Advertisement

Heat and Mass Transfer

, Volume 52, Issue 12, pp 2649–2659 | Cite as

Experimental study of water desorption isotherms and thin-layer convective drying kinetics of bay laurel leaves

  • Thouraya GhnimiEmail author
  • Lamine Hassini
  • Mohamed Bagane
Original

Abstract

The aim of this work is to determine the desorption isotherms and the drying kinetics of bay laurel leaves (Laurus Nobilis L.). The desorption isotherms were performed at three temperature levels: 50, 60 and 70 °C and at water activity ranging from 0.057 to 0.88 using the statistic gravimetric method. Five sorption models were used to fit desorption experimental isotherm data. It was found that Kuhn model offers the best fitting of experimental moisture isotherms in the mentioned investigated ranges of temperature and water activity. The Net isosteric heat of water desorption was evaluated using The Clausius–Clapeyron equation and was then best correlated to equilibrium moisture content by the empirical Tsami’s equation. Thin layer convective drying curves of bay laurel leaves were obtained for temperatures of 45, 50, 60 and 70 °C, relative humidity of 5, 15, 30 and 45 % and air velocities of 1, 1.5 and 2 m/s. A non linear regression procedure of Levenberg–Marquardt was used to fit drying curves with five semi empirical mathematical models available in the literature, The R2 and χ2 were used to evaluate the goodness of fit of models to data. Based on the experimental drying curves the drying characteristic curve (DCC) has been established and fitted with a third degree polynomial function. It was found that the Midilli Kucuk model was the best semi-empirical model describing thin layer drying kinetics of bay laurel leaves. The bay laurel leaves effective moisture diffusivity and activation energy were also identified.

Keywords

Desorption Isotherm Equilibrium Moisture Content Isosteric Heat Moisture Ratio Effective Moisture Diffusivity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of symbols

aw

Water activity

Va

Air velocity (m/s)

T

Temperature (°K)

HR

Air relative humidity (%)

me

Water mass in the product (Kg)

ms

Dry matter mass (Kg)

X

Product moisture content at dry basis (Kg water/Kg dry matter)

X0

Initial moisture content (Kg water/Kg dry matter)

Xt

Average moisture content at time t (Kg water/Kg dry matter)

Xe

Equilibrium moisture content (Kg water/Kg dry matter)

XR

Moisture ratio

XRi,exp

ith experimental moisture ratio

XRi,pre

ith predicted moisture ratio

\(\overline{\text{XR}}\)

Average value of experimental moisture ratio

N

Number of observations

Z

Number of constants in the drying model

Qst,n

Net isosteric heat of desorption (kJ/mol)

R

Ideal gaz constant (J/mol/K)

P

Slope of the desorption isosters

F (φ)

Dimensionless draying rate

t

Time (s)

r

Space coordinate (m)

Deff

Effective moisture diffusivity (m2/s)

D0

Pre-exponential factor of Arrhenius equation (m2/s)

L

Thickness of sample (m)

Ea

Activation energy (kJ/mol)

