The Determination of Physicomechanical Properties of Nettle Seed (Urtica pilulifera) and Optimization of Its Mucilage Extraction Conditions using Response Surface Methodology

Document Type : Original Paper


1 MSc. Student, Department of Food Science and Technology, Ferdowsi University of Mashhad, Mashhad, Iran

2 Professor, Department of Food Science and Technology, Ferdowsi University of Mashhad, Mashhad, Iran

3 Assistant Professor, Department of Biology, Payame Noor University, Tehran, Iran


In this study, some geometrical, gravimetrical and frictional properties of nettle seed were evaluated for the first time. The length, width and thickness of seeds were 2.49, 1.98 and 0.78 mm, and the average arithmatic diameter, average geometric diameter, sphericity and surface area of nettle seeds were, respectively, 1.75, 1.29 mm, 0.52 and 5.31 mm2. The true density, bulk density and porosity of nettle seeds were 1168.12, 457.19 kg/m3 and 60.86%, respectively, and the static friction coefficient on the plywood surface, glass, rubber, fiberglass and galvanized iron were 0.28, 0.21, 0.34, 0.22 and 0.27, respectively. Then, using the response surface method, the optimal conditions for extracting nettle mucilage as a new source of hydrocolloids were determined by achieving maximum seed surface ratio, extraction yield, and viscosity. Face central composite design analysis of the effect of three independent variables, including soaking temperature (25-60 °C), soaking time (0.5-4 h) and water to seed ratio (1:20-1:60), was studied. The ANOVA results showed that the quadratic polynomial model was the best model for interpreting the behavior of the three responses. Statistical analysis of the data showed that extraction yield and viscosity were significantly affected by all independent variables (p < /em><0.05), while the effect of temperature on seeds surface ratio was not significant (p < /em>>0.05). Based on the numerical optimization method, optimized conditions for extraction of nettle seed gum were determined in terms of soaking temperature of 59 °C, soaking time of 3.4h (204 min) and water to seed ratio of 1:40. Under the optimum conditions, the seeds surface ratio, extraction yield and viscosity values were obtained as 2.39, 9.70% and 6.25 mPa/s, respectively. The results of this study are of practical value for designing post-harvesting and processing equipments for nettle seeds as well as extracting mucilage from the seeds.


