Coffee Science
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3355
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Item Initial roasting temperature effect on thermal behaviour and characteristic of liberica coffee(Editora UFLA, 2019-10) Heriyanti; Panggabean, Yulia; Pangestu, Enggar Tyas; Asyhar, Rayandra; SutrisnoThe roasting process has brought about some changes in transition phases, in chemical characteristics, and microstructures of minerals in the Liberica coffee beans. Two initial roasting temperature variations were carried out to study the thermal behavior and characteristic of Liberica coffee, namely 200 °C and 230 °C. The thermal behaviour of phase changes of the Liberica green and ground coffee after the roasting process has been identified by using Differential Scanning Calorimeter (DSC). Chemical functional groups and molecular structures have been well-analyzed by using Fourier-Transform Infrared Spectroscopy (FTIR), Liquid Chromatography-Mass Spectrometry (LC-MS), Scanning Electron Microscope with Energy Dispersive X-Ray Spectroscopy (SEM/EDX) and X-Ray Powder Diffractions (XRD) for the green and roasted Liberica coffee. The DSC spectra indicated a high decomposition process that occurred during thermal treatment with crystallization and melting temperature around 120 °C and 325 °C for both roasting initial temperature variations, respectively. The FTIR and LC-MS are able to identify the chemical change in both the green and the roasted coffee. The dominant compounds found in the roasted Liberica coffee are caffeine, trigonelline, nicotinic acid, and dehydrocafestol. The XRD spectrum indicates that there is an amorphous phase for the green coffee and a sucrose crystal phase for the roasted coffee within the activity in 2θ = 20.3° and 21.1°.Item Quality of specialty natural coffee stored in different packages in Brazil and abroad(Editora UFLA, 2019-10) Borém, Flavio Meira; Andrade, Fabrício Teixeira; Santos, Cláudia Mendes dos; Alves, Ana Paula de Carvalho; Matias, Gabriel Carvalho; Teixeira, Daniela Edel; Ossani, Paulo César; Cirillo, Marcelo ÂngeloA challenge in the packaging and export of specialty coffees is to avoid green coffee bean storage and transport conditions that negatively affect the sensory quality of the roasted beans. The present study evaluated green beans of specialty coffees in eight types of packaging stored in a warehouse in the municipality of Poços de Caldas, Minas Gerais State, Brazil, for 18 months (Brazilian phase). This coffees were also subjected to sea transport and subsequent storage at a specialty coffee import company (export phase) in the United States, where it remained stored for 14 months. Physical, chemical, and sensory analyses of the beans were performed in the Brazilian phase and export phase. Green coffee beans stored in high-barrier packages had the best conserved quality. Packages with little or no barrier were not adequate for packaging or exporting specialty coffees. Beans in high-barrier packaging maintained their quality for long periods, which are therefore recommended for specialty coffee storage and export.Item Endocarp analysis of a traditional variety of colombian coffee(Editora UFLA, 2019-04) Muñoz, Milton; Roa, Manuel; Correa, RodrigoThis article presents the main results of thermal analytical and drying tests applied to the endocarp of coffee bean samples, in order to analyze their influence on the coffee dehydration process. An infrared analysis, as well as TGA, DTGA and DSC tests, were applied to the parchment of a sample of Castilla variety coffee beans and later compared with similar tests performed on coffee beans of the same variety, upon parchment removal. For analytical tests, the main thermogravimetric transitions are reported up to a temperature of 1000 °C. From thermograms, four temperature range were identified for parchment, with their respective mass loss: 33-33.7°C, 9.48%; 33.7-251.2°C, 16.23%; 251.2-358°C, 47.48%; and 358-800°C, 15.52%. The greatest mass loss was due to cellulose and hemicellulose degradation. The study was complemented by drying experiments on samples of beans with and without parchment. The diffusion coefficients were found using Fick’s second law and metaheuristic optimization methods (global optimization). On average, the diffusion coefficient of grains without endocarp is 46% greater than that of beans dried with the parchment. Coffee beans with parchment took, on average, 50% more time to reaching moisture levels of 12% (on dry basis). The results are considered important for the projection and design of new coffee drying systems and their automatic control.Item Control of the coffee roasting stage using artificial vision techniques(Editora UFLA, 2019-01) Sarria-González, Juan Camilo; Ivorra-Martínez, Eugenio; Girón-Hernández, JoelArtificial