Intensidade do potencial osmótico no controle da embriogênese somática direta em cafeeiro

The objective of this work was to characterize the effect of the osmotic potential of the culture medium on the control of direct somatic embryogenesis in coffee (Coffea arabica) tree. Leaf explants of the Mundo Novo cultivar and four hybrids were subjected to the direct route in the presence of polyethylene glycol 6000, at the following concentrations: 0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0%. Embryogenic structures and somatic embryos were formed at a threshold osmotic potential of up to -0.691 and -0.374 MPa, respectively, with a reduction or inhibition in these responses under a more negative osmotic potential.O objetivo deste trabalho foi caracterizar o efeito do potencial osmótico do meio de cultura no controle da embriogênese somática direta em cafeeiro (Coffea arabica). Explantes foliares da cultivar Mundo Novo e de quatro híbridos foram submetidos à via direta na presença de polietilenoglicol 6000, nas seguintes concentrações: 0, 2,5, 5,0, 7,5, 10,0, 12,5 e 15,0%. Estruturas embriogênicas e embriões somáticos formaram-se no potencial osmótico limite de até -0,691 e -0,374 MPa, respectivamente, com redução ou inibição destas respostas nos potenciais osmóticos mais negativos

Sensory analysis and chemical composition of ‘bourbon’ coffees cultivated in different environments

Given the growing participation and appreciation of specialty coffees in the international market, coupled to the intrinsic quality of cultivar Bourbon for the production of differentiated coffees and the environmental diversity of Brazil, this study was conducted, with the objective to evaluate how the interaction between ‘Bourbon’ genotypes and different environments affect the sensory quality of coffees, besides relating the chemical composition (trigoneline, 5-CQA and caffeine) of beans with their sensory profile. Four Arabica coffee genotypes were evaluated: one of them is widely grown in Brazil (Mundo Novo) and three belong to the group of cultivar Bourbon. The genotypes were evaluated in a field experiment, in Lavras, MG; Santo Antônio do Amparo, MG and São Sebastião da Grama, SP. Thelatter was the most promising environment for the production of specialty coffees. Genotypes Yellow Bourbon IAC J9 and Yellow Bourbon/SSP were the most suitable for the production of specialty coffees. Regardless of culture environment, the genotype Yellow Bourbon/CM is not suitable for the production of specialty coffees. Caffeine content enabled coffee differentiation regarding beverage quality. Coffees with superior quality have lower caffeine contents. The content of 5-CQAallowed to differentiate environments

Protein profiles and physiological performance of coffee seeds subjected to different processing and drying methods

O objetivo deste trabalho foi avaliar os perfis proteicos e o desempenho fisiológico de sementes de café submetidas a diferentes métodos de processamento e secagem. Foram avaliados os processamentos por via seca e úmida, e as secagens natural, em terreiro, e artificial a 60ºC, ou a 60ºC até 30% de umidade e 40ºC até teor final de 11% (base úmida). Após serem processadas e secadas, as sementes foram avaliadas quanto ao desempenho fisiológico e submetidas a análises bioquímicas, por meio da eletroforese de proteínas resistentes ao calor LEA (“late embryogenesis abundant”) e das enzimas superóxido dismutase, catalase, peroxidase, esterase, polifenoloxidase, isocitrato desidrogenase, álcool desidrogenase e malato desidrogenase. O perfil proteico de sementes de café é afetado pelo método de processamento e de secagem. Os cafés processados por via úmida apresentam maior tolerância à secagem – revelada pela maior atividade de enzimas antioxidativas e pelo melhor desempenho fisiológico – do que os processados por via seca. A atividade de proteínas resistentes ao calor e de enzimas antioxidantes é variável promissora para diferenciar a qualidade dos cafés submetidos a diferentes manejos pós‑colheita.The objective of this work was to evaluate the protein profiles and physiological performance of coffee seeds subjected to different drying and processing methods. We evaluated processing by dry and wet routes, the drying methods: natural, on the patio, and artificial at 60ºC, or at 60ºC until 30% of moisture content and 40ºC until 11% (wet basis). After processing and drying, the seeds were evaluated as to their physiological performance and subjected to biochemical analyses with electrophoresis of heat‑resistant LEA (late embryogenesis abundant) proteins and of the enzymes superoxide dismutase, catalase, peroxidase, esterase, polyphenol oxidase, isocitrate dehydrogenase, alcohol dehydrogenase, and malate dehydrogenase. The protein profile of coffee seeds is affected by the processing and drying methods. The coffee processed by wet route has higher tolerance to drying – shown by the higher activity of antioxidative enzymes and better physiological performance – than that processed by dry route. The activity of heat‑resistant proteins and antioxidant enzymes is a promising variable for the differentiation of the quality of coffee subjected to different postharvest management

Population density of Arabica coffee cultivars for bean quality and yield

For the implantation of a coffee tree crop, aiming at a high yield, each cultivar, depending on the plant distribution and density, can express differently its results. This study aimed to evaluate the yield potential and grain quality of Arabica coffee cultivars grown under different spacings between rows and between plants. A randomized block design was used, with three replications, in a split-split-plot scheme, being the plots three coffee cultivars (Obatã IAC-1669-20, Tupi IAC-1669-33 and Catuaí Vermelho IAC-144), four spacings between rows (1.8 m, 2.0 m, 2.5 m and 3.0 m) and four spacings between plants in the row (0.5 m, 0.7 m, 0.8 m and 1.0 m), totaling 48 treatments. The type of coffee bean (flat, peaberry and elephant) and yield per hectare were evaluated. The Obatã cultivar showed the highest potential yield, in relation to Tupi and Catuaí Vermelho, and also the highest percentage of flat grains. The factors, in order of importance, that interfere with the potential yield of processed coffee are the cultivar and the spacing between rows and between plants

