Abstract
The curves of dehydration by osmosis of 1 cm3 apple cubes have been simulated assuming the existence of two diffusional species. The diffusivity value of the two species, water and sucrose, was obtained by using a numerical method of non-linear regression analysis. The influence of the solution conditions (temperature and sucrose concentration) on the absorption rate was evaluated. Two sets of experiments were carried out: experiments at 70°Brix and different solution temperatures (30, 40, 50, 60 and 70 °C) on the one hand, and experiments at 50 °C and different solution concentrations (30, 50 and 70°Brix) on the other. The proposed diffusive model is able to explain 98% of the total variance. This model is also applicable to the simulation of dehydration by osmosis for other food products.
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Received: 13 May 1996
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Simal, S., de Mirabó, F., Deyá, E. et al. A simple model to predict mass transfers in dehydration by osmosis. Z Lebensm Unters Forsch 204, 210–214 (1997). https://doi.org/10.1007/s002170050065
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DOI: https://doi.org/10.1007/s002170050065
- Key words Dehydration
- Osmosis
- Mathematical model
- Mass transfer
- [C Average sucrose concentration (g sucrose/g d.m.)
- C* average dimensionless sucrose concentration
- Cdis osmotic solution concentration (g sucrose/g d.m.)
- Ce equilibrium sucrose concentration (g sucrose/g d.m.)
- Co initial sucrose concentration (g sucrose/g d.m.)
- Cl local sucrose concentration (g sucrose/g d.m.)
- DSeff diffusivity coefficient of sucrose (m2/h)
- DSo preexponential factor in Eq. 9
- DWeff diffusivity coefficient of water (m2/h)
- DWo preexponential factor in Eq. 8
- ESa energy of activation in Eq. 9 (J/mol)
- EWa energy of activation in Eq. 8 (J/mol)
- L half-thickness of the solid (m)
- Po initial sample weight (g)
- Psso initial dry matter (g)
- Pssf final dry matter (g)
- Sy standard deviation (sample) (g water/g d.m.)2
- Syx standard deviation (estimation) (g water/ g d.m.)2
- %var percentage of explained variance
- W average moisture content (g water/g d.m.)
- We equilibrium moisture content (g water/g d.m.)
- W1 local moisture content (g water/g d.m.)
- Wo initial moisture content (g water/g d.m.)
- WPsso moisture content referred to the initial dry matter (g water/ g d.m.)
- x x-axis distance (m)
- y y-axis distance (m)
- z z-axis distance (m)
- ΔW water losses (g)
- ΔP mass losses (g)
- ΔPss mass gain (g)
- ΔPss/Psso solute gain referred to the initial dry matter (g solute/g d.m.)
- Ψ dimensionless moisture content]