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Empirical Study of the Energy Demand and Drying Behaviour of Selected Tuber Crops
Subject area: Science,Engineering and Technology · Area of research: Agricultural and Bio-systems Engineering
Abstract
This study investigated the persistent challenge of post-harvest losses in selected tuber crops, namely white yam (Dioscorea rotundata), trifoliate yam (Dioscorea dumetorum), and cocoyam (Xanthosoma sagittifolium), which are staple crops of major nutritional and economic significance in Nigeria. This research empirically characterised the drying behaviour and energy demand of white yam, trifoliate yam, and cocoyam under microwave oven drying conditions. Specific objectives included evaluating the effects of key process parameters—temperature (40, 45, 50 °C), air velocity (2, 3, 4 m/s), and slice thickness (3, 4, 5 mm)—on drying kinetics, energy efficiency, product shrinkage, effective moisture diffusivity, and activation energy. The study assessed the performance of ten thin-layer drying models to determine the most appropriate for describing tuber drying behaviour under microwave conditions. Findings revealed that drying occurred predominantly within the falling rate period. Cocoyam exhibited the fastest drying rate and highest effective diffusivity, while trifoliate yam showed the slowest moisture removal. Increased temperature, elevated air velocity, and reduced slice thickness significantly enhanced drying efficiency. Optimal conditions were achieved at 45°C and 3 m/s. Among the tested models, the Midilli et al. model consistently provided the best fit, with R² values exceeding 0.988. The study concludes that microwave drying is highly effective for selected tubers, with performance critically dependent on process parameters, and that microwave oven drying is highly effective for selected tubers, with performance critically dependent on process parameters. The study, therefore recommends 50 °C, 4 m/s, and 3 mm slicing for industrial use, and proposes further research into nutritional retention and the validation of the Specific Thin-Layer Drying Model for Yam Tubers (STLDMYT).
Keywords
Tuber Crops, Energy Demand, Microwave Dryers, Drying Behaviour, Drying Efficiency.
References
[1] O. A. Abiodun, R. Akinoso. Physical and functional properties of trifoliate yam flours as affected by harvesting periods and pretreatment methods. J Food Process Technol. 2014, 5(2), 302.
[2] T. J. Afolabi, T.Y. Akintunde, and O.J. Oyelade. Influence of drying conditions on the effective moisture diffusivity and energy requirements of ginger slices. Journal of Food Research, 2014, 3(5):103–112.
[3] S.J. Babalis and V.G. Belessiotis. Influence of the drying conditions on the drying constants and moisture diffusivity during the thin layer drying of figs, Journal of Food Engineering, 2004, 65(1): 449-458.
[4] J. M. Cardoso & R. Da Silva Pena. Hygroscopic behaviour of banana (Musa ssp. AAA) flour in different ripening stages. Food and bioproducts processing, 2014, 92(1), 73-79.
[5] I. Ceylan, M. Aktas and H. Dog˘an. Mathematical modeling of drying characteristics of tropical fruits. Applied Thermal Engineering 27: 2007, 1931-1936.
[6] X., Chen, X. Li, X. Mao, H. Huang. Effects of drying processes on starch-related physicochemical properties, bioactive components and antioxidant properties of yam flours. Food Chem.2017, 224, 224–232.
[7] H. Darvishi, A.R. Asl, A. Asghari, M. Azadbakht, G. Najafi and J. Khdaei. Study of the drying kinetics of pepper. Journal of the Saudi Society of Agricultural Sciences, 2013a, Vol. 13(2), pp. 130-138.
[8] H. Darvishi, A.R. Asl, Asghari, G. Najafi and H.A. Gazori, Mathematical modeling, moisture diffusion, energy consumption and efficiency of thin layer drying of potato slices. J. Food Process Technol, 2013b, 4:215.
[9] H. Darvishi, A.R. Asl, A. Asghari, G. Najafi & H.A. Gazori. Mathematical modeling, moisture diffusion, energy consumption and efficiency of thin-layer drying of potato slices: Journal of Food Process Technology, 2013, 4 (3), 215 – 229.