Amin, A. M., Ahmad, A. S., Yin, Y. Y., Yahya, N., & Ibrahim, N. (2007). Extraction, purification and characterization of durian (Durio zibethinus) seed gum. Food Hydrocolloids, 21(2), 273-279. doi:
Baytop, T. (1999). Türkiye'de bitkiler ile tedavi: geçmişte ve bugün: Nobel Tıp Kitabevleri.
Bendahou, A., Dufresne, A., Kaddami, H., & Habibi, Y. (2007). Isolation and structural characterization of hemicelluloses from palm of Phoenix dactylifera L. Carbohydrate Polymers, 68(3), 601-608. doi:
Bostan, A., Razavi, S. M. A., & Farhoosh, R. (2010). Optimization of hydrocolloid extraction from wild sage seed (Salvia macrosiphon) using response surface. International Journal of Food Properties, 13(6), 1380-1392. doi:
Brummer, Y., Cui, W., & Wang, Q. (2003). Extraction, purification and physicochemical characterization of fenugreek gum. Food Hydrocolloids, 17(3), 229-236. doi:
Cui, W., Mazza, G., Oomah, B., & Biliaderis, C. (1994). Optimization of an aqueous extraction process for flaxseed gum by response surface methodology. LWT-Food Science and Technology, 27(4), 363-369. doi:
Dickinson, E. (2003). Hydrocolloids at interfaces and the influence on the properties of dispersed systems. Food Hydrocolloids, 17(1), 25-39. doi:
Estévez, A. M., Saenz, C., Hurtado, M. L., Escobar, B., Espinoza, S., & Suárez, C. (2004). Extraction methods and some physical properties of mesquite (Prosopis chilensis (Mol) Stuntz) seed gum. Journal of the Science of Food and Agriculture, 84(12), 1487-1492. doi:
Garcia‐Ochoa, F., & Casas, J. (1992). Viscosity of locust bean (Ceratonia siliqua) gum solutions. Journal of the Science of Food and Agriculture, 59(1), 97-100. doi:
Ghobadi, E., Varidi, M., Varidi, M., & Koocheki, A. (2018). Fenugreek seed gum: extraction optimization and evaluation of antioxidant properties. Innovative Food Technologies, 5(3), 447-468. doi: (in Persian)
Guil-Guerrero, J., Rebolloso-Fuentes, M., & Isasa, M. T. (2003). Fatty acids and carotenoids from Stinging Nettle (Urtica dioica L.). Journal of Food Composition and Analysis, 16(2), 111-119. doi:
Jouki, M., Mortazavi, S. A., Yazdi, F. T., & Koocheki, A. (2014). Optimization of extraction, antioxidant activity and functional properties of quince seed mucilage by RSM. International journal of biological macromolecules, 66, 113-124. doi:
Kaban, G., Aksu, M., & Kaya, M. (2008). Effect of urtica dioica L. on the growth of staphylococcus aureus in traditional dry fermented sausage (“sucuk”). Journal of Muscle Foods, 19(4), 399-409. doi:
Karazhiyan, H., Razavi, S. M. A., & Phillips, G. O. (2011). Extraction optimization of a hydrocolloid extract from cress seed (Lepidium sativum) using response surface methodology. Food Hydrocolloids, 25(5), 915-920. doi:
Koocheki, A., Mortazavi, S. A., Shahidi, F., Razavi, S. M. A., Kadkhodaee, R., & Milani, J. M. (2010). Optimization of mucilage extraction from Qodume shirazi seed (Alyssum homolocarpum) using response surface methodology. Journal of Food Process Engineering, 33(5), 861-882. doi:
Koocheki, A., Mortazavi, S. A., Shahidi, F., Razavi, S. M. A., & Taherian, A. (2009b). Rheological properties of mucilage extracted from Alyssum homolocarpum seed as a new source of thickening agent. Journal of food engineering, 91(3), 490-496. doi:
Koocheki, A., Taherian, A. R., Razavi, S. M. A., & Bostan, A. (2009a). Response surface methodology for optimization of extraction yield, viscosity, hue and emulsion stability of mucilage extracted from Lepidium perfoliatum seeds. Food Hydrocolloids, 23(8), 2369-2379. doi:
Mohammadi Moghaddam, T., Razavi, S. M. A., & Niknia, S. (2008, September). Physical properties of Balangu and Cress seeds. Paper presented at the Fifth National Congress on Agricultural Machinery and Mechanization, Iranian Association of Agricultural Machinery and Mechanization Engineering, Ferdowsi University of Mashhad, Mashhad, Iran, (in Persian)
Mohsenin, N. (1978). Physical proprieties of plant and animal materials. New York.
Myers, R. H., Montgomery, D. C., & Anderson-Cook, C. M. (2016). Response surface methodology: process and product optimization using designed experiments: John Wiley & Sons.
Razavi, S. M. A., Bostan, A., Niknia, S., & Razmkhah, S. (2011). Functional properties of hydrocolloid extracted from selected domestic Iranian seeds. Journal of Food Research, 21(3), 379-389. (in Persian)
Razavi, S. M. A., Mohammadi Moghaddam, T., & Mohammad Amini, A. (2008). Physical-mechanical properties and chemical composition of Balangu (Lallemantia royleana (Benth. in Walla.)) seed. International Journal of Food Engineering, 4(5). doi:
Razavi, S. M. A., Zahedi, I., & Mahdavian Mehr, H. (2009a). Some engineering properties of Plantago major L.(Barhang) seed. Iranian Food Science & Technology Research Journal, 5(2), 88-96.
Razavi, S. M. A., Bostan, A., & Rahbari, R. (2010a). Computer image analysis and physico-mechanical properties of wild sage seed (Salvia macrosiphon). International Journal of Food Properties, 13(2), 308-316. doi:
Razavi, S. M. A., Bostan, A., & Rezaie, M. (2010b). Image processing and physico‐mechanical properties of basil seed (Ocimum basilicum). Journal of Food Process Engineering, 33(1), 51-64. doi:
Razavi, S. M. A., & Fathi, M. (2009). Moisture-dependent physical properties of grape (Vitis vinifera L.) seed. Philippine Agricultural Scientist, 92(2), 201-212.
Razavi, S. M. A., Mortazavi, S. A., Matia‐Merino, L., Hosseini‐Parvar, S. H., Motamedzadegan, A., & Khanipour, E. (2009b). Optimisation study of gum extraction from Basil seeds (Ocimum basilicum L.). International journal of food Science & Technology, 44(9), 1755-1762. doi:
Razavi, S. M. A., Taheri, H., & Quinchia, L. A. (2011). Steady shear flow properties of wild sage (Salvia macrosiphon) seed gum as a function of concentration and temperature. Food Hydrocolloids, 25(3), 451-458. doi:
Razavi, S. M. A., & Akbari, R. (2012). Biophysical properties of agricultural and food materials: Published by Ferodowsi University of Mashhad, Iran (in Persian)
Sepúlveda, E., Sáenz, C., Aliaga, E., & Aceituno, C. (2007). Extraction and characterization of mucilage in Opuntia spp. Journal of arid environments, 68(4), 534-545. doi:
Singthong, J., Ningsanond, S., & Cui, S. W. (2009). Extraction and physicochemical characterisation of polysaccharide gum from Yanang (Tiliacora triandra) leaves. Food Chemistry, 114(4), 1301-1307. doi:
Wu, Y., Cui, S. W., Tang, J., & Gu, X. (2007). Optimization of extraction process of crude polysaccharides from boat-fruited sterculia seeds by response surface methodology. Food chemistry, 105(4), 1599-1605. doi:
Ye, C.-L., & Jiang, C.-J. (2011). Optimization of extraction process of crude polysaccharides from Plantago asiatica L. by response surface methodology. Carbohydrate Polymers, 84(1), 495-502. doi:
Yiiksel, K., İlkay, O., Ufuk, K., Berrin, O., Sinem, A., Murat, K., & Senay, K. (2009). Fatty acid profile and antimicrobial effect of theseed oils of Urtica dioica and U. PILULIFERA Turk J Pharm Sci, 6(1), 21-30. 
Volume 9, Issue 2
July 2020
Pages 143-160
  • Receive Date: 06 August 2019
  • Revise Date: 17 December 2019
  • Accept Date: 07 February 2020