DA permitiu identificar marcadores químicos para discriminar os genótipos tanto pelo processamento via úmida como pelo processamento via seca, e quais deles apresentam maior influência na resposta da análise. Este estudo mostrou também que o modelo PLS-DA é uma boa ferramenta para discriminar acessos de C. arabica, porém para cultivares com fundo genético diferentes, a classificação não é totalmente satisfatória, sendo necessário aperfeiçoamento do modelo para classificar essas cultivares.
One of the main instruments that the current Brazilian coffee has to stay on the market, is the quality. As a result of the growing demand for high quality coffees, the interest in planting cultivars of great potential for specialty coffee production has increased significantly in recent years. Hence, initiatives of study quality of different genotypes yield important information about the future of specialty coffee production in Brazil. Therefore, this work aims to evaluate the accesses to Active Germplasm Collection of Minas Gerais as: i) the potential of quality of access in function of two consecutive harvests and characterize the sensory profile of the same; ii) the influence of wet and dry processing in quality and sensory profile of the accesses; iii) to find possible chemical markers to discriminate genealogic groups of Coffea arabica processed by dry method using the partial least-squares discriminant analysis (PLS-DA); iv) to evaluate the discrimination of access processed by pulping through a ranking model PLS-DA. The experiment was conducted at the Active Germplasm Collection of Minas Gerais (BAG) located at Fazenda Experimental da Epamig in Patrocínio, in the Cerrado region of Minas Gerais, in which were evaluated 56 accesses of C. arabica L., deployed in the field in random blocks with two replications and ten plants per plot. The ripe fruits of each plot were collected on crop 2015/2016 and processed by the wet method (fully washed) and dry (natural), dried under the same condition on screenhouse bottom sieves until water content of 11% (wu). The sensory analysis was performed by trained tasters in accordance with the protocols of the SCAA and the chemical analyses were developed by chromatographic and physicochemical methods. For the interpretation of the data it was used chemometric analysis PCA and PLS-DA, and to the characterization of the sensorial nuances it was used the method of Content Analysis. The results of this study demonstrate that the Active Germplasm Collection of Minas Gerais represents an important collection of genotypes with high potential for quality of drink that can be used in breeding programs aiming the production of plant varieties to the market of specialty coffees. The year of harvesting and the processing type adopted influenced in quality and sensory characteristics of some accesses. The classification of genealogic groups from the Active Germplasm Collection of Minas Gerais through the chemical approach using PLS-DA has identified chemical markers for discriminating genotypes by both wet and dry processing, and which ones have a higher influence on analysis response. This study also showed that the model PLS-DA is a good tool to discriminate between accesses of C. arabica, however for cultivars with different genetic background, the classification is not entirely satisfactory, being necessary improvement in the model to sort these cultivars.
One of the main instruments that the current Brazilian coffee has to stay on the market, is the quality. As a result of the growing demand for high quality coffees, the interest in planting cultivars of great potential for specialty coffee production has increased significantly in recent years. Hence, initiatives of study quality of different genotypes yield important information about the future of specialty coffee production in Brazil. Therefore, this work aims to evaluate the accesses to Active Germplasm Collection of Minas Gerais as: i) the potential of quality of access in function of two consecutive harvests and characterize the sensory profile of the same; ii) the influence of wet and dry processing in quality and sensory profile of the accesses; iii) to find possible chemical markers to discriminate genealogic groups of Coffea arabica processed by dry method using the partial least-squares discriminant analysis (PLS-DA); iv) to evaluate the discrimination of access processed by pulping through a ranking model PLS-DA. The experiment was conducted at the Active Germplasm Collection of Minas Gerais (BAG) located at Fazenda Experimental da Epamig in Patrocínio, in the Cerrado region of Minas Gerais, in which were evaluated 56 accesses of C. arabica L., deployed in the field in random blocks with two replications and ten plants per plot. The ripe fruits of each plot were collected on crop 2015/2016 and processed by the wet method (fully washed) and dry (natural), dried under the same condition on screenhouse bottom sieves until water content of 11% (wu). The sensory analysis was performed by trained tasters in accordance with the protocols of the SCAA and the chemical analyses were developed by chromatographic and physicochemical methods. For the interpretation of the data it was used chemometric analysis PCA and PLS-DA, and to the characterization of the sensorial nuances it was used the method of Content Analysis. The results of this study demonstrate that the Active Germplasm Collection of Minas Gerais represents an important collection of genotypes with high potential for quality of drink that can be used in breeding programs aiming the production of plant varieties to the market of specialty coffees. The year of harvesting and the processing type adopted influenced in quality and sensory characteristics of some accesses. The classification of genealogic groups from the Active Germplasm Collection of Minas Gerais through the chemical approach using PLS-DA has identified chemical markers for discriminating genotypes by both wet and dry processing, and which ones have a higher influence on analysis response. This study also showed that the model PLS-DA is a good tool to discriminate between accesses of C. arabica, however for cultivars with different genetic background, the classification is not entirely satisfactory, being necessary improvement in the model to sort these cultivars.
Descrição
Tese de Doutorado defendida na Universidade Federal de Lavras
Palavras-chave
Cafés especiais, Qualidade de bebida, Composição química, Banco de germoplasma, Processamento pós-colheita, Specialty coffees, Quality of drink, Chemical composition, Germplasm bank, Post-harvest processing
Citação
FASSIO, Larissa de Oliveira. Banco Ativo de Germoplasma de Minas Gerais (Coffea spp.): aptidão para a produção de Cafés Especiais. 2017. 100 p. Tese (Doutorado em Ciência dos Alimentos) -Universidade Federal de Lavras, Lavras, 2017.