Effects of oven, microwave and vacuum drying on drying characteristics, colour, total phenolic content and antioxidant capacity of celery slices

Main Article Content

A. Özkan Karabacak
S. Suna
C.E. Tamer
Ö.U. Çopur


celery, drying kinetics, colour, phenolics


In this research, the effects of microwave (190, 375, and 680 W) vacuum (500, 600, and 700 mbar) and oven (70, 85, and 100 °C) drying methods on the total phenolics, antioxidant capacity, colour and drying characteristics of celery slices were studied. For the selection of the most suitable thin layer drying model, five mathematical models (Page, Modified Page, Logarithmic, Lewis, and Henderson and Pabis) have been applied to the treatments. In light of the statistical tests, Page and Modified Page models were considered the best to describe drying characteristics. Regarding the colour value changes during drying, L*, ?Eab and h° decreased, and a* increased. Additionally, both b* and C*ab increased with microwave and oven drying but decreased with vacuum drying. Dried celery had 38.51-75.34% less total phenolic content than fresh samples, while its antioxidant capacities was greater. The highest ferric-reducing ability of plasma (FRAP; 49.35±3.10 ?mol TE/g dw) and cupric-reducing antioxidant capacity (CUPRAC; 33.29±1.02 ?mol TE/g dw) resulted from microwave drying at 680 W, and the highest antioxidant capacity from the DPPH method (9.87±0.04 ?mol TE/g dw) resulted from microwave drying at 375 W. In overall evaluation, microwave drying provided greater nutritional properties by increasing antioxidant capacity and gave the advantage of reduced drying times.

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Alibas, ?., 2012. Microwave drying of grapevine (Vitis vinifera L.) leaves and determination of some quality parameters [in Turkish]. Journal of Agricultural Sciences 18: 43-53.
Al-Juhaimi, F., Uslu, N., Bozkurt, D., Ghafoor, K., Babiker, E.E. and Özcan, M.M., 2016. Effects of oven and microwave drying on phenolic contents and antioxidant activities in four apple cultivars. Quality Assurance and Safety of Crops & Foods 8: 51-55.
Apak, R., Güçlü, K., Özyürek, M. and Çelik, S.E., 2008. Mechanism of antioxidant capacity assays and the CUPRAC (cupric ion reducing antioxidant capacity) assay. Microchimica Acta 160: 413-419.
Arevalo-Pinedo, A., Murr, F.E.X., Giraldo-Zuniga, A.D. and Arevalo, Z.D.S., 2004. Vacuum drying of carrot (Doucus carota): effects of pretreatments and parameters process. In: Proceedings of the 14thInternational Drying Symposium, 22-25 August, 2004, Sao Paulo, Brazil, pp. 2021-2026. Available at; http://tinyurl.com/yd2znnjl
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.
Avhad, M.R. and Marchetti, J.M., 2016. Mathematical modelling of drying kinetics of Hass avocado seeds. Industrial Crops and Products 91: 76-87.
Babalis, S.J. and Belessiotis, V.G., 2004. Influence of the drying conditions on the drying constants and moisture diffusivity during thin-layer drying of figs. Journal of Food Engineering 65: 449-458.
Benzie, I.F.F. and Strain, J.J., 1996. The ferric reducing ability of plasma (FRAP) as a measure of ‘antioxidant power’: the FRAP assay. Analytical Biochemistry 239: 70-76.
Bialobrzewsiki, I., 2006. Determination of the heat transfer coefficient by inverse problem formulation during celery root drying. Journal of Food Engineering 74: 383-391.
Celen, S., Bulus, H.N., Moralar, A., Haksever, A. and Ozsoy, E., 2016. Availability and modelling of microwave belt dryer in food drying [in Turkish]. Journal of Tekirdag Agricultural Faculty 13: 71-83.
Chu, Y.F., Sun, J., Wu, X. and Liu, R.H., 2002. Antioxidant and antiproliferative activities of common vegetables. Journal of Agricultural and Food Chemistry 50: 6910-6916.
Crozier, A., Lean, M.E.J., McDonald, M.S. and Black, C., 1997. Quantitative analysis of the flavonoid content of commercial tomatoes, onions, lettuce, and celery. Journal of Agricultural and Food Chemistry 45: 590-595.
Dadali, G., Apar, D.K. and Ozbek, B., 2007b. Microwave drying kinetics of okra. Drying Technology 25: 917-924.
Dadali, G., Demirhan, E. and Ozbek, B., 2007a. Microwave heat treatment of spinach: drying kinetics and effective moisture diffusivity. Drying Technology 25: 1703-1712.
Dadali, G., Demirhan, E. and Ozbek, B., 2007c. Color change kinetics of spinach undergoing microwave drying. Drying Technology 25: 1713-1723.