[10] I. Doymaz, Thin-layer drying characteristics of sweet potato slices and mathematical modeling. Heat Mass Transfer 2011, 47, 277–285.
[11] N.R. Nwakuba, S.N. Asoegwu, & K.N Nwaigwe. Energy requirements for drying of sliced agricultural products: a review. Agricultural Engineering International: CIGR Journal, 2016, 18(2):144-155.
[12] N.R., Nwakuba, S.N., Asoegwu, K.N., Nwaigwe, & C.O. Chukwuezie, Design and development of a hybrid solar-electric dryer for sliced vegetable crops. Journal of Agricultural Engineering and Technology. 2017, 23(2): 48 – 56.
[13] N.R. Nwakuba, O.C. Chukwuezie, G.U. Asonye and S.N. Asoegwu. Energy analysis and optimization of thin layer drying conditions of okra. Arid zone journal of engineering, technology and environment (AZOJETE). Innovation & Technologies for Sustainable Agricultural Production & Food Sufficiency. 2018, Vol. 14 (SP. i4): 135-154
[14] J.O. Ojediran, A.O. Raji. Thin layer drying of millet and effect of temperature on drying characteristics. Int. Journal. Food Res. Technology, 2010, 17, 1095–1106.
[15] K.O. Falade, N.F. Onyeoziri. Effects of cultivar and drying method on color, pasting and sensory attributes of instant yam (Dioscorea rotundata) flours. Food Bioprocess Technology, 2012, 5, 879–887.
[16] A. Motevali, S. Younji, R.A. Chayjan, N. Aghilinategh, & A. Banakar, (2013). Drying kinetics of dill leaves in a convective dryer. International Agrophysics Journal, 2013, pp. 27, 39-47.
[17] G. Yildiz and G. İzli. Influence of microwave and microwave‐convective drying on the drying kinetics and quality characteristics of pomelo. J Food Process Preserv; 2018, 43(6), pp. 1 – 11.
[18] A. Yagcioglu, A. Degirmencioglu & F. Cagatay. Drying Characteristics of Laurel Leaves under different conditions. In: Basecetincelik A, editor. Proceedings of the seventh International Congress on Agricultural Mechanization and Energy. Adana, Turkey: Faculty of Agriculture, Cukurova University; 1999. Pp. 565-569.
[19] M.N. Haque and T.A.G. Langrish, T. A. G. Assessment of the Actual Performance of an Industrial Solar Kiln for Drying Timber. Drying Technology 2005. 23: 1541-1553.
[20] A. Upadhyay, H.K. Sharma, and B.C. Sharkar. Characterization and Dehydration Kinetics of Carrot Pomace. Agricultural Engineering International: The CIGR Ejournal. Manuscript 2008, Vol. 10. FP 07 35. Pp. 1 – 9.
[21] Hall, C.W. (1990). Drying and storage of agricultural crops. The AVI Publishing Co., Westport, Connecticut. Pg 237.
[22] B. O¨zbek and G. Dadali. Thin-layer drying characteristics and modeling of mint leaves undergoing microwave treatment. Journal of Food Engineering. 2007, 83: 541-549.
[23] M.R. Okos, G. Narsimhan, R.K. Singh & A.C. Witnauer. Food dehydration. In: Handbook of food Engineering, Mercel-Dekker Inc., NY:1992, 437-562.
[24] R. K. Goyal, A.R.P. Kingsly, M.R. Manikantan & S.M. IIyas. Thin-layer drying kinetics of raw mango slices. Journal of food Engineering, 2014, 74, 92 – 95.
[25] T.I. T. Koyuncu and Y. Pinar. Drying characteristics and heat energy requirement of cornelian cherry fruits (Cornus mas L.). Journal of Food Engineering, 2007, 78:735 - 739.
