In this study, water absorption characteristics of some rice varieties (Bisalayi, FARO 61, FARO 60, FARO 52 and FARO 44) from Nigeria were studied at 30°C, 45°C, 60°C and 75°C by determining the in...In this study, water absorption characteristics of some rice varieties (Bisalayi, FARO 61, FARO 60, FARO 52 and FARO 44) from Nigeria were studied at 30°C, 45°C, 60°C and 75°C by determining the increase in grain weight as a function of time during soaking. Differences in moisture content among the selected varieties of paddy during soaking were significant (P < 0.05) at all temperatures considered. Using the experimental moisture data, a non-linear regression procedure was applied to an analytical solution of the Fick’s second law of the diffusion for an infinite cylinder. The predicted values of instantaneous moisture contents were in good agreement with the experiential data with R2 of (0.834 - 0.997). Water absorption rate was found to increase with soaking temperature, while water saturation time decreased with temperature. Average values of diffusion coefficients of moisture during soaking of paddy rice at different temperatures (30°C, 45°C, 60°C and 75°C) were estimated as 6.25 × 10 -11, 6.28 × 10 -11, 7.02 × 10 -11, and 5.51 × 10 -11 and 5.52 × 10 -11 m2/s for Bisalayi, FARO 61, FARO 60, FARO 52 and FARO 44, respectively. The activation energies of the diffusivity through different varieties of rice grains werecalculated using Arrhenius-type equation for diffusion dependence on temperature and were determined as 41.96, 38.69, 40.16, 34.05 and 42.12 kJ/mole for Bisalayi, FARO 61, FARO 60, FARO 52 and FARO 44 for the respectively rice variety above.展开更多
Hydrodynamic characteristics and its associated thermodynamic and textural variation of three common Malawian beans varieties (Boma, Sugar and Mandondo) during soaking were evaluated at four temperature regimes (25...Hydrodynamic characteristics and its associated thermodynamic and textural variation of three common Malawian beans varieties (Boma, Sugar and Mandondo) during soaking were evaluated at four temperature regimes (25°C, 35°C, 45°C and 55°C). The equilibrium water uptake of 127% ± 5% was reached in 10, 6, and 4 hours respectively, for 25°C, 35°C and 45°C. Not much variation was observed between 45°C and 55°C except for sugar beans where equilibrium water uptake was reached within two hours of soaking at 55°C. Three models namely Peleg, two-parameter Mitscherlich model and viscoelastic model were used to evaluate the comparative predicting capabilities of the bean hydrodynamic characteristics. All models predicted the water absorption accurately (R2 > 0.903, RMSE activation kinetic parameters to be between 25 - 65 kJ/mol. Sugar beans were found to be the least hard. At room temperature, its hardness reduced by 58% within 2 hours of soaking. At higher temperature (55°C) hardness values were reduced to 12.5%, 11.1% and 15.0% within the first hour for Boma, Sugar and Mandondo beans, respectively.展开更多
文摘In this study, water absorption characteristics of some rice varieties (Bisalayi, FARO 61, FARO 60, FARO 52 and FARO 44) from Nigeria were studied at 30°C, 45°C, 60°C and 75°C by determining the increase in grain weight as a function of time during soaking. Differences in moisture content among the selected varieties of paddy during soaking were significant (P < 0.05) at all temperatures considered. Using the experimental moisture data, a non-linear regression procedure was applied to an analytical solution of the Fick’s second law of the diffusion for an infinite cylinder. The predicted values of instantaneous moisture contents were in good agreement with the experiential data with R2 of (0.834 - 0.997). Water absorption rate was found to increase with soaking temperature, while water saturation time decreased with temperature. Average values of diffusion coefficients of moisture during soaking of paddy rice at different temperatures (30°C, 45°C, 60°C and 75°C) were estimated as 6.25 × 10 -11, 6.28 × 10 -11, 7.02 × 10 -11, and 5.51 × 10 -11 and 5.52 × 10 -11 m2/s for Bisalayi, FARO 61, FARO 60, FARO 52 and FARO 44, respectively. The activation energies of the diffusivity through different varieties of rice grains werecalculated using Arrhenius-type equation for diffusion dependence on temperature and were determined as 41.96, 38.69, 40.16, 34.05 and 42.12 kJ/mole for Bisalayi, FARO 61, FARO 60, FARO 52 and FARO 44 for the respectively rice variety above.
文摘Hydrodynamic characteristics and its associated thermodynamic and textural variation of three common Malawian beans varieties (Boma, Sugar and Mandondo) during soaking were evaluated at four temperature regimes (25°C, 35°C, 45°C and 55°C). The equilibrium water uptake of 127% ± 5% was reached in 10, 6, and 4 hours respectively, for 25°C, 35°C and 45°C. Not much variation was observed between 45°C and 55°C except for sugar beans where equilibrium water uptake was reached within two hours of soaking at 55°C. Three models namely Peleg, two-parameter Mitscherlich model and viscoelastic model were used to evaluate the comparative predicting capabilities of the bean hydrodynamic characteristics. All models predicted the water absorption accurately (R2 > 0.903, RMSE activation kinetic parameters to be between 25 - 65 kJ/mol. Sugar beans were found to be the least hard. At room temperature, its hardness reduced by 58% within 2 hours of soaking. At higher temperature (55°C) hardness values were reduced to 12.5%, 11.1% and 15.0% within the first hour for Boma, Sugar and Mandondo beans, respectively.