Deepa, N., Kaura, C., George, B., Singh, B. and Kapoor, H., 2007. Antioxidant constituents in some sweet pepper (Capsicum annuumL.) genotypes during maturity. LWT – Food Science and Technology 40: 121-129.
Degirmencioglu, N., Gürbüz, O., Herken, E.N. and Yurdunuseven Y?ld?z, A., 2016. The impact of drying techniques on phenolic compound, total phenolic content and antioxidant capacity of oat flour tarhana. Food Chemistry 194: 587-594.
Demiray, E. and Tülek, Y., 2014. Drying characteristics of garlic (Allium sativum L.) slices in a convective hot air dryer. Heat Mass Transfer 50: 779-786.
Demiray, E., Seker, A. and Tulek, Y., 2016. Drying kinetics of onion (Allium cepa L.) slices with convective and microwave drying. Heat Mass Transfer 53: 1817-1827.
Demirhan, E. and Ozbek, B., 2011. Thin-layer drying characteristics and modeling of celery leaves undergoing microwave treatment. Chemical Engineering Communications 198: 957-975.
Doymaz, I., 2006. Drying kinetics of black grapes treated with different solutions. Journal of Food Engineering 76: 212-217.
Fazal, S.S. and Singla, R.K., 2012. Review on the pharmacognostical and pharmacological characterization of Apium Graveolens Linn. Indo Global Journal of Pharmaceutical Sciences 2: 36-42.
Garau, M.C., Simal, S., Rossello, C. and Femenia, A., 2007. Effect of air-drying temperature on physico-chemical properties of dietary fibre and antioxidant capacity of orange (Citrus aurantium v. Canoneta) by-products. Food Chemistry 104: 1014-1024.
Geankoplis, C.J., 2011. Transport processes and unit operations. Pearson, London, UK, 1052 pp.
Gunasekaran, S., 1999. Pulsed microwave-vacuum drying of food materials. Drying Technology 17: 395-412.
Horuz, E., Bozkurt, H., Karata?, H. and Maskan, M., 2017. Effects of hybrid (microwave-convectional) and convectional drying on drying kinetics, total phenolics, antioxidant capacity, vitamin C, color and rehydration capacity of sour cherries. Food Chemistry 230: 295-305.
Ibarz, A., Pagan, J. and Garza, S., 1999. Kinetic models for colour changes in pear puree during heating at relatively high temperatures. Journal of Food Engineering 39: 415-422.
Inceday?, B., Tamer, C.E., Özcan Sinir, G., Suna, S. and Çopur, Ö.U., 2016. Impact of different drying parameters on color, ?-carotene, antioxidant activity and minerals of apricot (Prunus armeniaca L.). Food Science and Technology Campinas 36: 171-178.
Izli, N., Tamer, C.E., Copur, O.U., I??k, E. and Y?ld?z, B., 2017. Drying model of sliced apple and effect of vacuum impregnation on its physicochemical properties. Philippine Agricultural Scientist 100: 315-323.
Jezek, D., Tripalo, B., Brncic, M., Karlovic, D., Brncic, S.R., Vikic-Topic, D. and Karlovic, S., 2008. Dehydration of celery by infrared drying. Croatica Chemica Acta 8: 325-331.
Karaaslan, S.N. and Tuncer, I.K., 2008. Development of a drying model for combined microwave-fan-assisted convection drying of spinach. Biosystems Engineering 100: 44-52.
Katalinic, V., Milos, M., Kulisic, T. and Jukic, M., 2006. Screening of 70 medicinal plant extracts for antioxidant capacity and total phenols. Food Chemistry 94: 550-557.
Kaya, A., Ayd?n, O. and Kolayl?, S., 2010. Effect of different drying conditions on the vitamin C (ascorbic acid) content of Hayward kiwifruits (Actinidia deliciosa Planch). Food and Bioproducts Processing 88: 165-173.
Kaya, A., Kamer, M.S. and ?ahin, H.E., 2015. Experimental investigation of drying kinetics of Trabzon persimmon (Diospyros kaki L.) [in Turkish]. Journal of Food 40: 15-21.
Madamba, P.S. and Liboon, F.A., 2001. Optimization of the vacuum dehydration of celery (Apium graveolens) using the response surface methodology. Drying Technology 19(3-4): 611-626.
Manal, M.S.M. and Sahar, S.A., 2012. The effects of purslane and celery on hypercholesterolemic mice. World Journal of Dairy and Food Sciences 7: 212-221.
Manzocco, L., Anese, M. and Nicoli, M.C., 1998. Antioxidant properties of tea extracts as affected by processing. Lebennsmittel Wissenschaft und Technologie 31: 694-698.