[26] S. Minaei, H.A. Cheuarbon, A. Motevali and A. Arabhosseim. Energy consumption, thermal utilization efficiency and hypericum content in drying leaves of St. John’s wort. Journal of Energy in Southern Africa, 2014, 25(3):27-35.
[27] S. Raju. Strategies for enhancing post-harvest quality and shelf life of tuber crops: Insights from physiological perspectives. Journal of Root Crops, 2021, 47(1 & 2), 40-52.
[28] A.A. Okunola, T.A. Adekanye, C.E. Okonkwo, M. Kaveh, M. Szymanek, E.O. Idahosa, A.T. Olayanju, & K. Wojciechowska. Drying Characteristics, Kinetic Modeling, Energy and Exergy analyses of water yam (Dioscorea alata) in a hot air dryer. Energies, 2023, 16(4), 1569.
[29] I. Doymaz, I. Thin-layer drying behaviour of mint leaves. Journal of Food Engineering, 2006, 74:370-375.
[30] N.A. Akgun and I. Doymaz. Modelling of Olive cake thin-layer drying process. Journal of Food Engineering. 2005, 68(4), Pp. 455-461.
[31] V. Kumar, H.K. Sharma & K. Singh, K. Mathematical modeling of thin layer microwave drying of taro slices. Journal of the Institution of Engineers (India): Series A, 2016, 97(1), 53-58.
[32] O.Y. Turan, F.E. Firatligil. (2019). Modeling and characteristics of thin-layer convective air-drying of thyme (Thymus vulgaris) leaves. Czech J. Food Sci., 2019, 37: 128-134.
How to cite this paper
@article{1714907,
author = {Paul Ikechukwu Ehumadu , Professor Kingsley Ogueri Chilakpu, Dr. Nnaemeka Reginald Nwakuba, Dr. Gladys Uche Asonye},
title = {Empirical Study of the Energy Demand and Drying Behaviour of Selected Tuber Crops},
journal = {Iconic Research And Engineering Journals},
year = {2026},
volume = {9},
number = {9},
pages = {577-594},
issn = {2456-8880},
url = {https://www.irejournals.com/formatedpaper/1714907.pdf},
abstract = {This study investigated the persistent challenge of post-harvest losses in selected tuber crops, namely white yam (Dioscorea rotundata), trifoliate yam (Dioscorea dumetorum), and cocoyam (Xanthosoma sagittifolium), which are staple crops of major nutritional and economic significance in Nigeria. This research empirically characterised the drying behaviour and energy demand of white yam, trifoliate yam, and cocoyam under microwave oven drying conditions. Specific objectives included evaluating the effects of key process parameters—temperature (40, 45, 50 °C), air velocity (2, 3, 4 m/s), and slice thickness (3, 4, 5 mm)—on drying kinetics, energy efficiency, product shrinkage, effective moisture diffusivity, and activation energy. The study assessed the performance of ten thin-layer drying models to determine the most appropriate for describing tuber drying behaviour under microwave conditions. Findings revealed that drying occurred predominantly within the falling rate period. Cocoyam exhibited the fastest drying rate and highest effective diffusivity, while trifoliate yam showed the slowest moisture removal. Increased temperature, elevated air velocity, and reduced slice thickness significantly enhanced drying efficiency. Optimal conditions were achieved at 45°C and 3 m/s. Among the tested models, the Midilli et al. model consistently provided the best fit, with R² values exceeding 0.988. The study concludes that microwave drying is highly effective for selected tubers, with performance critically dependent on process parameters, and that microwave oven drying is highly effective for selected tubers, with performance critically dependent on process parameters. The study, therefore recommends 50 °C, 4 m/s, and 3 mm slicing for industrial use, and proposes further research into nutritional retention and the validation of the Specific Thin-Layer Drying Model for Yam Tubers (STLDMYT).},
keywords = {Tuber Crops, Energy Demand, Microwave Dryers, Drying Behaviour, Drying Efficiency.},
month = {March},
doi = {https://doi.org/10.64388/IREV9I9-1714907}
}