EFFECT OF DRYING CONDITIONS ON DRYING BEHAVIOR AND QUALITY OF ONION SLICES | ||||
| Misr Journal of Agricultural Engineering | ||||
| Article 14, Volume 31, Issue 2, April 2014, Page 575-598 PDF (1.13 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/mjae.2014.99624 | ||||
 View on SCiNiTO | ||||
| Author | ||||
| G.R. Gamea | ||||
| Assoc. Prof. of Agric. Eng.Dept. Fac. Of Agriculture, Minoufiya Un., Egypt | ||||
| Abstract | ||||
| Drying of agricultural products is the great importance for preservation of food human beings. The drying operation is mainly affected by variation of the air temperature, air velocity,, air relative humidity and other factors. The aim of this research was to investigate influence of some factors such as drying air temperature (40, 50, 60, 70, and 80 °C) and onion slices thickness (4, 6, and 8 mm) on the thin layer convection drying behavior of white onions slices at 1.5 m/s air velocity. Drying experiments were conducted using a convection tray dryer(UOP 8 Tray Dryer, Armfield, UK, S.N : 016679-001). The dryer is equipped with controllers for controlling the temperature and airflow velocity. Temperature changes of dried samples, as well as relative humidity and temperature of drying air were measured during the drying process. Rehydratation ratio, color, texture and sensory properties were used as a parameter for the dried sample quality. The drying curves were fitted with different moisture ratio equations given by several researchers. Pag's equation (exponential model) fitted very well the experimental data and it is possible to accurately simulate the thin layer drying behavior of onion slices at different air temperature. Two well-defined falling rate periods and a very short constant rate period at lower air temperature were observed. Drying constants ( k and n) were greatly affected by drying air temperature and slice thickness. Drying time decreases considerably with increase in hot air temperature. During rehydration of dried onions,3.08 to 3.71 of rehydration ratio by the drying process was obtained. Slice thickness had a significant effect on the rehydration ratio. Drying of onion slices at range of (40 – 60°C) revealed optimum color values, meanwhile drying at 70- 80 °C gave least acceptable color values. So if the economics of the process is considered, drying at 50 to 60 °C is generally recommended | ||||
| References | ||||
|
AmerEssa, A. H. (1998). The engineering factors affecting handling and loss reduction of egg production. Ph.D. thesis, University of Minoufiya, Egypt.
AOAC (1990). Official methods of analysis (13th ed.) Washington, DC, USA, Association of official analytical chemists.
Arslan, D. and Ozcan, M. M. (2010). Study the effect of sun, oven and microwave drying on quality of onion slices. LWT – Food science and Technology, 43, 1121 – 1127
Berinyuy, J. E., Tangka, J. K. and Weka, Fotso, G. M. (2012). Enhancing natural convection solar drying of high moisture vegetables with heat storage
Bruce, M.(1985). Exposed layer barley drying: three models fitted to new data up to150°C. J. Agric. Eng. Resear., 32: 337-347.
Diamante, L. M. (1994). Drying characteristics of sweet potato slices. In Proceedings of the international conference of preservation and security (pp. 187–199).
CAPMS. (2011). Annual year book for general statistics. Central Agency for public Mobilization and Statistics of A.R.E., Egypt.
Doymaz, I., and Pala, M. (2002). The effects of dipping pretreatments on air-drying rates of the seedless grapes. Journal of Food Engineering, 52(4), 413–417
Doymaz, I. (2004).Convective air drying characteristics of thin layer carrots. J. Food Eng., 61: 359–364.
Gustavssion, J., Cederberg, C. and Sonesson, U. (2011).Global food losses and food waste.
Hathan, B. S. and Malhotra, T. (2012) Drying kinetics of osmotically pretreated carrot sheared to be used for preparation of sweet meat.Agric. Eng. Int. :CIGR Journal, 14 (1) 125-135
Kalse, S. B., Patil, M. M., and Jain, S. K. (2012) Microwave Drying of onion slices. Research Journal of Chemical Sciences, 2(4), 57-60
Koyuncu, T, Tosun, I.andpinar, Y. (2007). Drying charateristics and heat energy requirement of cornelian cherry fruits (cornus mas L). journal of Food Engineering. 78 (2), 737 – 739
Kummar, D. G. P., Hebbar, H. U., and Ramesh, M. N. (2006). Suitability of thin layer models for infrared-hot air-drying of onion slices. LebensmittelWissenschaft Und Technologie, 39, 700- 705
Lin, T. M., Durance, T. D. and Scaman, C. H. (1998). Characterization of vacuum microwave air and freeze dried carrot slices. Food Research International, 4, 111-117
Mohamed, M. A., Gamea, G.R. and Keshek, M. H. (2005). Drying characteristics of okra by different solar dryers.Misr j. Agr. Eng., 27 (1) 294-312.
Midilli, A., Kucuk, H. and Yapar, Z. (2002). A new model for single layer drying. Drying technology, 20(10): 1503-1513.
Ozdemir, M. and Devres, Y. O. (1999). The thin layer drying characteristics of hazel-nuts during roasting. Journal of Food Engineering, 42, 225-233
Parakash, S., Jha, S.K. and Datta, N. (2004). Performance evaluation of balanced carrots dried by three different driers. Journal of Food Engineering., 62, 305-313.
Perry, H.and D.R. Green, D.R.(1984).Perry’s chemical engineering handbook (6th ed.). New York: McGraw-Hill.
Saad, M. M., RizkS. S. and Metweally, M. N. (1992). Using the solar energy in drying of agricultural products. El-Dar El-Dawlia for Pub.And Delivering, Cairo, Egypt
Sharma,G P., Verma, R. C. and Pathare, P. (2005). Mathematical modeling of infrared radiation thin layer drying of onion slices. J. Food Eng., 71: 282–286
Shi, J., Tara, H., McHugh, D. Wood, E. Hirscberg and Olson. (2008). Drying and quality characteristics of fresh and sugar-infused blueberries dried with infrared radiation heating. LWT- Food science and Technology, 41 (10): 1962-1972
Velice, D., Planinic, M., Tomas, S. and Bilic, M. (2004). Influence of airflow velocity on kinetics of convection apple drying. Journal of Food Engineering 64 , 79-102
Workneh, T. S., Raghavan, V. and Gariepy, Y. (2011). Microwave assisted hot air ventilation drying of tomato slices. International conference on food engineering biotechnology. Singapoor.IPCBEV, vol.9, 150-162. | ||||
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