All Issue

2018 Vol.43, Issue 3 Preview Page
September 2018. pp. 237-246

Purpose: This study (a) investigated the effect of microwave power intensity and sample thickness on microwave drying characteristics of radish strips, and (b) determined the best-fit drying model for describing experimental drying data, effective moisture diffusivity (Deff), and activation energy (Ea) for all drying conditions. Methods: A domestic microwave oven was modified for microwave drying and equipped with a small fan installed on the left upper side for removing water vapor during the drying process. Radishes were cut into two fixed-size strip shapes (6 and 9 mm in thickness). For drying experiments, the applied microwave power intensities ranged from 180 to 630 W at intervals of 90 W. Six drying models were evaluated to delineate the experimental drying curves of both radish strip samples. The effective moisture diffusivity (Deff) was determined from Fick’s diffusion method, and the Arrhenius equation was applied to calculate the activation energy (Ea). Results: The drying time was profoundly decreased as the microwave power intensity was increased regardless of the thickness of the radish strips; however, the drying rate of thicker strips was faster than that of the thinner strips up to a certain moisture content of the strip samples. The majority of the applied drying models were suitable to describe the drying characteristics of the radish strips for all drying conditions. Among the drying models, based on the model indices, the best model was the Page model. The range of estimated Deff for both strip samples was from 2.907 × 10−9 to 1.215 × 10−8 m2/s. Ea for the 6- and 9-mm strips was 3.537 and 3.179 W/g, respectively. Conclusions: The microwave drying characteristics varied depending on the microwave power intensity and the thickness of the strips. In order to produce high-quality dried radish strips, the microwave power intensity should be lower than 180 W.