a, b, c, k, k0, k1

Models constants

References

  1. 1.
    Skrubis BG (1982) The drying of bay leaves. Perfum Flavor 7(5):37–40Google Scholar
  2. 2.
    Ceylan A, Ozay N (1990) A study on the ontogenetical quality of bay leaves. J Fac Ege Univ 27(3):71–77Google Scholar
  3. 3.
    Yagcioglu A, Degirmencioglu A, Cagatay F (1999) Drying characteristic of bay leaves under different drying conditions. In: Proceeding of the 7th international congress on agricultural mechanization and energy, pp 26–27Google Scholar
  4. 4.
    Demir V (2004) Mathematical modeling and the determination of some quality paramaters of air-dried bay leaves. Biosyst Eng 88(3):325–335MathSciNetCrossRefGoogle Scholar
  5. 5.
    Sellami IH, Wannes WA, Bettaieb I, Berrima S, Chahed T, Marzouk B, Limam F (2011) Qualitative and quantitative changes in the essential oil of laurus nobilis as affected by different drying methods. Food Chem 126:691–697CrossRefGoogle Scholar
  6. 6.
    Doymaz I (2012) Thin layer drying of bay laurel leaves (Laurus Nobilis, L.). J Food Process Preserv 38(1):449–456CrossRefGoogle Scholar
  7. 7.
    Kenneth H (1990) Official methods of analysis. Association of Official Analytical Chemists, ArlingtonGoogle Scholar
  8. 8.
    Hassini L, Azzouz S, Peczalski R, Belghith A (2007) Estimate off potato convective moisture diffusivity from drying kinetics with correction for shrinkage. Newsp Food Eng 39:47–56CrossRefGoogle Scholar
  9. 9.
    Togrul IT, Pehlivan D (2004) Modelling of thin layer drying kinetics of some fruits under open-air sun drying process. J Food Eng 65:413–425CrossRefGoogle Scholar
  10. 10.
    Kuhn I (1964) A new theoretical analysis of adsorption phenomena, expression of the main regular types of adsorption isotherms by a single simple equation. J Colloid Sci 19:685–698CrossRefGoogle Scholar
  11. 11.
    Halsey G (1948) Physical adsorption on non-uniform surfaces. J Chem Phys 16:931–937CrossRefGoogle Scholar
  12. 12.
    Henderson SM (1952) A basic concept of equilibrium moisture. Trans Am Soc Agric Eng 33:29Google Scholar
  13. 13.
    Oswin CR (1946) The kinetics of package life III. Isotherm J Chem Ind 65:419–421CrossRefGoogle Scholar
  14. 14.
    Smith SE (1947) The sorption of water vapor by high polymers. J Am Chem Soc 69:646CrossRefGoogle Scholar
  15. 15.
    Rizvi SSH (1986) Thermodynamic properties of foods in dehydration. In: Rao MA, Rizvi SSH (eds) Engineering properties of foods. Marcel Dekker Inc, New York, p 223Google Scholar
  16. 16.
    Tsami E (1991) Net isosteric heat of sorption in dried fruits. J Food Eng 14:327–335CrossRefGoogle Scholar
  17. 17.
    Van Meel DA (1958) Adiabatic convection batch drying with recirculation of air. Chem Eng Sci 9:36–44CrossRefGoogle Scholar
  18. 18.
    Bruce DM (1985) Exposed-layer barley drying, three models fitted to new data up to 150C. J Agric Eng Res 32:337–347CrossRefGoogle Scholar
  19. 19.
    Wang CY, Singh RP (1978) Use of variable equilibrium moisture content in modeling rice drying. Trans Am Soc Agric Eng 11:668–672Google Scholar
  20. 20.
    Midilli A, Kucuk H, Yapar ZA (2002) New model for single-layer drying. Dry Technol 20(7):1503–1513CrossRefGoogle Scholar
  21. 21.
    Crank J (1975) The mathematics of diffusion. Clarendon Press, OxfordzbMATHGoogle Scholar
  22. 22.
    Simal S, Femenia A, Llull P, Rosello C (2000) Dehydration of aloe vera: simulation of drying curves and evaluation of functional properties. J Food Eng 43:109–114CrossRefGoogle Scholar
  23. 23.
    Ait Mohamed L, Kouhila M, Lahsasnia S, Jamalia A, Idlimama A, Rhazia M, Aghfira M, Mahrouzb M (2005) Equilibrium moisture content and heat of sorption of Gelidium sesquipedale. J Stored Prod Res 41:199–209CrossRefGoogle Scholar
  24. 24.
    Chenarbon HA, Movahed Hasheminia SH (2012) Moisture sorption isotherms of Rosemary (Rosmarinus officinalis L.) flowers at three temperatures. Am Eurasian J Agric Environ Sci 12(9):1209–1214Google Scholar
  25. 25.
    Nourhène B, Mohammed K, Nabil K (2008) Experimental and mathematical investigations of convective solar drying of four varieties of olive leaves. Food Bioprod Process 86:176–184CrossRefGoogle Scholar
  26. 26.
    Medeni M, Fahrettin G (1997) The fitting of various models to water sorption isotherms of pistachio nut paste. J Food Eng 33:227–237CrossRefGoogle Scholar
  27. 27.
    Marcel E, Alexis K, Kapseu C (2010) Determination of the Gnetum africanum water sorption isotherms for use in the design of an adapted dryer. Int J Food Sci Technol 45:105–112Google Scholar
  28. 28.
    Kiranoudis CT, Maroulis ZB, Tsami E, Marinos-Kouris D (1993) Equilibrium moisture content and heat of desorption of some vegetables. J Food Eng 20:55–74CrossRefGoogle Scholar
  29. 29.
    Bories S, Prat M, (1996) Transferts de chaleur dans les milieux poreux, Technique de l’ingénieur, traité génie énergétique, N 600682, ISTRA B1, FranceGoogle Scholar
  30. 30.
    Jannot Y (2008) Isothermes de sorption: modèles et détermination, cours. http://www.thermique55.com/principal/thermiquesolaire.pdf
  31. 31.
    Brunauer S (1938) Adsorption of gases in multimolecular layers. J Am Chem Soc 60:309–319CrossRefGoogle Scholar
  32. 32.
    Langmuir I (1918) The adsorption of gases on plane surfaces of glass, mica and platinum. J Am Chem Soc 40:1361–1403CrossRefGoogle Scholar
  33. 33.
    Iglesias HA (1978) Equations for fitting water sorption isotherms of foods. J Food Technol 13:159–174Google Scholar
  34. 34.
    Lopez A, Iguaz A, Esnoz A, Virseda P (2000) Thin-layer drying behaviour of vegetable waste from wholesale market. Dry Technol 18:995–1006CrossRefGoogle Scholar
  35. 35.
    Benhamou A (2008) Diffusivité hydrique et cinétique de séchage solaire en convection forcée des feuilles de marjolaine. Revue des Energies Renouvelables 11(1):75–85Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Thouraya Ghnimi
    • 1
    Email author
  • Lamine Hassini
    • 2
  • Mohamed Bagane
    • 1
  1. 1.Applied Thermodynamics Unit Research, National Engineering School of Gabès, ENIGUniversity of GabèsGabèsTunisia
  2. 2.LETTM Laboratory, Sciences Faculty of TunisUniversity Tunis El ManarTunisTunisia

Personalised recommendations