vision techniques were used to evaluate its application in the control of the coffee roasting stage. Coffee samples of Colombia and Castillo varieties were obtained and analyzed by comparing images during the roasting stage. A one-way ANOVA analysis exhibited 94.28% of similarity of the coffee varieties studied; a multivariate analysis showed significant differences (p<0.05) for the time factor and its interaction with the variety factor, no differences were observed (p>0.05) for the coffee varieties. Additionally, a Principal Component, with two components demonstrated 90.77% of the variance by differentiating the samples in the different roasting times. Therefore, the proposed technique could be used in the control of the coffee roasting stage.Item Determination of thermal properties of coffee beans at different degrees of roasting(Editora UFLA, 2018-10) Cardoso, Danilo Barbosa; Andrade, Ednilton Tavares de; Calderón, Renso Alfredo Aragón; Rabelo, Mariane Helena Sanches; Dias, Camila de Almeida; Lemos, Isabela ÁvilaThe aim in this study was to determine the main thermal properties of the granular mass of coffee (specific heat, thermal conductivity, and thermal diffusivity) for different degrees of roasting, as well as to model and simulate thermal conductivity at different degrees of roasting. For determination of specific heat, the mixing method was used, and for thermal conductivity, the theoretically infinite cylinder method with a central heating source. Thermal diffusivity was simulated algebraically using the results of the properties cited above and of the apparent specific mass of the product. Thermal conductivity was also simulated and optimized through finite element analysis software. As results, at darker roasting there was an increase in specific heat and a reduction in thermal conductivity and thermal diffusivity. Comparing thermal conductivity determined in relation to simulated and optimized conductivity, the mean relative error was 1.02%, on average.Item Simulation of coffee fruit drying using computational fluid dynamics(Editora UFLA, 2018-10) Amaral, Rudney; Andrade, Ednilton Tavares de; Gomes, Francisco Carlos; Borém, Flávio Meira; Lemos, Isabela Avila; Dias, Camila de AlmeidaDrying is a fundamental step in post-harvest handling of coffee because moisture content at the end of drying affects several important aspects, such as sensory quality, storability, and color of the fruit coffee. Within this context, the aim of this study is to determine water distribution within the natural coffee fruit during and at the end of the drying process. For that purpose, simulations were made through finite elements using computational fluid dynamics. Experimental data on moisture content of coffee fruit in the “cherry” stage were collected during drying, which was carried out at a temperature of 40°C and relative humidity of 25% to 0.18 decimal l(dry basis – d.b.) to compare the results of the experiment with the results of the simulations. Ten mathematical models of the drying process were developed for the collected data. The two-term exponential model best fit the data. The results of the simulations in computational fluid dynamics were compared to the results from experimental drying, and a satisfactory fit was obtained. The effective diffusivity coefficient (D eff ) was developed for the model proposed, obtaining the value of 2.87 x 10 ‐11 m 2 s -1 . At the end of drying, the model exhibited 57.1% of the projection area of the coffee fruit with moisture content below 0.18 decimal (d.b.). Thus, the model can be used for other applications.Item Relative importance and interaction of roasting variables in coffee roasting process(Editora UFLA, 2018-07) Garcia, Cinthia da Conceição; Pereira Netto, Annibal Duarte; Silva, Michelle Costa da; Catão, Alexandre Alves; Souza, Iasmim Amorim de; Farias, Larissa Silva; Paula, Thiago Nunes Emerich de; Paula, Mateus Nunes Emerick de; Reis, Sandro Coutinho dos; Silva Junior, Ademário Iris daThis work describes a study in which levels of variables that may control the coffee roasting process were set in an experimental matrix that aimed at measuring their relative importance and the interaction between variables. Each control variable was set in two levels and the combination of these levels elicited 32 different roasting procedures. The physical responses were determined for a specific roaster. Experimental planning allowed the determination of the relative influence of each control variable in each response variable for this roaster. This led to a primary quantification of the major factors that contribute to the roasting process and the relative importance of roast parameters that influence the quality of the coffee beverage. Moreover, these results indicated what interactions could