  1. Alibas, I. 2014. Mathematical modeling of microwave dried celery leaves and determination of the effective moisture diffusivities and activation energy. Food Science and Technology 34(2): 394-401.
  2. Arikan, M. F., Z. Ayhan, Y. Soysal and O. Esturk. 2012. Drying characteristics and quality parameters of microwave-dried grated carrots. Food and Bioprocess Technology 5(8): 3217-3229.
  3. Baysal, T., F. Icier, S. Ersus and H. Yıldız. 2003. Effects of microwave and infrared drying on the quality of carrot and garlic. European Food Research and Technology 218(1): 68-73.
  4. Dadali, G., D. K. Apar and B. Özbek. 2007. Estimation of effective moisture diffusivity of okra for microwave drying. Drying technology 25(9): 1445-1450.
  5. Darvishi, H. 2012. Energy consumption and mathematical modeling of microwave drying of potato slices. Agricultural Engineering International: CIGR Journal 14(1): 94-102.
  6. El-Beltagy, A., G. R. Gamea and A. H. Amer Essa. 2007. Solar drying characteristics of strawberry. Journal of Food Engineering 78(2): 456-464.
  7. Henderson, S. M. and S. Pabis. 1961. Grain drying theory. II. Temperature effects on drying coefficients. Journal of Agricultural Engineering Research 6(4): 169-174.
  8. Harish, A., B. S. Vivek, R. Sushma, J. Monisha and T. P. Krishna Murthy. 2014. Effect of microwave power and sample thickness on microwave drying kinetics elephant foot yam (Amorphophallus Paeoniifolius). American Journal of Food Science and Technology 2(1): 28-35.
  9. Karathanos, V. T. 1999. Determination of water content of dried fruits by drying kinetics. Journal of Food Engineering 39(4): 337-344.
  10. Kim, J. N., Y. H. Park, Y. Y. Noh, Y. Kim and M. S. Kang. 2015. Quality characteristics of dried shredded radish and stir-fry dried shredded radish by different drying methods. Korean Journal of Food and Cookery Science 31(5): 596-604 (In Korean, with English abstract).
  11. Lee, J. H. and H. J. Kim. 2009. Vacuum drying kinetics of Asian white radish (Raphanus sativus L.) slices. LWT-Food Science and Technology 42(1): 180-186.
  12. Madamba, P. S., R. H. Driscoll and K. A. Buckle. 1996. The thin-layer drying characteristics of garlic slices. Journal of Food Engineering 29(1): 75-97.
  13. Maskan, M. 2001. Drying, shrinkage and rehydration characteristics of kiwifruits during hot air and microwave drying. Journal of Food Engineering 48(2): 177-182.
  14. Meziane, S. 2011. Drying kinetics of olive pomace in a fluidized bed dryer. Energy Conversion and Management 52(3): 1644-1649.
  15. Motevali, A., A. Abbaszadeh, S. Minaei, M. H. Khoshtaghaza and B. Ghobadian. 2012. Effective moisture diffusivity, activation energy and energy consumption in thin-layer drying of Jujube (Zizyphus jujube Mill). Journal of Agricultural Science and Technology 14(3): 523-532.
  16. O’Callaghan, J. R., D. J. Menzies and P. H. Bailey. 1971. Digital simulation of agricultural dryer performance. Journal of Agricultural Engineering Research 16(3): 223-244.
  17. Orsat, V., V. Changrue and G. V. Raghavan. 2006. Microwave drying of fruits and vegetables. Stewart Postharvest Review 2(6): 1-7.
  18. Paengkanya, S., S. Soponronnarit and A. Nathakaranakule. 2015. Application of microwaves for drying of durian chips. Food and bioproducts processing 96: 1-11.
  19. Page, G. 1949. Factors influencing the maximum rates of air-drying shelled corn in thin layer. Unpublished MS thesis. West Lafayette, Indiana: Department of Mechanical Engineering, Purdue University.
  20. Pu, Y. Y. and D. W. Sun. 2017. Combined hot-air and microwave-vacuum drying for improving drying uniformity of mango slices based on hyperspectral imaging visualisation of moisture content distribution. Biosystems Engineering 156: 108-119.
  21. Sharma, G. P. and S. Prasad. 2004. Effective moisture diffusivity of garlic cloves undergoing microwave- convective drying. Journal of Food Engineering 65(4): 609-617.
  22. Sharma, G. P., Verma, R. C. and Pathare, P. 2005. Mathematical modeling of infrared radiation thin layer drying of onion slices. Journal of food engineering, 71(3): 282-286.
  23. Soysal, Y. 2004. Microwave drying characteristics of parsley. Biosystems engineering 89(2): 167-173.
  24. Wang, J., Y. S. Xiong and Y. Yu. 2004. Microwave drying characteristics of potato and the effect of different microwave powers on the dried quality of potato. European Food Research and Technology 219(5): 500-506.
  25. Wang, Z., J. Sun, X. Liao, F. Chen, G. Zhao, J. Wu and X. Hu. 2007. Mathematical modeling on hot air drying of thin layer apple pomace. Food Research International 40(1): 39-46.
  26. Yan, W. Q., M. Zhang, L. L. Huang, A. S. Mujumdar and J. Tang. 2013. Influence of microwave drying method on the characteristics of the sweet potato dices. Journal of Food Processing and Preservation 37(5): 662-669.
  27. Yagcioglu, A., A. Degirmencioglu and F. Cagatay. 1999. Drying characteristic of laurel leaves under different conditions. In: Proceedings of the 7th international congress on agricultural mechanization and energy, pp. 565-569, Adana, Turkey.
  28. Zarein, M., S. H. Samadi and B. Ghobadian. 2015. Investigation of microwave dryer effect on energy efficiency during drying of apple slices. Journal of the Saudi Society of Agricultural Sciences 14(1): 41-47.
  • Publisher :The Korean Society for Agricultural Machinery
  • Publisher(Ko) :한국농업기계학회
  • Journal Title :Journal of Biosystems Engineering
  • Journal Title(Ko) :바이오시스템공학
  • Volume : 43
  • No :3
  • Pages :237-246
  • Received Date :2018. 07. 31
  • Accepted Date : 2018. 08. 22