Coffee Science (E-Journal)
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Microorganisms in coffee fermentation: A bibliometric and systematic literature network analysis related to agriculture and beverage quality (1965-2019)
Get PDFThe activity of microorganisms in coffee fermentation has a great influence on the composition of the beans and their beverage quality. In the present study a bibliometric and systematic literature network analysis is made to examine the growth in the literature and the flow of knowledge in the field of study. The bibliometric information was retrieved from the Scopus database, obtaining 55 articles between 1965 and 2019. Frequencies, co-authorship, and co-occurrence The activity of microorganisms in coffee fermentation has a great influence on the composition of the beans and their beverage quality. In the present study, a bibliometric and systematic literature network analysis is made to examine the growth in the literature and the flow of knowledge in the field of study. The bibliometric information was retrieved from the Scopus database, obtaining 55 articles between 1965 and 2019. Frequencies, co-authorship, and co-occurrence indicators were analyzed using Microsoft Excel and VOSviewer software. Our findings show that most of the articles have been published in the last decade and mainly on microbial diversity and starter cultures. Furthermore, it was possible to identify the most productive authors, the most influential works, the main journals where articles of the most productive authors and the most influential works have been published, the most productive affiliation countries, the most used keywords, the co-authorship taking authors and countries as the unit of analysis, the keyword co-occurrence, and the spatial distribution of studies with their research topics. This is the first bibliometric and systematic literature network analysis carried out on research articles on microorganisms in coffee fermentation related to agriculture and beverage quality, which becomes a tool for researchers in making decisions for the building and development of strategic plans for future research by understanding the trends and status of existing research in the field of study in accordance with the authors, works, affiliation countries, study topics, and patterns of international collaboration and within the academiccommunity.
Key words: Bibliometry; Coffea; coffee processing; cup quality; microbiology
Unsupervised classification of specialty coffees in Homogeneous sensory attributes through machine learning
Get PDFBrazil is the largest exporter of coffee beans, 29% world exports, 15% this volume in specialty coffees. Thereby researches are done, so that identify different segments in the market, in order to direct the end consumer to a better quality product. New technologies are explored to meet an increasing demand for high quality coffees. Therefore, in this article has an objective to propose the use of machine learning techniques combined with projection pursuit in the construction of unsupervised classification models, in a sensory acceptance experiment, applied to four groups of trained and untrained consumers, in four classes of specialty coffees in which they were evaluated sensory characteristics: aroma, body coffee, sweetness and general note. For evaluating classifier performance, in the data with reduced dimension, all instances were used, and considering four groupings, the models were adjusted. The results obtained from the groupings formed were compared with pre-established classes to confirm the model. Success and error rates were obtained, considering the rate of false positives and false negatives, sensitivity and classification methods accuracy. It was concluded that, machine learning use in data with reduced dimensions is feasible, as it allows unsupervised classification of specialty coffees, produced at different altitudes and processes, considering the heterogeneity among consumers involved in sensory analysis, and the high homogeneity of sensory attributes among the analyzed classes, obtaining good hit rates in some classifiers.
Key words: Classification models; Data dimension reduction; Groupings identification; Projection pursuit
APPLICATIONS OF COPPER-BASED FUNGICIDES AND INFESTATIONS OF Leucoptera coffeella (Guérin-Mèneville & Perrottet) IN COFFEE PLANTS
Get PDFThe present study aimed to evaluate the effects of applying fungicides with different sources of copper and of the number of applications on the occurrence of Leucoptera coffeella (Guérin-Menéville & Perrottet, 1842) (Lepidoptera: Lyonetiidae) and on the wax layer on leaves in a coffee plantation. Four applications of fungicides were carried out and the effects on the number of leaves mined by the insect and on the wax content on the leaf surface were evaluated. The copper-based fungicides increased the number of leaves mined by the leaf-miner and reduced the wax content on the coffee leaf surfaces in both periods studied
TOPOCLIMATIC CHARACTERIZATION OF SPECIALTY COFFEES FROM MANTIQUEIRA REGION IN MINAS GERAIS
No full textThe objective of this study was to identify meteorological variables related to the sensorial quality of the coffees from Mantiqueira region in Minas Gerais. Meteorological conditions are strongly related to the coffee’s sensorial characteristics, however, there aren’t many studies quantifying this relation. Air temperature and rainfall data were collected and spatialized for regional analysis. These were associated to the 2007 through 2011 coffees’ beverage scores. The region is stratified according to relief characteristics. The bigger frequency of high scores occurred on the region’s central-south, where coffee cultivation is performed above 900 m altitude. For the in loco study, meteorological data and coffee samples were collected in selected pilot areas. Coffee crops were selected in three altitude ranges: below 1000 m, between 1000 and 1200 m, and over 1200 m. Above 1000 m the meteorological variable that presented the biggest variation was the air temperature. Above 1000 m the smallest thermal amplitude occurred, which provided superior quality coffees. The study demonstrates the importance of the meteorological variable characterization aiming to identify locations with greater vocation to the specialty coffees production.This study’s purpose was to identify topoclimatic variables related to the sensorial quality of the coffees from Mantiqueira region in Minas Gerais. Topoclimatic conditions are strongly related to the coffee’s sensorial characteristics, however, there aren’t many studies quantifying this relation. Air temperature and precipitation data were collected and spatialized for regional analysis. These were associated to the 2007 through 2011 coffees’ drink grades. The region is stratified according to topoclimatic characteristics. The bigger frequency of high grades occurred on the region’s central-south cities, where coffee cultivation is performed above 900 m altitude. For the in loco study, meteorological data and coffee samples were collected in selected pilot areas. Coffee crops were selected in three altitude ranges: below 1000 m, between 1000 and 1200 m, and over 1200 m. Above 1000 m the meteorological variable that presented the biggest variation was the air temperature. Above 1000 m the smallest thermal amplitude occurred, which provided superior quality coffees. The study demonstrates the importance of the topoclimatic characterization aiming to identify locations with greater vocation to the specialty coffees production.