occur between these parameters. The characterization of the relative influence of control variables is a first approach to model the roaster response and the coffee quality that each roasting can achieve.Item Contribution of agronomic traits to the coffee yield of Coffea canephora Pierre ex A. Froehner in the western amazon region(Editora UFLA, 2018-07) Spinelli, Victor Mouzinho; Moraes, Marcos Santana; Alves, Darlan Sanches Barbosa; Rocha, Rodrigo Barros; Ramalho, André Rostand; Teixeira, Alexsandro LaraThe evaluation of morphological characters related to the hulled coffee yield subsidizes the selection of Coffea canephora plants that combine a set of favorable traits. The aim of this study was to evaluate the direct and indirect effects of agronomic traits on the production of hulled coffee to subside the plant selection. To this, nine morphological descriptors were evaluated of 130 clones of the botanical varieties Conilon and Robusta over two crop years in the experimental field of Embrapa, in the municipality of Ouro Preto do Oeste, state of Rondônia (RO). To quantify the genetic variability the path analysis and the Scott Knott cluster test were used. The effect of genotype x year interaction was significant for eight of the nine characteristics analyzed. The genotypes were clustered in three to five classes, subsidizing the establishment of a scale to evaluate the variability of this genetic resource. Pathway analysis indicated that the number of plagiotropic branches and the number of rosettes per productive branch were the traits that exhibited the greatest direct effect on hulled coffee yield. These results show that it is possible to select plants with complementarity traits which favor a higher production of hulled coffee.Item Competitive pressures on the artisan coffee roaster segment in the state of Minas Gerais, Brazil: a multi-case study(Editora UFLA, 2018-04) Guimarães, Elisa Reis; Andrade, Helga Cristina Carvalho de; Cozadi, Álvaro dos Reis; Antonialli, Luiz Marcelo; Santos, Antônio Carlos dosThe specialty coffee market is still little known and underexplored in Brazil, motivating an analysis of the competitive pressures and structure of the artisan coffee roaster segment in the state of Minas Gerais, in order to better understand it and encourage the adoption of specific policies for its expansion, besides comparing it to the commodity coffee roasting segment. A multi-case study was performed with three companies in this segment through in-depth interviews with their owners. There were significant changes in the competitive forces that shape the coffee industry, when comparing the specialty and commodity coffee segments, both in intensity and in motivations. Among the suggested policies to support the specialty coffee segment are its promotion and dissemination through “consumer education” and awareness raising on the differentiated properties of these products, besides providing subsidized courses and specializations for those who wish to be involved in this marketplace.Item Quality of natural coffee dried under different temperatures and drying rates(Editora UFLA, 2018-04) Borém, Flávio Meira; Isquierdo, Eder Pedroza; Alves, Guilherme Euripedes; Ribeiro, Diego Egídio; Siqueira, Valdiney Cambuy; Taveira, Jose Henrique da SilvaThe final quality of coffees depends on the preservation of the cell membranes of the coffee beans, which can be damaged during the drying. Thus, the aim of this study was to assess the immediate and latent effects of the air temperature and drying rate on the sensorial quality of natural coffees, as well as its relationship with the chemical e physiological characteristics of the coffee beans. Mature fruits of arabica coffee were harvested and sundried to moisture content of approximately 35% (wb) and then moved into a mechanical drier under different conditions of drying. This process involved the combination of three dry bulb temperatures – DBT (35°C, 40°C, and 45°C) and two dew point temperatures – DPT (2.6°C and 16.2°C). Thus, the relative humidity of the air used for drying was a dependent variable of DTB and DPT, and as consequences, different drying rates were achieved for each DBT. The increase in the drying rate for the temperatures 35°C and 40°C has a negative effect on the final quality of natural coffee beans. However, for the temperature of 45°C, the effects of the drying rate on the coffee beans are overlaid by the thermal damages that are caused at this level of heating. Higher sensory scores for coffee are linked to lower values of electrical conductivity and potassium leaching of the exudate of the coffee beans, as well as lower values of fatty acids. It is emphasized that while the temperature of 35o C is recommended for the production of specialty coffees the temperature of 45o C is not.