Investigating Some Quality and Thermodynamic Parameters of Kiwifruit Thin Layer Drying in an Air Recycling Dryer Equipped with Heat Pump

Document Type : Research Paper


1 Scientific member/Department of Mechanics of Biosystems Engineering, Faculty of Crop Engineering, Sari University of Agricultural Sciences and Natural Resources

2 Biosystems Engineering, Sari Agricultural University

3 Biosystems Engineering, Sari Agricultural Unversity


Drying reduces microbial activity, increases storage time, and facilitates packaging, transportation and storage of crops by reducing weight and volume of materials. Quality indices and thermodynamic parameters are as important cases in drying food and agricultural crops. The aim of this research is investigating the effects of air recycling and heat pump on quality indices (color changes, water rehydration and pH) and thermodynamic parameters (thermal efficiency, temperature, specific power consumption, drying coefficient and convection efficiency) of kiwifruit drying. In this research, three levels of recycling (0, 50% and 100%), three drying temperatures (45, 55 and 65ºC) and two levels with and without using a heat pump were used. Results showed that by increasing recycling from 0 to 50% color changes and pH increased and from 50% to 100% both them reduced. The maximum rehydration was related to 100% recycling with heat pump. The highest temperature and specific power consumption were 73.37 and 83.57, respectively at 45 ºC, 0% recycling and heat pump off. The lowest rate of these two parameters were 14.15 and 27.01 65 ºC, recycling 100% and heat pump on. Also, results showed that drying coefficient, heat efficiency and convective had an increasing trend by using heat pump and increasing air temperature and recycling.


