Thermodynamics of Moisture Sorption in Winged Bean Seed and Gari

Fasina, Oladiran; Ajibola, O.O.; Tyler, Robert T.

doi:10.1111/j.1745-4530.1999.tb00496.x

Cited by 91 publications

(89 citation statements)

References 18 publications

(7 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The results shown that the spreading pressure increased with increasing water activity and, at a given water activity, decreased with increasing temperature. The trends of spreading pressures with respect to temperature and water activity for adsorption and desorption were similar to those determined by Fasina et al (1999) for winged bean and gari, Aviara and Ajibola (2002) for melon seed and cassava, McMinn and Magee (2003) for potato.…”

Section: Spreading Pressuresupporting

confidence: 75%

Thermodynamic analysis of sorption isotherms of cassava (Manihot esculenta)

et al. 2012

View full text Add to dashboard Cite

Sorption isotherms of cassava were determined experimentally using a static gravimetric method at 30, 45 and 60°C and within the range of 0.10-0.90 water activity. At a constant water activity, equilibrium moisture content decreased with increasing temperature. The equilibrium moisture content increased with increasing water activity at a given temperature. The experimental results were modelled using seven sorption models using non-linear regression technique. Results demonstrated that the GAB model adequately predicted equilibrium moisture content of cassava for the range of temperatures and water activities studied. The thermodynamic functions such as net isosteric heat of sorption, differential entropy of sorption, net integral enthalpy and entropy were evaluated to provide an understanding of the properties of water and energy requirements associated with the sorption behaviour. Net isosteric heat and differential entropy decreased with increasing equilibrium moisture content. The net integral enthalpy decreased while net integral entropy increased with increasing equilibrium moisture content. Net integral entropy was negative in value. All thermodynamic functions were adequately characterised by a power law model. The point of maximum stability was found between 0.053 and 0.154 kg water/kg db for cassava.

show abstract

Section: Spreading Pressuresupporting

confidence: 75%

Thermodynamic analysis of sorption isotherms of cassava (Manihot esculenta)

et al. 2012

View full text Add to dashboard Cite

show abstract

“…The design of more efficient drying systems and storage systems for crops require knowledge of energy requirements, state and mode of moisture sorption within them [6]. This could be achieved by stating the correct mathematical models to estimate the heat and mass transfer mechanisms.…”

Section: Introductionmentioning

confidence: 99%

“…It is the total energy required to transfer water molecules from vapor state to a solid surface and vice-versa, as well as a measure of work done by a system to accomplish adsorption or desorption process. It is therefore used as an indicator of the state of adsorbed water by solid particles [6]. Isosteric heat is useful in predicting drying models, calculating energy consumption during the drying or wetting of agricultural materials, the design of drying equipment and describing any heat and mass transfer related processes [6,[9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Isosteric Heats of Water Vapor Sorption in Two Castor Varieties

Ojediran¹,

Raji²,

Owamah³

2013

J Chem Eng Process Technol

View full text Add to dashboard Cite

Equilibrium moisture content-water activity data for two varieties of castor (GSS and WBS) at temperatures 30, 40, 50, 60 and 70°C and water activity range of 0.07-0.98 were determined using the static gravimetric method. A nonlinear regression programme was used to fit four sorption isotherm models (modified Halsey, modified Henderson, modified Oswin and modified Guggenheim-Anderson-de Boer (GAB)) to the experimental data. These models were then compared using standard error of estimate and randomness of residuals. The sorption isosteric heats were determined by the application of Clausius-Clapeyron equation. The modified Oswin and modified Halsey proved the best for predicting equilibrium moisture content of castor with standard error of estimate of 0.238 and 0.242 for GSS and WBS respectively. The isosteric heats decreased exponentially with increase in moisture content and approached the latent heat of pure water at a free water point of between 13 and 16% moisture content (d.b). The difference in isosteric heats of both varieties was not significant.

show abstract

“…It represents the surface excess free energy [24]. It acts as a second pressure [12] and results in increase in surface tension on bare sorption sites due to the sorbed molecules on them [25]. It was calculated using an analytical procedure .…”

Section: Net Isosteric Heat Of Sorptionmentioning

confidence: 99%

Moisture Sorption Isotherm of Preconditioned Pressure Parboiled Brown Rice

M¹,

Sk²

2015

J Food Process Technol

View full text Add to dashboard Cite

The pressure parboiling of paddy was carried out at 294.204 kPa for 7 min and preconditioning of brown rice was carried out in fluidized bed dryer at 60-80°C. The moisture sorption isotherms of pressure parboiled preconditioned brown rice at different salt concentrations (0, 2, 3, 3.5 and 4%) were obtained at 20 ± 1°C, 25 ± 1°C, and 30 ± 1°C. The experimental data of sorption isotherm were fitted with some of sorption models (GAB, MGAB, MCPE, MOSE, MHEE, and MHAE models). According to the statistical results, the MGAB model gave the best fit to the experimental sorption data and MHAE model was the least adequate. Sorption isotherm data were used to determine the some thermodynamic functions. The net isosteric heat of sorption was determined from the best fitting equation using the Claussius-Calpeyron equation. The net isosteric heat of sorption decreased with increasing moisture content and increased with increasing salt concentration same trend was observed in entropy of sorption. The spreading pressure increased with increasing water activity and salt concentration and decreased with increasing temperature. The net integral enthalpy decreased with increasing moisture content and increased with increasing salt concentration and reverse trend was observed in integral entropy.

show abstract

Thermodynamics of Moisture Sorption in Winged Bean Seed and Gari

Cited by 91 publications

References 18 publications

Thermodynamic analysis of sorption isotherms of cassava (Manihot esculenta)

Thermodynamic analysis of sorption isotherms of cassava (Manihot esculenta)

Isosteric Heats of Water Vapor Sorption in Two Castor Varieties

Moisture Sorption Isotherm of Preconditioned Pressure Parboiled Brown Rice

Contact Info

Product

Resources

About