DRYING CHARACTERISTICS OF OKRA BY DIFFERENT SOLAR DRYERS

Document Type : Original Article

Authors

1 Prof. and Head of Agric. Eng. Dept., Fac. of Agric., Minoufiya Univ.. Egypt.

2 Assoc. Prof., Agric. Eng. Dept., Fac. Of Agric., Minoufiya Univ.. Egypt.

3 Assistant Lecturer, Agric. Eng. Dept, Fac. Of Agric., Minoufiya Univ.., Shiben El Kom, Egypt.

Abstract

Drying of agricultural products is the great importance for preservation of food by human beings. Solar drying refers to a technique that utilizes incident solar radiation to convert it into thermal heat energy for drying purposes. The drying operation is mainly affected by variation of the air drying temperature, air flow rate and air relative humidity. The research was carried out to study the drying characteristics of okra to achieve highly drying rates and good quality. Three similar drying units were designed and manufactured in the Faculty of Agricultural., Menoufiya University and installed on the roof of Agricultural Engineering building. Each unit consists of solar collector, drying chamber, drying trays, chimney, and suction fan. Drying characteristics of okra treated by 1.0%sodium carbonates at boiling point for three minuets under different drying systems and flow rates of air 0.075 m3/sec, 0.149 m3/sec, and 0.249 m3/sec at the same time. Computer program used to define the fit mathematical model described the dying curves of okra in different conditions. The obtained results showed that, indirect dryer for drying okra at air flow rate of 0.075 m3/sec achieved the best quality. The drying efficiency was decreased as, the moisture content of okra crop reduced.

Main Subjects

References

Adom, K. K.; V. P. Dzogbefia; and W. O. Ellis (1997) "Combined effect of drying time and slice thickness on the solar drying of okra". J. Sci. Food Agric. (73), 315-320.
Awady, M.N.; A.M. Moustafa; and M.A. Genaidy (1988) "A trial on solar energy drying for agricultural products with simple setup". Misr, J. Ag. Eng., 5(3):377-392.
Ebru, K. A.; B. Yasar; and Y. Cengiz (2003) "Thin layer drying of red pepper". J. of  Food Eng., (59):99–104.
El-Shiatry, M.A.; J. Muller.; and W. Muhlbauer; (1992) "Drying of fruits and vegetables with solar energy in Egypt". Agricultural Mechanization in Asia, Africa and Latin America 22 (4): 61-64. Cited by El- Yateem, (1995).
El-Yateem, S. M. E. (1995) "Studies on the drying of some vegetables and fruits". M.Sc Thesis, Food Technology, Dep., Faculty of Agriculture, El-Minufiya University.
FAO, (2003) "Fao Stat Database". Available from: <http:// faostat.fao.org>.
Ghanem, T. H. (2003) "Improving Thermal Efficiency of A Flat Plate Solar Collector Using Nontraditional Coating Under Quasisteady conditions". Misr J. Ag. Eng., 20 (2):498-514.
Ibrahim, D. (2005)"Drying characteristics and kinetics of okra", Journal of FoodEngineering 69,(3) 275–279.
Lahsasni. S.; M. Kouhila; M. Mahrouz; A. Idlimam; and A. Jamali (2004) "Thin layer convective solar drying and mathematical modeling of prickly pear peel (Opuntia ficus indica)". Energy;29(2):211–24.
Midilli, A.; and H. Kucuk (2003) "Energy and exergy analyses of solar drying process of pistachio".  Energy 28,  539–556.
Mohamed, L. A.; M. Kouhila; A. Jamali; S. Lahsasni; N. Kechaou; and M. Mahrouz (2005) "Single layer solar drying behavior of Citrus aurantium leaves under forced convection". Energy Conversion and Management, 46:1473–1483.
Saad, M. M.; S. S. Rezk; and M. N. Metweally (1992) "Using the solar energy in drying the agricultural products". El-Dar El-Dawlia for Pub. And Delivering, Cairo, Egypt, (In Arabic)
Steinfield, A.; and I. Segal (1986) "A simulation model for solar thin layer drying process". Drying Technology, 4: 535–542.
Togrul, T. I.; and D. Pehlivan (2002) "Mathematical modelling of solar drying of apricot in thin layers". J. of Food Eng; 55 (3):209–16.
Yaldiz , O.; C. Ertekin;  and H. Ibrahim Uzun (2001) "Mathematical modeling of thin layer solar drying of sultana grapes". Energy 26: 457–465.
Yaldiz. O.; and C. Ertekin (2001) "Thin layer solar drying of some vegetables". Drying Technoly;(19) (3&4):583–97.
Misr Journal of Agricultural Engineering
Volume 27, Issue 1
January 2010
Pages 294-312

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