Main Subjects

Aktas, M.‚ Khanlari, A., Aktekeli, B. & Amini, A. (2017). Analysis of a new drying chamber for heat pump mint leaves dryer. International Journal of Hydrogen Energy, 42: 18034-18044.
Arabhosseini, A., Huisman, W., Van Boxtel, A., & Mueller, J. (2005). Modeling of the equilibrium moisture content (EMC) of tarragon (Artemisia dracunculus L.). International Journal of Food Enginering, 1(5): 32-41.
Ataei Ardestani, S. M.,  Beheshti, B.,  Sadeghi, M.  & Minaee, S. (2015). Energy analysis and kinetics of mint leaves dehydration using vibro-fluidized bed heat pump dryer. Journal of Agricultural Machinery, 5: 154-162. (In Farsi)
Ayub Hossain, M, Gottschalk, K., & Shoeb Hassan, M. (2013). Mathematical model for a heat pump dryer for aromatic plant. Procedia Engineering, 56: 510-520.
Cernisev, S. (2010). Effect of conventional and multistage drying processing on non-enzymatic browning in tomato. Journal of Food Engineering, 96: 114-118.
Chapchaimoh, K., Poomsa, N., Wiset, L., & Morris, J. (2016). Thermal characteristics of heat pump dryer for ginger drying. Applied Thermal Engineering 95: 491–498.
Chin, S. K., Siew, E. S., & Soon, W. L. (2015). Drying characteristics and quality evaluation of kiwi slices under hot air natural convective dryer. International Food Research Journal 22: 2188-2199.
Du G., Li M., Ma F., & Liang D. (2009). Antioxidant capacity and the relationship with polyphenol and vitamin C in Actinidia fruits. Food Chemistry, 113: 557-562.
Esmaeili Adabi, E., Mousavi, S.R., Kalantary, D. & Taghvazade, A. (2016). Evaluation of some changes in quality properties of Aleo vera in a hot air dryer. Journal of Iran Food Science and Technology, 54: 85-93. (In Farsi)
Falade, K. O., Igbeka, J. C. & Ayanwuyi, F. A. (2006). Kinetics of mass transfer and color changes during osmotic dehydration of watermelon. Journal of Food Engineering, 80: 979–985.
Fennema, A., C.M. (1998). Food Chemistry. Academic Press. Second edition, New York.
Ferguson A.R., & Ferguson L.R. (2003). Are kiwifruit really good for you?. Acta Hortic, 610: 131-138.
Hansman, C.F. & Joubert, E. (1998). Dehydration of peaches without sulfur dioxide. Driying Technology, 16:101-121.
ISIRI (2016). Iranian National Standard, No. 3475.
Jafarian, H., Tabatabaekoloor, R., & Mousavi, S.R. (2017). Effects of different drying conditions on powder density and rehydration characteristics of coriandrum. Journal of Biosystem Engineering, 48: 191-199. (In Farsi)
Kaya, A., Aydin, O., & Kolayli, S. (2010). Effect of different drying conditions on the vitamin C content of Hayward kiwifruits. Food and Bioproducts Processing, 88: 165-173.
Khalili, S. E., & M. Esmaeili (2011). Effect of mechanical properties on texture and quality indices of dried kiwifruit by hot air, osmosis and microwave drying methods. Master thesis in Food Sciences and Technology, Uromia University, Urumia, Iran. (in Farsi)
Kuzgunkaya, E. H., & A. Hepbasli. (2007). Exergetic performance assessment of a ground-source heat pump drying system. International Journal of Energy Research, 31: 760-777.
Mortezapour, H., Ghobadian, B., Khoshtaghaza, M. H., & Minaei, S. (2014). Drying kinetics and quality characteristics of saffron dried with a heat pump assisted hybrid potovoltaic-thermal solar dryer. Journal of Agricultural Sciences and Technology, 16: 33-45.
Okos, M.R., Narsimhan, G., Ingh, R. K., & Weitmauer, A.C. (1992). Food dehydration. In D. R. Heldman & D. B. Lund (Eds.), Hand book of food engineering (pp. 339-382). New York:Marcel Dekker.
Madhlopa, A., Jones, S.A. & Kalenga Saka J.D. (2002). A solar air heater with composite absorber systems for food dehydration. Renewable Energy. (27): 27–37.
Maskan, M. 2001. Drying, shrinkage and rehydration characteristics of kiwifruits during hot air and microwave drying. Journal of Food Engineering, 48:177-182.
Morton, J. 2011. Kiwifruit: Actinidia deliciosa In: Fruits of Warm Climates, 1978. Center for New Crop & Plant Products at Purdue University. Retrieved 8 April 2014.
Motevali, A., Keyani, D., & Hashemi, S.J. (2017). Investigation of thermodynamic parameters and essentioan oil content in drying of rosemary by applying a microwave pulsed pretreatment. Journal of Engineering Management. 7 (2): 42-51.
Orikasa, T., Koide, S., Okamoto, S., Imuizumi, T., Maramatsu, Y., Takeda, J. & Tagawa, A. (2014). Impacts of hot air and vacuum drying on the physical and quality attributes of kiwifruit slices. Journal of Food Engineering, 125:51-58.
Pal, U., Khan,M., & Mohanty, S.(2008). Heat pump drying of green sweet pepper. Drying Technology, 26: 1584-1590.
Sahoo N. R., Pal, U. S., Dash S. K., & Khan M. K. (2012). Drying kinetics and quality aspects during heat pump drying of onion (Allium cepa L.). International Journal of Food Studies, 1: 159-167.
Şevik, S., Aktaş, M., Doğan, H., & Koçak, S. (2013). Mushroom drying with solar assisted heat pump system. Energy Conversion and Management, 72, 171-178.
Shulka BD & Singh SP. (2007). Osmo-convective drying of cauliflower, mushroom and green pea. Journal of Food Engineering, 80: 741-747.
Sjoholm, I., & Gekas, V. 1995. Apple shrinkage upon drying. Journal of Food Engineering, 25: 123-130.
Tavarini S., Degl’Innocenti E., Remorini D., Massai R., & Guidi L. 2008. Antioxidant capacity, ascorbic acid, total phenols and carotenoids changes during harvest and after storage of Hayward kiwifruit. Food Chemistry, 70: 282-288.
Vieira, M.G.A., Estrella, L., &Rocha, S.C.S. (2007). Energy efficiency and drying kinetics of recycled paper pulp. Drying Technology, 25:1639-1648.
Walker, H. T. 1992. Drying Cut Fruits with Recirculated Air for Energy Savings. The Master Thesis. The University of Tennesse, Knoxville, TN.
Zakipour-Molkabadi, E., Hamidi-Esfahani Z., & Abbasi S. (2011) Formulation of Leather from Kiwi Fruit Losses. Iran Food Sciences and Technology Research Journal, 6 (4): 263-270. (In Farsi)
Zargari A. (1992). Medicinal Herb. Vol.3-Tehran Publication.
Zomorodian, A. (2004). Grain Drying (Theoretical and practical). Agriculture Science Publication, Tehran, Iran.