Navegando por Autor "Melo, Evandro de C."

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Determination of the influence of the variation of reducing and non-reducing sugars on coffee quality with use of artificial neural network
(Associação Brasileira de Engenharia Agrícola, 2012-03) Messias, José A. T.; Melo, Evandro de C.; Lacerda Filho, Adílio F. de; Braga, José L.; Cecon, Paulo R.
The present study aimed at evaluating the use of Artificial Neural Network to correlate the values resulting from chemical analyses of samples of coffee with the values of their sensory analyses. The coffee samples used were from the Coffea arabica L., cultivars Acaiá do Cerrado, Topázio, Acaiá 474-19 and Bourbon, collected in the southern region of the state of Minas Gerais. The chemical analyses were carried out for reducing and non-reducing sugars. The quality of the beverage was evaluated by sensory analysis. The Artificial Neural Network method used values from chemical analyses as input variables and values from sensory analysis as output values. The multiple linear regression of sensory analysis values, according to the values from chemical analyses, presented a determination coefficient of 0.3106, while the Artificial Neural Network achieved a level of 80.00% of success in the classification of values from the sensory analysis.
Kinetics of mass loss of arabica coffee during roasting process
(Associação Brasileira de Engenharia Agrícola, 2016-03) Vargas-Elías, Guillermo A.; Corrêa, Paulo C.; Souza, Natália R. de; Baptestini, Fernanda M.; Melo, Evandro de C.
Roasting is one of the most complex coffee processing steps due to simultaneous transfers of heat and mass. During this process, beans lose mass because of fast physical and chemical changes that will set color and flavor of the commercial coffee beverage. Therefore, we aimed at assessing the kinetics of mass loss in commercially roasted coffee beans according to heating throughout the processing. For that, we used samples of 350-g Arabica coffee processed grains with water content of 0.1217 kg a kg-1 , in addition to a continuous roaster with firing gas. The roaster had initial temperatures of 285, 325, 345 and 380 °C, decreasing during the process up to 255, 285, 305 and 335 °C respectively. Mass loss was calculated by the difference between grain weight before and after roasting. We observed a linear variation directly dependent on roaster temperature. For each temperature during the process was obtained a constant mass loss rate, which was reported by the Arrhenius model with r 2 above 0.98. In a roaster in non-isothermal conditions, the required activation energy to start the mass loss in a commercial coffee roasting index was 52.27 kJ mol-1 .
Quality of coffee beans from peeled green fruits after temporary immersion in water
(Departamento de Engenharia Agrícola - UFCG, 2020) Coelho, Ana P. de F.; Silva, Juarez de S. e; Carneiro, Antônio P. S.; Melo, Evandro de C.; Silva, Camilla S. da; Lisboa, Cristiane F.
The harvest of green coffee fruits affects their quality; they should be separated from the ripe fruits during processing. The proportion of harvested green fruits can be high, requiring information and technologies to adequately manage and add value to coffee beans from this fruit category. The objective of this work was to evaluate the quality of coffee beans from green fruits separated during a wet processing and peeled after temporary immersion in water. A completely randomized design was used, consisting of six treatments (ripe peeled coffee fruits dried on suspended yards, non-peeled green coffee fruits under traditional dry management on a concrete yard, and peeled and non-peeled green coffee fruits temporarily immersed in water and dried on suspended and concrete yards) and four replications, in the 2018 crop season. Samples of coffee beans temporarily immersed in water were peeled and separated into peeled and non-peeled fractions and dried in suspended and concrete yards. The peeling yield of green coffee beans and the physical and sensorial characteristics of the processed coffee beans were evaluated. The mean peeling yield was 62% and allowed the separation of more developed green fruits, equating them to ripe peeled coffee beans regarding physical and sensorial quality.