An experimental study for the drying kinetics
of whole okra was carried out. In the study, different ages were considered by
taking into account influence of okra maturity on its convective drying. The 2D moisture evolution inside the product and
its maturity were evaluated by fitting experimental data
versus drying time. The water effective diffusion coefficient of okra at
different maturity
states was gotten by the experimental model using Fick’s second law. A
parametric study was carried out in the ranging of okra age from 2 to 7 days at
60℃, both fruits gathered on the same plant to avoid divergences due to okra
varieties that can induce difference on physical structure and the chemical
composition. It was found from the experimental results that okra maturity has
important influence on its behaviour during convective drying. At 2, 3, 4, 5
and 7 days old, the drying effective time was respectively 780, 1000, 1155, 850
and 750 min. Effective diffusivity of the okra in this
order of age was 1.38 × 10-10, 6.09 × 10-11, 1.23 × 10-11, 8.98 × 10-11, and 1.05 × 10-10 m2/s in the present study,
while the average initial moisture content was respectively 12.27, 9.00, 7.53, 5.97 and 4.92 Kgw/Kgdm.
References
[1]
Sankar, B., Abdul, J.C., Manivannan, P., Kishorekumar, A., Somasundaram, R. and Panneerselvam, R. (2008) Relative Efficacy of Water Use in Five Varieties of Abelmoschus esculentus (L.) Moench. under Water-Limited Conditions Colloids and Surfaces. Biointerfaces, 62, 125-129. http://dx.doi.org/10.1016/j.colsurfb.2007.09.025
[2]
Avallonea, S., Tiemtorea, T.W.E., Rivierb, C. and Trècheb, S. (2008) Nutritional Value of Six Multi-Ingredient Sauces from Burkina Faso. Journal of Food Composition and Analysis, 21, 553-558. http://dx.doi.org/10.1016/j.jfca.2008.04.012
[3]
Camciuc, M., Deplagne, M., Vilarem, G. and Gaset, A. (1998) Ocra (Abelmoschus esculentus L. Moench.) a Crop with Economic Potential for Set Aside Acreage in Frances Industrial. Crops and Products, 7, 257-264. http://dx.doi.org/10.1016/S0926-6690(97)00056-3
[4]
Sengkhamparn, N., Sagis, L.M.C., Renko de Vries, A., Henk Schols, H.A., Sajjaanantakul, T., Alphons, G.J. and Voragen, A.G.J. (2008) Physicochemical Properties of Pectins from Ocra Abelmoschus esculentus L. Moench. Food Hydrocolloids, 24, 35-41. http://dx.doi.org/10.1016/j.foodhyd.2009.07.007
[5]
Adelakun, O.E., Oyelade, O.J., Ade-Omowaye, B.I.O., Adeyemi, I.A. and Van de Venter, M. (2009) Chemical Composition and the Antioxidative Properties of Nigerian Ocra Seed (Abelmoschus esculentus Moench) Flour. Food and Chemical Toxicology, 47, 1123-1126. http://dx.doi.org/10.1016/j.fct.2009.01.036
[6]
Ouoba, K.H., Desmorieux, H., Zougmoré, F. and Naon, B. (2010) Caractérisation du Séchage Convectif du Gombo, Influence de la Découpe et de ses Constituants. Afrique SCIENCE, 10, 37-48. http://www.afriquescience.info
[7]
FAOSTAT (Food and Agricultural Organization of the United Nations) (2008) On-Line and Multilingual Database Currently Covering International Statistics. http://faostat.fao.org/site/339/default.aspx
[8]
Kordylas, J.M. (1991) Processing and Preservation of Tropical and Subtropical Foods. Macmillan Education Ltd.
[9]
Corzo, O., Bracho, N. and Alvarez, C. (2008) Water Effective Diffusion Coeffcient of Mango Slices at Different Maturity Stages during Air Drying. Journal of Food Engineering, 87, 479-484. http://dx.doi.org/10.1016/j.jfoodeng.2007.12.025
[10]
AOAC (Association of official Chemists) (1990) Official Methods of Analysis. Washington AC, 934-06.
[11]
Crank, J. (1975) The Mathematics of Diffusion. 2nd Edition, Oxford University Press, London, 69-88.
[12]
Nuh, D.N. and Brinkworth, B.J. (1997) A Novel Thin-Layer Model for Crop Drying. Transactions of the American Society of Agricultural Engineers, 40, 659-669.
[13]
Pala, M., Mahmutoglu, T. and Saygi, B. (1996) Effects of Pretreatments on Quality of Open-Air and Solar Dried Apricots. Nahrung/Food, 40, 137-141.
[14]
Riva, M. and Peri, C. (1986) Kinetics of Sun and Air Drying of Different Varieties of Seedless Grapes. Journal of Food Technology, 21, 199-208. http://dx.doi.org/10.1111/j.1365-2621.1986.tb00441.x
[15]
Rosello, C., Simal, S., SanJuan, N. and Mulet, A. (1997) Nonisotropic Mass Transfer Model for Green Bean Drying. Journal of Agriculture and Food Chemistry, 45, 337-342
[16]
Gogus, F. and Maskan, M. (1999) Water Adsorption and Drying Characteristics of Okra (Hibiscus Esculentus L.). Drying Technology, 17, 883-894. http://dx.doi.org/10.1080/07373939908917576
[17]
Gupta, P., Ahmed, J., Shivhare, U.S. and Raghavan, G.S.V. (2002) Drying Characteristics of Red Chilli. Drying Technology, 20, 1975-1987. http://dx.doi.org/10.1081/DRT-120015579
[18]
Madamba, P.S., Driscoll, R.H. and Buckle, K.A. (1996) The Thin-Layer Drying Characteristic of Garlic Slices. Journal of Food Engineering, 29, 75-97. http://dx.doi.org/10.1016/0260-8774(95)00062-3
