Water diffusion coefficients of selected cereals and legumes grown in Ghana as affected by temperature and variety
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Date
2011-06-19
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Abstract
The kinetics of water absorption by six newly released maize (Abrohemaa, Omankwa, Abotem,Abeleehi, Dorke SR and Akposoe), two cowpea (Tonaand Nhyira) and two soybeans (NagbaarandAnidaso) hybrids of cereals and legumes grown in Ghana were studied by a gravimetric method during soaking at four temperatures of 30, 40, 50 and 60ºC to determine their moisture diffusivity. The results showed that the absorption kinetics followed Fick's law of diffusion during the first hours of soaking and the water absorption patterns were dependent on temperature and variety. The estimated values for water diffusion coefficients varied from 2.54 x 10-10 to 4.89 x 10-10 m2/s, 4.36 x 10-10 to 6.28 x 10-10 m2/s and from 2.90 x 10-10 to 6.75 x 10-10m2/s for maize, cowpea and soybean varieties respectively. An Arrhenius-type equation described the strong temperature effect on the diffusion coefficient with activation energies ranging from 7.04 to 9.09 kJ/mol for maize 7.73 to 8.56 kJ/mol for cowpea and 5.51 to 8.14 kJ/mol for soybeans
Description
A thesis submitted to the Department of Agricultural Engineering, Kwame Nkrumah University of Science and Technology in partial fulfilment for the requirements for the degree of Master of Science in Food and Postharvest Engineering
Keywords
Maize, Soybean, Cowpea Arrhenius–type equation, Diffusion coefficient, Modelling, Water Absorption