Aspectos fisiológicos de grãos de café, processados e secados de diferentes métodos, associados à qualidade sensorial

The objective of the present study was to evaluate the physiological and sensory quality of coffee beans processed and dried in different manners. The experiment was conducted with two types of processing - dry and wet processing, and four drying methods - drying in a drying yard, and mechanical drying with heated air at three alternating temperatures (50/40°C, 60/40°C and 40/60°C) where the temperature was changed when the coffee beans reached moisture content of 30%± 2% (w.b.), with supplementation of drying until achieveing 11% ± 1% (w.b.). The mechanical drying system used consisted of three fixed bed dryers, which allows control of temperature and flow drying rate. After application of the treatments, the coffees were sampled according to the evaluation system proposed by the Specialty Coffee Association of America (SCAA). In addition to sensory analysis, analyses were made of the physical-chemical and physiological quality of the coffee beans. Thephysical-chemical and physiological analyses involved: fatty acid composition, leaching of potassium, electrical conductivity and germination. Interesting results were obtained. Coffee dried in the drying yard showed better sensory, physiological and physical-chemical results when compared with that dried in a dryer. Pulped coffee was more tolerant to drying than natural coffee, regardless of the way it was dried, showing better final quality of the product. Moreover, it may be observed that the increase in drying temperature in the final phase of the drying process leads to grain damage, which notably reduces beveragequality, confirming existing research.Objetivou-se, no presente trabalho, avaliar a qualidade sensorial e fisiológica dos grãos de café processados e secados de diferentes formas. O experimento foi realizado com dois tipos de processamento: via seca e via úmida; e quatro métodos de secagem: secagem em terreiro, e secagem mecânica com ar aquecido em temperaturas alternadas: 50/40°C, 60/40°C e 40/60ºC, onde a temperatura foi alterada quando os grãos de café atingiram teor de água de 30 % ± 2 % (b.u.), com complementação da secagem até atingir 11%±1% (b.u.). O sistema mecânico de secagem utilizado constituiu-se de três secadores de camada fixa, o qual permite o controle da temperatura e fluxo de secagem. Após a aplicação dos tratamentos, oscafés foram degustados segundo o sistema de avaliação proposto pela Associação Americana de Cafés Especiais (SCAA). Além da análise sensorial foram feitas as análises da composição físico-química e qualidade fisiológica dos grãos de café. As análises físico-químicas e fisiológicas envolveram: acidez graxa, lixiviação de potássio, condutividade elétrica e germinação. Foram obtidos resultados interessantes. Os café secados em terreiro apresentaram os melhores resultados sensoriais, fisiológicos e físico-químicos, quando comparados com os secados em secador. O café despolpado foi mais tolerante à secagem do que o café natural, independente da forma com foi secado, apresentando melhor qualidade final do produto. Pode-se observar ainda que a elevação da temperatura de secagem, na fase final do processo de secagem, promove danos aos grãos, os quais reduzemsensivelmente a qualidade da bebida, confirmando pesquisas já existentes

Microscopia eletrônica de varredura de grâos de café submetidos a diferentes formas de processamento e secagem

The objective of the present work was to evaluate changes in the structure of coffee beans processed and dried in different ways. The experiment was conducted with two types of processing: dry and wet, and four drying methods: drying on ground and mechanical drying with air heated to 50/40 ° C, 60/40 ° C and 40/60 ° C, where the temperature was changed when the coffee beans reached 30% ± 2% (db), with supplementation of dehydrated to 11% ± 1% (wb). The mechanical drying system used consisted of three fixed bed dryers, which allows control of temperature and flow rate of drying. During the experiment,data were collected to assess the dynamics of drying.After treatment application, the coffee beans were subjected to studies in a scanning electron microscope (SEM). The observation of the coffee beans by SEM showed that the drying temperature of 50/40 ° C pulped coffees showed similar results to those dried in cafes, with a small contraction of the cells, without signs of rupture. It was observed that utilization of the drying temperature 40/60 ° C was the most damage caused to the structures of cells, regardless of the type of processing. It was found that the coffee prepared by dry showed higher destruction of the cellularcomponents of the coffee pulped and, a longer exposure of coffee to the drying process.Objetivou-se, no presente trabalho, avaliar alterações na estrutura de grãos de café processados e secados de diferentes formas. O experimento foi realizado com dois tipos de processamento: via seca e via úmida; e quatro métodos de secagem: secagem em terreiro, e secagem mecânica com ar aquecido a 50/40°C, 60/40°C e 40/60ºC, onde a temperatura foi alterada quando os grãos de café atingiram 30%±2% (b.u.), com complementação da secagem até atingir 11%±1% (b.u.). O sistema mecânico de secagem utilizado constituiu-se de três secadores de camada fixa, o qual permite o controle da temperatura e fluxo de secagem. Durante o experimento foram coletados dados para a avaliação da dinâmica de secagem. Após a aplicação dos tratamentos, os grãos de cafés foram submetidos a estudos em microscópio eletrônico de varredura (MEV). A observação dos grãos de café em MEV mostrou que a temperatura de secagem de 50/40°C dos cafés despolpados apresentou resultados semelhantes aos cafés secados em terreiro, com pequena contração das células, sem sinais evidentes de ruptura. Pôde-se observar também que a utilização da temperatura de secagem 40/60°C foi a que mais causou danos às estruturas dascélulas, independentemente do tipo de processamento. Verificou-se que os cafés preparados por via seca apresentaram maior desestruturação dos componentes celulares do que os cafés despolpados, bem como maior tempo de exposição desses cafés ao processo de secagem