Effects of drying process on qualitative and quantitative properties of watercress (Nasturtium officinale) leaves

Document Type : Research Article


1 Graduated student, Department of Food and Science Technology, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran

2 Associate Professor, Department of Chemistry, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran


This study has investigated the effects of different drying methods on qualitative and quantitative characteristics of watercress (Nasturtium officinale) leaves, including water loss, antioxidant activity, contents of vitamin C, phosphorus, calcium, and iron. Hot air oven dryer at three thermal levels (40, 50 and 60 °C), microwave dryer at the three powers (180, 360 and 450 W) and the sun were used for drying of the leaves. In terms of drying time, the longest and shortest times were related to the dried treatments with the sun (1920 min) and the microwave at 450 W (22 min), respectively. In the charts related to moisture loss rate of the product, there was a period of constant speed and a term with the falling speed of moisture loss. Drying rate was increased by increasing microwave power and temperature of hot air oven, but the drying time was decreased. In the sun method, drying was performed at a slower rate due to temperature fluctuations. The highest amounts of vitamin C, iron and calcium were obtained to the dried samples by the oven at 60 °C (6.9 mg.100g), the sun (519.8 ppm) and the microwave at 180 W (210.68 g/kg), respectively. Also, the highest content of phosphorus was achieved to the drying by oven at 40 °C (0.523 percent). Overall, the dried treatments by oven and microwave dryers due to less moisture contents in a constant weight than the dried treatments by the sun, more mineral contents were preserved. The most antioxidant activity was belonged to the dried treatment by the microwave at 360 W. According to the results, it can be said that drying watercress by oven at 40 °C and microwave at 180 W is more desirable, since the amount of active ingredients in the plant is preserved substantially compared to the other treatments.