MODELING DYNAMIC ADSORPTION ISOTHERMS AND THERMODYNAMIC PROPERTIES OF SPECIALTY GROUND ROASTED-COFFEE (Coffee Arabica L.)
Get PDFSpecialty coffee is highly differentiated product because of its sensorial attributes: aroma, body and brand reputation. In specialized markets, these products are highly valued, and sometimes up to six times their commercial value is paid. Thus, it is essential to preserve their freshness. Sorption isotherms are necessary for determining and studying water sorption changes in specialty coffee during storage. This study aimed to determine the adsorption isotherms of specialty ground roasted-coffee at temperatures of 25 °C, 30 °C and 40 °C and water activities between 0.1 and 0.8 using the dynamic dewpoint method (DDI). The experiment sorption data were modeled using 12 different equations with non-linear regression to represent the dependence of the equilibrium moisture content with both water activity and temperature. In addition, the thermodynamic properties were determined with the experiment adsorption data. The results showed that type III isotherms were obtained according to the Brunauer classification, and the Weibull equation satisfactorily modeled the effect of the temperature on the hygroscopic equilibrium in the specialty ground roasted-coffee. The results of thermodynamic analysis showed that the net isosteric heat of adsorption and Gibbs free energy decreased as the equilibrium moisture content increased, indicating the amount of energy released, a strong bond energy between water molecules in the product components and spontaneity in the adsorption process. The entropy of the adsorption increased with the moisture content, leading to product stability conditions during storage. The results were similar to those reported for the roasted and ground coffee of others cultivars
SELECTION OF COFFEE PROGÊNIES FOR RESISTANCE TO LEAF RUST AND FAVORABLE AGRONOMIC TRAITS
Get PDFThe objective of this study was to select coffee progenies with better assessment that can result in coffee rust resistant cultivars and better agronomic characteristics than the traditional ones. The essay was performed at the EPAMIG experimental field in Patrocínio, state of Minas Gerais, Brazil. Twenty-five progenies in the F3 generation were studied. The experiment was set in a randomized complete block design with three replicates and ten plants per plot, arranged in rows at 3.5x0.7m. Productivity assessment, fruit production, in liters of “farm coffee” per plot, bean rating in a sieve (16 or above), and plant vigor were accessed in three different harvest seasons (2011/2012 harvest to 2014/2015 harvest), and coffee rust incidence and severity were then evaluated for 2016. The production profit estimation through the selection was also assessed, by the gain of direct selection for each characteristic, when compared to the rank addition. Progenies 13 (Icatu V. IAC 4040 x IAC 5002) and 3 (Icatu A. IAC 2944 x IAC 5002) were promising in generation advance, for being among the five most productive progenies. The selection gain reached by direct selection was superior than the gain of the total rank additions
ENDOCARP ANALYSIS OF A TRADITIONAL VARIETY OF COLOMBIAN COFFEE
Get PDF This 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.
THE OCCURRENCE OF CAFESTOL AND KAHWEOL DITERPENES IN DIFFERENT COFFEE BREWS
Get PDFCoffee is the second most consumed brew in the world, after water. Cafestol and kahweol are two diterpenes that have been identified, until now, exclusively in the coffee tree. They are co-extracted from the coffee beans that are roasted and ground for the beverage preparation. Their pharmacological properties are related to anticancer and anti-inflammatory activities, although they also increase the serum cholesterol. Several researches reported that coffee brew preparation methods influence directly the levels of the diterpenes. This paper describes a compilation of the main results published for different coffee brews and all variables related to their preparation. Major differences in the reported concentrations have been noted
SENSORY PROFILE OF ARABICA COFFEE ACCESSES OF THE GERMPLASM COLLECTION OF MINAS GERAIS – BRAZIL
Get PDFThis study was developed to determine the beverage quality and the sensory profile of Coffea arabica accesses of the Germplasm Collection of Minas Gerais State in two consecutive harvests. Mature coffee fruits from 49 accesses were selectively harvested in the 2015 and 2016 harvests, and after processing and drying they were sensorially evaluated by a team of trained judges in accordance to the protocols of the Specialty Coffee Association. The data were analyzed by Principal Component Analysis, Cluster Hierarchical Analysis, and Content Analysis. The year of harvest influences the scores of the sensory attributes of the beverage of some coffee accesses. The access 27 (Pacamara) stood out with the highest sensory score seen in the first year of harvest. The accesses 36 (Timor Hybrid UFV376-52) and 43 (BE5 WushWush) stood out for the final sensory score in the two years of evaluation. All accesses belonging to the Timor Hybrid Germplasm stood out in the beverage quality in the second year of harvest. A total of 139 sensory attribute descriptors were identified, and the content analysis showed different levels for the frequency of terms in each access group formed as a function of quality. The Germplasm Collection of Minas Gerais has a wide variability for the production of superior quality coffees, and the year of harvest influences to a greater or lesser degree the potential of quality of the accesses
CONTROL OF THE COFFEE ROASTING STAGE USING ARTIFICIAL VISION TECHNIQUES
Get PDFArtificial 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