Thin-layer Drying Kinetics of Robusta Coffee

Title & Authors
Thin-layer Drying Kinetics of Robusta Coffee
Nilnont, Wanich; Phitakwinai, Sutida; Thawichsri, Kosart;

Abstract
This paper was aimed to study the drying kinetics of coffee and to investigate the thin-layer drying kinetics of coffee by using a convective air dryer. The coffee was dried for the temperatures of 40, 50 and $\small{60^{\circ}C}$ with relative humidity in the range of 14-25% the airflow rate fixed at 1 m/s. According to the experiment result, the drying rate curve showed that drying process took place only in the falling rate period. Seven thin layer drying models (Newton, Page, Henderson and Pabis, Logarithmic, Wang and Singh, Two terms, Modified Henderson and Pabis) were fitted to the experimental moisture content data. The Two-trem model was found to be a better model for describing the characteristics of coffee for the temperatures of 40, 50 and $\small{60^{\circ}C}$. The effective moisture diffusivity of coffee increased when the drying temperature increased. The value was in the range of $\small{4.5028{\times}10^{-11}}$ to $\small{6.4803{\times}10^{-11}m^2/s}$.
Keywords
Coffee;Diffusivity;Drying;Model;
Language
English
Cited by
References
1.
Hossain,M.A. and Bala,B.K. 2002. Thin-layer drying characteristics for green chilli.Drying Technology. Vol. 20 (2), pp. 489 - 505.

2.
Goyal,R.K., Kingsley,A.R.P.,Manikantan,M.R.,Ilyas,S.M.2006.Thin-layer drying of raw mango slices. Biosystems Engineering. Vol.95(1).pp.43-49.

3.
Kaya,A.,Aydin,O.,Demirtus,C.2007. Drying kinetic of red delicious apple. Biosystems Engineering. Vol.96(4).pp.517-524.

4.
Janjai,S.,Precoppe,M.,Lumlert,N.,Mahayothee,B.,Bala,B.K.,Nagle,M.,Muller.J.2011.Thin-layer drying of litchi. Food and Bioproducts Processing. Vol.(89).pp.194-201

5.
Janjai, S.Lamlert, N. Intawee, P. Mahayothee, B. Haewsungcharern, M. BalaB.K. and Muller, J.2007. Moisture Diffusivity Determination of Different Part of Longan Fruit. Journal of Food Propertie.Vol .10 .pp.471-478

6.
Bala,B.K. 1998.Drying and Storage of Cereal Grain, New Delhi, Oxford & IBH Publishing