Manzocco, L., Calligaris, S., Masrrocola, D., Nicoli, M.C. and Lerici, C.R., 2001. Review of non-enzymatic browning and antioxidant capacity in processed foods. Trends in Food Science & Technology 11: 340-346.
Martín-Cabrejas, M.A., Aguilera, Y., Pedrosa, M., Cuadrado, C., Hernández, T., Díaz, S. and Esteban, R., 2009. The impact of dehydration process on antinutrients and protein digestibility of some legume flours. Food Chemistry 114: 1063-1068.
Maskan, M., 2000. Microwave/air and microwave finish drying of banana. Journal of Food Engineering 44: 71-78.
Maskan, M., 2001. Kinetics of colour change of kiwifruits during hot air and microwave drying. Journal of Food Engineering 48: 169-175.
McMinn, W.A.M., 2006. Thin-layer modeling of the convective, microwave, microwave-convective and microwave-vacuum drying of lactose powder. Journal of Food Engineering 72: 113-123.
Me?ndez-Lagunas, L., Rodríguez-Ramírez, J., Cruz-Gracida, M., Sandoval-Torres, S. and Barriada-Bernal, G., 2017. Convective drying kinetics of strawberry (Fragaria ananassa): effects on antioxidant activity, anthocyanins and total phenolic content. Food Chemistry 230: 174-181.
Miranda, M., Vega-Gálvez, A., López, J., Parada, G., Sanders, M., Aranda, M., Uribe, E. and Scala, K.D., 2010. Impact of air-drying temperature on nutritional properties, total phenolic content and antioxidant capacity of quinoa seeds (Chenopodium quinoa Willd). Industrial Crops and Products 32: 258-263.
Orikasa, T., Koide, S., Okamoto, S., Imaizumi, T., Muramatsu, Y., Takeda, J., Shiina, T. and Tagawa, A., 2014. Impacts of hot air and vacuum drying on the quality attributes of kiwifruit slices. Journal of Food Engineering 125: 51-58.
Overhults, D.D., White, G.M., Hamilton, M.E. and Ross, I.J., 1973. Drying soybeans with heated air. Transactions of the ASAE 16: 195-200.
Ovodova, R.G., Golovchenko, V.V., Popov, S.V., Popova, G.Y., Paderin, N.M., Shashkov, A.S. and Ovodov, Y.S., 2009. Chemical composition and anti-inflammatory activity of pectic polysaccharide isolated from celery stalks. Food Chemistry 114: 610-615.
Ozdemir, M. and Devres, Y.O., 1999. The thin layer drying characteristics of hazelnuts during roasting. Journal of Food Engineering 42: 225-233.
Polatci, H., 2012. The effects of various drying methods on the drying time and quality of prune (Prunus Salicina L.). Journal of Agricultural Machinery Science 8: 171-178.
Popov, S.V., Markov, P.A., Nikitina, I.R., Petrishev, S., Smirnov, V.V. and Ovodova, Y.S., 2006. Preventive effect of a pectic polysaccharide of the common cranberry Vaccinium oxycoccus L. on acetic acid induced colitis in mice. World Journal of Gastroenterology 12: 6646-6651.
Popov, S.V., Popova, G.Y., Ovodova, R.G. and Ovodov, Y.S., 2005. Antiinflammatory activity of the pectic polysaccharide from Comarum palustre L. Fitoterapia 76: 281-287.
Priecina, L. and Karklina, D., 2014. Natural antioxidant changes in fresh and dried spices and vegetables. International Journal of Biological, Veterinary, Agricultural and Food Engineering 8: 480-484.
Priecina, L. and Karlina, D., 2013. Total polyphenol, flavonoid content and antiradical activity of celery, dill, parsley, onion and garlic dried in conventive and microwave-vacuum dryers. In: 2nd International Conference on Nutrition and Food Sciences, IPCBEE Vol. 53, IACSIT Press, Singapore, pp. 107-112. Available at: http://www.ipcbee.com/vol53/021-ICNFS2013-F2008.pdf.
Qu, W., Pan, Z. and Ma, H., 2010. Extraction modeling and activities of antioxidants from pomegranate marc. Journal of Food Engineering 99: 16-23.
Que, F., Mao, L., Fang, X. and Wu, T., 2008. Comparison of hot air-drying and freeze-drying on the physicochemical properties and antioxidant activities of pumpkin (Cucurbita moschata Duch.) flours. International Journal of Food Science and Technology 43: 1195-1201.
Roman, F. and Hensel, O., 2011. Effect of air temperature and relative humidity on thin-layer drying of celery leaves (Apium graveolens v a r. secalinum). CIGR Journal 13: 1-8.
