Biblioteca do Café

URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/1

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2020 - 20212

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Autor: search.filters.author.Gutiérrez-Guzmán, NelsonAssunto: search.filters.subject.Colheita, pós-colheita e armazenamento

Resultados da Pesquisa

Agora exibindo 1 - 2 de 2
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    ATR-FTIR for characterizing and differentiating dried and ground coffee cherry pulp of different varieties (Coffea arabica L.)
    (Associação Brasileira de Engenharia Agrícola, 2021) Barrios-Rodríguez, Yeison; Collazos-Escobar, Gentil A.; Gutiérrez-Guzmán, Nelson
    This study aimed to evaluate the performance of the infrared spectrum in the range of 4000−650 cm−1 for characterizing and differentiating dried and ground coffee cherry pulp of different varieties. The spectral data were subjected to first and second derivative treatments to perform the statistical analyses. Three varieties of coffee pulp were previously characterized for color, water activity, moisture, chlorogenic acids, and caffeine. The results of principal component analysis (PCA) showed that Fourier transform infrared (FTIR) spectroscopy is a viable technique for characterizing and differentiating dried and ground coffee cherry pulp among different varieties, showing the best differentiation with treatment of data from the first derivative, which was mainly associated with the caffeine content and chlorogenic acids. This study is the first investigation of FTIR spectroscopy with attenuated total reflectance for characterizing dried and ground coffee cherry pulp from coffee varieties grown in Colombia.
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    Moisture dynamic sorption isotherms and thermodynamic properties of parchment specialty coffee (Coffea arabica L.)
    (Editora UFLA, 2020) Collazos-Escobar, Gentil Andres; Gutiérrez-Guzmán, Nelson; Váquiro-Herrera, Henry Alexander; Amorocho-Cruz, Claudia Milena
    Sorption isotherms represent an efficient and valuable tool for predicting the equilibrium moisture content of foods under different humidities and temperatures; thus, they are useful for determining shelf-life and safe storage conditions. The aims of this study were to determine the sorption isotherms of parchment specialty coffee at water activity values of 0.1−0.8 and temperatures of 25, 30, and 40 °C using the dynamic dew point method. The experimental sorption data were modeled using 12 different equations to represent the dependence of equilibrium moisture content on water activity and temperature. Thermodynamic properties were also obtained from the experimental data. The results showed a type II sigmoid shape according to Brunauer-Emmett-Teller (BET) classification, and the double log polynomial (DLP) equation successfully modeled the effects of temperature on the sorption isotherms, obtaining a good fit (R2 adj = 0.99 and RMSE = 0.1 % dry basis). The dynamic dewpoint isotherm (DDI) method was advantageous for modelling due to its high availability of experimental data. Thermodynamic analyses showed that the net isosteric heat of sorption, Gibbs free energy, and sorption entropy decreased as equilibrium moisture content increased, and the compensation theory provided evidence that the sorption process was controlled by enthalpy (Tβ > Thm).