Main Subjects

[1] Azizi, M., Rahmati, M., Ebadi, T., Hasanzadeh khayyat, M. (2009). The effects of different drying methods on weight loss rate, essential oil and chamazolene contents of chamomile (Matricaria recutita) flowers.  Iranian J. Med. Aromat. Plants, 25(2), 182-192 [in persion].
[2] Rezaei, K., Niakosari, M. (2008). Study of the drying process plant with two methods including hot air and freeze dryer. 18th International Congress on Food Science & Technology, 6(1), 57-68.
[3] Ebadi, T., Rahmati, M., Azizi, M., Hasanzadeh khayyat, M. (2009). Effects of different drying me
thods (natural method, oven and microwave) on drying time, essential oil content and composition of Savory (Satureja hortensis L.). Iranian J. Med. Aromat. Plants, 26(4), 477-489 [in persion].
[4] Krulis, M., Kuhnert, S., Leiker, M., Rohm, H. (2005). Influence of energyinput and initial moisture on physical properties of microwave vacuum dried strawberries. Eur. Food Res. Technol., 221, 803-808.
[5] Mirheydar, H. (1385). Plant Sciences, Islamic Culture Publications Office – Tehran, 8(8).
[6] Hecht, S.S., Chung, F.L., Richie, J.P. Jr., Akerkar, S.A., Borukhova, A., Skowronski, L., Carmella, S.G. (1995). Effects of watercress consumption on metabolism tabaco-specific lung carcinogen in smokers. Cancer Epidemiol. Biomarkers Prev., 4(8), 877-884.
[7] Yanbalagh, D., Noori Bigdeli, H. (1394). Comparison of dried apple production by solar dryer and drying with hot air (oven). First National Conference on Agricultural and Environmental Sciences Iran, Ardabil Research Center of the Earth cave, 8 p.         
[8] Nasrollahi, F., Esmaeeli, M. (1393). Effect of drying on quality Pear sheet of Sardasht. The first national conference between meals. Institute of Food Science and Technology Research Mashhad, Mashhad, 8 p.
[9] Mehdinejad Shanii, M., Arabshahi Dolouee, S., Fadavi, A. (1393). Study of antioxidant properties different extracts of Watercress (NasturtiumOfficinale L). The Second National Conference of Medicinal Plants and Sustainable Agriculture, Hamedan, 21 p.
[10] Oztekin, S., Martinov, M. (2007). Medicinal and aromatic crops: harvesting, drying, and processing. CRC Press, p 320.
[11] Diamante, L.M., Munro, P.A. (1991). Mathematical modeling of the thin layer solar drying of sweet potato slices. Sol. Energ., 51, 271-276.
[12] Institute of Standards and Industrial Research of Iran. (1380) Friuts, Vegetables and Derived Products Determination of Ascorbic Acid (Vitamin C)-(Routine method), 1st Edition, Isiri number 5609.
[13] Institute of Standards and Industrial Research of Iran. (1381). Cereal and cereal products-determination of iron by atomic absorption spectrophotometry, 1st Edition, Isiri number 5539.
[14] Institute of Standards and Industrial Research of Iran. 1386. Animal feeding stuffs–determination of calcium content – Part 1: Titrimetric method, 1st Edition, Isiri number 10701-1.
 [15] Institute of Standards and Industrial Research of Iran. (1386). Meat and meat products determination of total phosphorus content - Spectrometric method, Second Revision, Isiri number 1134.
[16] Blois, M.S. (1958). Antioxidant determination by the use of a stable free radical. J. Nat., 26, 1199-1200.
[17] Noori, M., Kashaninejad, M., Daraei Garme Khani, A., Bolandi, M. (1391). Optimization of drying process of parsley using the combination of hot air and microwave methods. J. Food Process. Preser., 4 (2), 103-122 [in persion].
[18] Bagheri, H., Seiedabadi, M., Kashaninejad, M. (1393). Kinetic modeling of thin layer drying of kammeh (local curd). J. Food Sci. Tech., 2(5), 3-16 [in persion].
[19] Khafajeh, H., Banakar, A., Minaei, S., Taghizadeh, A., Motavali, A., Rezaei Aderyani, M. (1393). Investigation of energy consumption and drying kinetics of thyme leaves in microwave dryer. J. Food Sci. Tech., 45(11), 45-54 [in persion].
[20] Akpinar, K.., Bicer, Y., Cetinkay, F. (2006). Modelling of thin layer drying of parsley leaves in a convective dryer and under open sun. J. Food Eng., 3, 308-315.
[21] Ozbek, B., Dadali, G. (2007). Thin-layer drying characteristics and modelling of mint leaves undergoing microwave treatment. J. Food Eng., 4, 541-549.
[22] Seiiedlou, S., Ghasemzadeh, H., Hamdamii, N. (1392). Modeling of apple slices shrinkage during the convectional drying to use in simulation of heat and moisture transfer. J. Agricultural Mechanization, 1(2), 25-35 [in persion].
[23] Doymaz, I. (2011). Prediction of drying characteristic pomegranate arils. J. Food Eng., 19(2), 741-749. 
[24] Hevia, F., Melin, P., Berti, M., Fischer, S., Pinichet, C. (2002). Effect of drying temperature and air speed on cichoric acid and alkylamide content of Echinaceae purpurea. Acta Hortic., 576, 321-325.       
[25] Funebo, T., Ohlsson, T. (1998). Microwave-assisted air dehydration of apple and mushroom. J. Food Eng., 38, 353-367.
[26] Maskan, M. (2000). Microwave/air and microwave finish drying of banana. J. Food Eng., 48, 169-175.
[27] Sharma G.P., Prasad S. (2001). Drying of garlic (Allium sativum) cloves by microwave-hot air combination. J. Food Eng., 50, 99-105.
[28] Shaabani, B., Tavakolipoor, H. (1391).  Mathematical modeling of drying kinetics of a thin layer of bell pepper. J. Food Sci. and Tech. 4(4), 33-42 [in persion].
[29] Asekan, O.T., Grieson, D.S., Afolayan, A.J. (2007). Effect of drying methods on the quality the essential oil of Mentha lonifolia L. subsp Capensis. Food Chem., 101, 995-998.   
[30] Yektakhah, S., Mirzaei, H. (1393). The effect of drying method on some quality properties and organoleptic of dates. Third National Conference on Food Science and Technology, Ghoochan, Islamic Azad University, Quchan Branch, 6 p.
[31] a) Ozcan, M.M., Arsalan, D. (2008). Evaluation of drying methods with respect to drying kinetics, mineral content and colour characteristics of rosemary leaves. Energ. Convers. Manag. J., 49(5), 1258-1264; b) Ozcan, M.M., Arsalan, D., Ahmet, U. (2005). Effect of drying methods on the mineral content of basil (Ocimum basilicum L.). J. Food Eng., 69, 375-379.
[32] Akbari, A., SHahedi, M., Hmadami, N., Dokhani, S., Sadeghi, M. (2009). Study of water loss kinetics and quality characteristics of the tomato slices during drying by three methods: solar drying, open-sun drying and hot air drying. JWSS - Isfahan University of Technology, 13(47), 445-459.
[33] Moslemi, M., Mirzaei, H. (1393). Comparison of hot air and microwave drying on the quality characteristics of apricot, Third National Conference on Food Science and Technology, Ghoochan, Islamic Azad University, Quchan Branch, 10 p.
[34] Sarabiar, S., Tahmasbi, H.A., Zare Aliabadi, H. (1393). The effect of microwave radiation on the amount of vitamin C IN Kiwi sheets dried in the microwave and residual moisture in it. Third National Conference of Food Science and Technology, Ghoochan, Islamic Azad University, Quchan Branch, 4 p.
[35] Ghamargir, S., Seyyed Alangi, S.Z. (1393). Optimization of pring of Mentha Longifolia. Master's thesis in chemical engineering food industry, Islamic Azad University, Azadshahr Branch.