Vacuum Drying Characteristics of Some Vegetables

Document Type : Research Note


1 Zakipour, Esmaeil; Hamidi, Zohreh*+ Department of Food Science and Technology, Faculty of Agriculture, Tarbiat Modares University, P.O. Box 14115-336 Tehran, I.R. IRAN

2 Department of Food Science and Technology, Faculty of Agriculture, Tarbiat Modares University, P.O. Box 14115-336 Tehran, I.R. IRAN


In this research the drying of four kinds of vegetables was investigated in a vacuum dryer. The effect of temperature on drying rate of samples at various temperatures (30, 35 and 45 °C) was studied. Six thin-layer drying models were fitted to drying data and suitable model was selected from them. Then effective moisture diffusivity and activation energy of samples were calculated. The Diffusion approximation model gave excellent fit forfenugreek and mint leaves and vegetative parts of leek and the page model was considered adequateto describe the thin-layer drying behavior of parsley leaves. The effective diffusivity values changed from 2.92×10-10 to 9.81×10-10, 1.77×10-10 to 5.99×10-10, 9.3×10-11 to 1.7×10-10 and 1.27×10-9 to 3.4×10-9 for fenugreek, mint and parsley leaves and vegetative parts of leek, respectively. An Arrhenius type of equation was used to evaluate the effect of temperature on the effective diffusivity and the activation energy values was found 66.36, 66.34, 32.27 and 51.16 kJ/ mol for fenugreek, mint and parsley leaves and vegetative parts of leek, respectively.


