Change in dielectric properties of sweet potato during microwave drying
- 15 Downloads
Sweet potato slices and strips (thickness of 6 and 9 mm, respectively) as single layer were dried at different microwave power levels (90 W to 900 W) in order to determine the effect of microwave power and sample shape on drying characteristics. Dielectric properties of sweet potato slices were measured during microwave drying. Drying time for both samples was decreased with increase in microwave power, and drying time of strips was longer than slices in the microwave power range between 90 and 720 W. Page model was suitable for describing experimental drying data regardless of microwave power and shape of sweet potato samples. Dielectric properties of sweet potato slices were decreased with a decrease in moisture content. The change in dielectric properties of sweet potato slices could be predicted by Henderson and Pabis model and could be applied to estimate the change in moisture content of sweet potato during microwave drying.
KeywordsSweet potato Microwave drying Drying models Dielectric properties
This work was carried out with the support of the “Cooperative Research Program for Agriculture Science and Technology Development (Project No. PJ10224701)” Rural Development Administration, Republic of Korea.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
- AOAC. Official Method of Analysis. Association of Official Analytical Chemists (No. 934. 06), Arlington, VA (1990)Google Scholar
- Gorris LGM, Peppelenbos HW. Modified atmosphere and vacuum packaging to extend the shelf life of respiring food products. Horttechnology. 2(3): 303–309 (1992)Google Scholar
- Henderson SM, Pabis S. Grain drying theory I: temperature effect on drying coefficient. J. Agric. Res. Eng. 6: 169–174 (1961)Google Scholar
- Kim KB. Measurement of dielectric properties of cereal grains by nondestructive microwave measurement technique. J. Korean Soc. Nondestruct. Test. 22(4): 369–376 (2002)Google Scholar
- Nelson S, Forbus W, Lawrence K. Permittivities of fresh fruits and vegetables at 0.2 to 20 GHz. J. Microw. Power EE. 29(2): 81–93 (1994)Google Scholar
- Nelson S. Dielectric Properties of Agricultural Materials and Their Applications. Elsevier, Boston, MA (2015)Google Scholar
- Page GE. Factors influencing the maximum rates of air drying shelled corn in thin layers. M.S. thesis, Department of Mechanical Engineering, Purdue University, Purdue, USA (1949)Google Scholar
- Wang Y, Li Y, Wang S, Zhang L, Gao M, Tang J. Review of dielectric drying of foods and agricultural products. Int. J. Agric. Biol. Eng. 4(1): 1–19 (2011)Google Scholar
- Yağcıoğlu A, Değirmencioğlu A, Çağatay F. Drying characteristics of laurel leaves under different drying conditions. In: 7th Int Congress on Agricultural Mechanization and Enerdy, pp. 565–569 (1999)Google Scholar