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    Optimization of the roasting conditions of arabica coffee cultivated in the cerrado area of Brazi
    (Instituto de Tecnologia de Alimentos – ITAL, 2018) Malaquias, Juaci Vitória; Celestino, Sonia Maria Costa; Xavier, Manaira Ferreira Franco
    The aim of this work was to optimize, by way of a rotational central composite design (RCCD), the roasting temperature and time conditions of beans from three Coffea arabica L. genotypes cultivated in the Cerrado, Brazil under controlled water stress conditions, to maintain a high soluble solids content and a roasting colour acceptable by consumers. In this way it will be possible to know the potential use of these genotypes in the instant coffee industry. The RCCD design was carried out with 2 factors (time and temperature) and 11 experiments for each of the three genotypes. The soluble solids contents were determined using a digital refractometer and the roasted bean colour evaluated using the Agtron system. The software R was used in both the variance analysis and in the multiple linear regression to define the prediction mathematical models and the statistical parameters. The Excel SOLVER tool version 2010 was used to select the best colour-soluble solids binomial to provide a colour from 65# to 45# (medium light to moderately dark) on the Agtron system and the highest soluble solids value. The roasting temperature and time conditions that maintained high soluble solids contents and produced roasted beans with an appropriate colour for consumption were 204.8 °C and 10.9 minutes for the cultivar MG 1177; 214.2 °C and 8.8 minutes for MG 0188; and 240 °C and 7 minutes for Icatu 2944, showing the potential for traditional consumption and the production of instant coffee.
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    Spray drying of coffee leaf extract
    (Editora UFLA, 2016-07) Corrêa, Jefferson Luiz Gomes; Mendonça, Kamilla Soares de; Rodrigues, Leonardo Reis; Resende, Mário Lúcio Vilela; Alves, Guilherme Eurípedes
    The coffee leaf extract formulation has been used as resistance inductor in plants and to control phytopathologies. This work aimed to study the influence of spray drying process variables with the use of maltodextrin as carrier on the characteristics of the powder, by using a central composite rotational design (CCRD). The independent variables were maltodextrin concentration (X 1 , 0 to 30 % w/v), coffee leaf extract concentration (X 2 , 2 to 32 % w/v), inlet air temperature (X 3 , 180 to 250 °C) and air flow rate (X 4 , 3.5 to 5.5 m 3 min -1 ). The response variables were collection efficiency (h) , moisture content (MC), phenolic compounds content (Ph), soluble solids (S) content, wettability (We) and particle size (Me). The results showed that the combination of a higher concentrations of coffee leaf extract (X 2) (32%) and lower inlet air temperatures (X 3 ) (180°C) make the best drying performance. This process condition lead to a powder with higher Ph, S, We, Me and lower MC. Therefore, the use of high air flow rates (X 4 ) increase the collection efficiency (h) of process and the use of low maltodextrin concentration (X 1 ) lead to better preservation of phenolic compounds content (Ph) on coffee leaf extract powdered.