[1] Makai P.S., Makai S., Kismanyoky A.,Comparative Test of Fenugreek (Trigonella foenum-graecum L.), Journal of Central European Agriculture, 5, p. 259 (2004).
[2] Rose P.,Whiteman M., Moore P.K., Zhu Y.Z., Bioactive S-alk(en)yl Cysteine Sulfoxide Metabolites in the Genus Allium: the Chemistry of Potential Therapeutic Agents, Published as an Advance Article on the Web (,Cambridge,UK (2005)
[3] Albaugh A., Eggers D., Crowe F., Morris M., Reerslev J., Passmore K., Pest Management Strategic Plan for Pacific Northwest Mint Production, Summary of a Workshop, Portland, Oregon (2002).
[4] Akpinar E.K., Bicer Y., Cetinkaya F., Modeling of Thin Layer Drying of Parsley Leaves in a Convective Dryer and under Open Sun, Journal of Food Engineering, 75, p. 308 (2006).
[5] Krokida M.K., Marinos-Kouris D., Rehydration Kinetics of Dehydrated Products, Journal of Food Engineering, 57(1), p. 1 (2003).
[6] Okos M.R., Narsimhan G., Singh R.K., Witnauer A.C., Food dehydration. In: D.R. Heldman & D.B. Lund (Eds.), "Handbook of Food Engineering", Marcel ekker,New York(1992).
[7] Jaya S., Das H., A Vacuum Drying Model for Mango Pulp, Drying technology, 21(7), p. 1215 (2003).
[8] Sablani S.S., Datta A.K., Rahman M.S., Mujumdar, A.S., Mathematical Modeling Techniques in Food and Bioprocesses. In: Taylor & Francis (Eds.), "Handbook of Food and Bioprocess Modeling Techniques", Boca raton,London,New York(2006).
[9] Akpinar E.K., Mathematical Modeling of Thin Layer Drying Process under Open Sun of Some Aromatic Plants, Journal of Food Engineering, 77, p. 864 (2006).
[10] Doymaz I., Tugrul N., Pala M., Drying Characteristics of Dill and Parsley Leaves, Journal of Food Engineering, 77, p. 559 (2006).
[11] Kaya A., Aydın O., An experimental Study on Drying Kinetics of Some Herbal Leaves, Energy Conversion and Management, 50, p. 118–124 (2009).
[12] Ozbek B., Dadali G., Thin-Layer Drying Characteristics and Modeling of Mint Leaves Undergoing Microwave Treatment, Journal of Food Engineering, 83, p. 541 (2007).
[13] Akpinar E.K., Bicer Y., Midilli A., Modeling and Experimental Study on Drying of Apple Slices in a Convective Cyclone Dryer, Journal of Food Process Engineering, 26(6), p. 515 (2003).
[14] Gunhan T., Demir V., Hancioglu E., Hepbasli A., Mathematical Modeling of Drying of Bay Leaves, Energy Conversion and Management, 46(11–12), p. 1667  (2005).
[15] Yaldiz O., Ertekin C., Thin Layer Solar Drying of Some Vegetables, Drying Technology,19, p. 583 (2001).
[16] O’Callaghan J.R., Menzies D.J., Bailey P.H., Digital Simulation of Agricultural Dryer Performance, Journal of Agricultural Engineering Research, 16, p. 223 (1971).
[17] Yagcioglu A., Degirmencioglu A., Cagatay F., Drying Characteristics of Laurel Leaves Under Different Drying Conditions, In: "Proceedings of the 7th International Congress on Agricultural Mechanization and Energy in Agriculture", pp 565-569.Adana,Turkey, 26–27 May (1999).
[18] Page G.E., Factors Influencing the Maximum Rates of Air Drying Shelled Corn in Thin Layers. M.S. thesis. Department of Mechanical Engineering,PurdueUniversity,Purdue,USA(1949).
[19] HendersonS.M., Progress in Developing the Thin-Layer Drying Equation, Transactions of the ASAE, 17, 1167–1168,1172 (1974).
[20] Sharaf-Elden, Y I., Blaisdell, J.L., Hamdy, M.Y., A Model for Ear Corn Drying, Transactions of the ASAE, 5,1261-1265 (1980).
[21] Kassem A.S., Comparative Studies on Thin Layer Drying Models for Wheat, In: "Proceedings of the 13th International Congress on Agricultural Engineering", 6, pp. 2–6 (1998).
[22] Ertekin Y., Yaldiz O., Drying of Eggplant and Selection of a Suitable Thin Layer Drying Model, Journal of Food Engineering, 63, p. 349 (2004).
[23] Crank J., "The mathematics of Diffusion", (2nd ed.).Oxford,UK: Clarendon Press (1975).
[24] Sacilik K., Effect of Drying Methods on Thin-layer Drying Characteristics of Hull-Less Seed Pumpkin (Cucurbita pepo L.). Journal of Food Engineering, 79(1), p. 23 (2007)..
[25] Sobukola O.P., Dairo O.U., Sanni L.O., Odunewu A.V., Fafiolu B.O., Thin Layer Drying Process of
Some Leafy Vegetables under Open Sun, Food Science and Technology International, 13(1), p. 35 (2007).
[26] Wang Z., Sun J., Chen F., Liao X., Hu X., Mathematical Modeling on Thin Layer Microwave Drying of Apple Pomace with and Without Hot-Air Pre Drying, Journal of Food Engineering, 80(2), p. 536 (2007)
[27] Brennan J.G., Dehydration (Drying). In: WILEY-VCH Verlag GmbH & Co. KGaA (Eds.), Food Processing Handbook", (pp. 85–88),Weinheim ,Germany (2006).
[28] Belghit A., Kouhila M., Boutaleb B.C., Experimental Study of Drying Kinetics of Forced Convection of Aromatic Plants, Energy Conversion and Management, 41, p. 1303 (2000).
[29] Akpinar E.K., Bicer Y., Modeling of the Drying of Eggplants in Thin-Layer, International of Journal of Food Science and Technology, 39, p. 1 (2004).
[30] DoymazI., Thin-layer Drying Behavior of Mint Leaves, Journal of Food Engineering, 74, p. 370 (2006).
[31] Lee J.H., Kim H.J., Vacuum Drying Kinetics of Asian White Radish (Raphanus sativus L.) Slices, LWT - Food Science and Technology, 42, p. 180 (2009).
[32] JenaS., Das H., Modeling for Vacuum Drying Characteristics of Coconut Press Cake, Journal of Food Engineering, 79, p. 92 (2007).
[33] Panchariya P.C., Popovic D., Sharma A.L., Thin-Layer Modeling of Black Tea Drying Process, Journal of Food Engineering, 52, p. 349 (2002).
[34] Kaymak-Ertekin F., Drying and Rehydrating Kinetics of Green and Red Peppers, Journal of Food Science, 67, p. 168 (2002).
[35] Simal S., Rossello C., Berna A., Mulet A., Drying of Shrinking Cylinder-Shaped Bodies, Journal of Food Engineering, 37, p. 423 (1998).