Water adsorption isotherms of coffee blends / Isotermas de adsorção de água em blends de café

Gabriel Henrique Horta de Oliveira, Ana Paula Lelis Rodrigues de Oliveira, Magno Vinicius Corrêa de Souza, Ramon Felipe Neves, Fernando Mendes Botelho, Silvia de Carvalho Campos Botelho

Abstract


This work aimed to evaluate the adsorption isotherms of roasted and grinded coffee, in different blends and storage temperatures. Crude grain coffee of two species were used: arabica (Coffea arabica) and robusta(Coffeacanephora), dehulled and dried. Grain were submitted to a selection to eliminate deteriorated grain, damaged and bored, to obtain a homogeneous raw material, without defects. Grain coffee from both species, after triage, were sent to roasting process at medium light level (Agtron SCAA#65).After roasting process, grain wasprocessed in a Mahlkönig mill, at average particle size (0.84 m). Blends were made in the following proportions of arabica and robusta: 80:20; 60:40 and 40:60.Samples were stored in BOD chambers for 6 months and kept at temperatures of 10 and 30 ºC, with initial moisture content of 2.0 ± 0.3 % (d.b.). At the beginning of storage (time zero) and at 30, 60, 120 and 180 days of storage, moisture content and water activity were determined. Several mathematical models, frequently used to represent the agricultural products hygroscopicity, were fitted to experimental data of sorption. Values of water activity and moisture content varied between 0.1912 and 0.5160; 2.20 and 5.51 % (d.b.), respectively. Modified Oswin model was the one that best represented the adsorption of coffee blends.

 

 


Keywords


mathematical modeling, moisture content, water activity

Full Text:

PDF

References


Associação Brasileira da Indústria de Café - ABIC. Indicadores da Indústria de Café. Disponível em: https://www.abic.com.br/estatisticas/indicadores-da-industria/. Acessoem: 08/04/2020.

BAPTESTINI, F. M.; CORRÊA, P. C.; OLIVEIRA, G. H. H.; CECON, P. R.; SOARES, N. F. F. Kinetic modeling of water sorption by roasted and ground coffee. Acta Scientiarum. Agronomy, v.39, n.3, p.273-281, 2017.

BOTELHO, F. M.; CORRÊA, P. C.; BOTELHO, S. C. C.; VARGAS-ELÍAS, G. A.; DINIZ, M. D. M. S.; OLIVEIRA, G. H. H. Propriedades físicas de frutos de café robusta durante a secagem: Determinação e modelagem. Coffee Science, v.11, p.65-75, 2016.

BRASIL. Regras para análise de sementes.Brasília:Ministério da Agricultura e Reforma Agrária, Secretaria Nacional de defesa Agropecuária, 2009.

BRUNAUER, S. The Adsorption of Gases and Vapors.Princeton: Princeton University Press, 1945.

CORRÊA, P.C.; BOTELHO, F.M.; BOTELHO, S.C.C.; GONELI, A.L.D. Isotermas de sorção de água de frutos de Coffeacanephora. Revista Brasileira de Engenharia Agrícola e Ambiental, v.18, p.1047-1052, 2014.

CORRÊA, P.C.; MARTINS, D.S.R.; MELO, E.C. Umigrãos: Programa para o cálculo do teor de umidade de equilíbrio para os principais produtos agrícolas. Viçosa: Universidade Federal de Viçosa, Centreinar, 1995.

CORRÊA, P. C.; OLIVEIRA, G. H. H.; OLIVEIRA, A. P. L. R.; VARGAS-ELÍAS, G. A.; BAPTESTINI, F. M. Particlesizeandroastingonwatersorption in coniloncoffeeduringstorage. Coffee Science, v.11, p.221-233, 2016a.

CORRÊA, P. C.; OLIVEIRA, G. H. H.; OLIVEIRA, A. P. L. R.; VARGAS-ELÍAS, G. A.; SANTOS, F. L.; BAPTESTINI, F. M. Preservation of roasted and ground coffee during storage, part 1: Water content and repose angle. Revista Brasileira de Engenharia Agrícola e Ambiental, v.20, p.581-587, 2016b.

DRAPER, N.R.; SMITH, H. Applied regression analysis. New York:Wiley, 1998.

GONELI, A. L. D.; CORRÊA, P. C.; OLIVEIRA, G. H. H.; AFONSO JÚNIOR, P. C. Water sorption properties of coffee fruits, pulped and green coffee. LWT - Food Science and Technology, v.50, p.386-391, 2013.

HALSEY, G. Physical adsorption on non-uniform surfaces. Journal of Chemical Physics, v.16, p.931–937, 1948.

MOHSENIN, N. N. Physical properties of plant and animal materials.New York:Gordon and Breach Publishers, 1986.

OLIVEIRA, A. P. L. R.; CORRÊA, P. C.; REIS, E. L.; OLIVEIRA, G. H. H. Comparative Study of the Physical and Chemical Characteristics of Coffee and Sensorial Analysis by Principal Components. Food AnalyticalMethods, v.8, p.1303-1314, 2015.

OLIVEIRA, G. H. H.; CORRÊA, P. C.; SANTOS, F. L.; VASCONCELOS, W. L.; CALIL JÚNIOR, C.; BAPTESTINI, F. M.; VARGAS-ELÍAS, G. A. Caracterização física de café após torrefação e moagem. Semina. CiênciasAgrárias, v.35, p.1813-1828, 2014.

OLIVEIRA, G. H. H.; CORRÊA, P. C.; OLIVEIRA, A. P. L. R.; BAPTESTINI, F. M.; VARGAS-ELIAS, G. A. Roasting, grinding, and storage impact on thermodynamic properties and adsorption isotherms of arabica coffee. Journal of Food Processing and Preservation, v.41, p.1-12, 2017.

OSWIN, C. R. The kinetic of package life. III Isotherm. Journal of Chemical Industry, v.65, p.419–421, 1946.

SAMAPUNDO, S.; DEVLIEGHERE, F.; DE MEULENAER, B.; ATUKWASE, A.; LAMBONI, Y.; DEBEVERE, J.M. Sorption isotherms and isosteric heats of sorption of wholeyellow dent corn. Journal of Food Engineering, v.79, p.168–175, 2007.




DOI: https://doi.org/10.34117/bjdv6n4-319

Refbacks

  • There are currently no refbacks.