Sahlin, E., Savage, G.P. and Lister, C.E., 2004. Investigation of the antioxidant properties of tomatoes after processing. Journal of Food Composition and Analysis 17: 635-647.
Sareban, M. and Souraki, A., 2016. Anisotropic diffusion during osmotic dehydration of celery stalks in salt solution. Food and Bioproducts Processing 98: 161-172.
Sarsavadiva, P., Sawhney, R., Pangavhane, D.R. and Sing, I., 1999. Drying behaviour of brined onion slices. Journal of Food Engineering 40: 219-226.
Soysal, Y. and Oztekin, S., 2001. Technical and economic performance of a tray dryer for medicinal and aromatic plants. Journal of Agricultural Engineering Research 79: 73-79.
Soysal, Y., 2004. Microwave drying characteristics of parsley. Biosystems Engineering 89: 167-173.
Spanos, G.A. and Wrolstad, R.E., 1990. Influence of processing and storage on the phenolic composition of Thompson Seedless grape juice. Journal of Agricultural and Food Chemistry 38: 1565-1571.
Šumi?, Z., Tepi?, A., Vidovi?, S., Joki?, S. and Malbaša, R., 2013. Optimization of frozen sour cherries vacuum drying process. Food Chemistry 136: 55-63.
Suna, S., Tamer, C.E., Incedayi, B., Ozcan Sinir, G. and Copur, Ö.U., 2014. Impact of drying methods on physicochemical and sensory properties of apricot pestil. Indian Journal of Traditional Knowledge 13: 47-55.
Tavakolipour, H. and Zirgani, L., 2014. Combined hot air-microwave drying methods in banana chips production. American-Eurasian Journal of Agricultural & Environmental Sciences 14: 771-776.
Thimm, J.C., Burritt, D.J., Ducker, W.A. and Melton, L.D., 2000. Celery (Apium graveolens L.) parenchyma cell walls examined by atomic force microscopy: effect of dehydration on cellulose microfibrils. Planta 212: 25-32.
Tomsone, L. and Kruma, Z., 2014. Influence of freezing and drying on the phenol content and antioxidant activity of horseradish and lovage. Foodbalt, Department of Food Technology, Faculty of Food Technology, Latvia University of Agriculture, Jelgava, Latvia.
Turkmen, N., Sari, F. and Velio?lu, S., 2005. The effect of cooking methods on total phenolics and antioxidant activity of selected green vegetables. Food Chemistry 93: 713-718.
United States Department of Agriculture (USDA), 2001. National food and nutrient analysis program. USDA Nutrient Data Laboratory, Beltsville, MD, USA.
Valadez-Carmona, L., Cortez-García, R.M., Plazola-Jacinto, C.P., Necoechea-Mondragón, H. and Ortiz-Moreno, A., 2016. Effect of microwave drying and oven drying on the water activity, color, phenolic compounds content and antioxidant activity of coconut husk (Cocos nucifera L.). Journal of Food Science and Technology 53: 3495-3501.
Vega-Gálvez, A., Scala, K.D., Rodríguez, K., Lemus-Mondaca, R., Miranda, M., López, J. and Perez-Won, M., 2009. Effect of air-drying temperature on Physico-chemical properties, antioxidant capacity, colour and total phenolic content of red pepper (Capsicum annuum L. var.Hungarian). Food Chemistry 117: 647-653.
Vitali, D., Vedrina Dragojevic, I. and Šebecic, B., 2009. Effects of incorporation of integral raw materials and dietary fibre on the selected nutritional and functional properties of biscuits. Food Chemistry 114: 1462-1469.
Wang, Z., Sun, J., Liao, X., Chen, F., Zhao, G., Wu, J. and Hu, X., 2007. Mathematical modeling on hot air drying of thin layer apple pomace. Food Research International 40: 39-46.
Westerman, P.W., White, G.M. and Ross, I.J., 1973. Relative humidity effect on the high temperature drying of shelled corn. Transactions of the ASAE 16: 1136-1139.
Yagcioglu, A., 1999. Drying technique of agricultural products [in Turkish]. Ege University, Faculty of Agriculture Publications No. 536, Bornova, Izmir, Turkey.
Yao, Y., Sang, W., Zhou, M.J. and Ren, G.X., 2010. Phenolic composition and antioxidant activities of 11 celery cultivars. Journal of Food Science 75: 9-13.
Zhu, A. and Shen, X., 2014. The model and mass transfer characteristics of convection drying of peach slices. International Journal of Heat and Mass Transfer 72: 345-351.
Zielinska, M., Zapotoczny, P., Alves-Filho, O., Eikevik, T.M. and Blaszczak, W., 2013. Al multi-stage combined heat pump and microwave vacuum drying of green peas. Journal of Food Engineering 115: 347-356.