Investigation of functional properties of protein co-precipitates extracted from pomegranate and grape seeds

Document Type : Research Article


1 Associate Professor, Department of Food science and technology, Gorgan University of Agricultural Sciences and Natural Resources, Golestan , Iran

2 Ph. D. Student, Department of Food science and technology, Gorgan university of Agricultural Sciences and Natural Resources, Golestan, Iran.


The protein co-precipitate is an economical method to produce high-protein foods with appropriate functional properties.Grape and pomegranate seeds are useful sources of protein as food waste. The efficient utilization of waste to produce high-value food products reduces the costs waste disposal in the food industry. In this study,the functional properties of grape and pomegranate seeds protein co-precipitated were investigated at 40, 55 and 75% ammonium sulfate. Finally, 55% saturation of ammonium sulfate was selected according to the results of electrophoresis. The functional properties of produced proteins including emulsion activity, emulsion stability, oil and water holding capacity, solubility and viscosity of the samples were investigated. The results showed that the highest solubility of supernatant protein and pellet protein was obtained at pH = 6 and pH = 12, and the emulsion activity of supernatant and pellet were 4.95- 13.37 m2/g and 8.84-16.83 m2/g, respectively.Also, the emulsion stability of the supernatant proteins was 15.60- 23.59 min, and the emulsion stability of the pellet grape-pomegranate co-precipitated proteins was 17.74- 39.91 min. The results showed that the proteins in the pellet had higher water holding capacity (1.68 g) than the supernatant proteins (0.24 g) (p

Graphical Abstract

Investigation of functional properties of protein co-precipitates extracted from pomegranate and grape seeds


  • The protein co-precipitate is an economical method to produce high-protein foods with appropriate functional properties.
  • Grape and pomegranate seeds are useful sources of protein as food waste.
  • The grape-pomegranate seed proteins could be precipitated and separated into supernatants and pellets by using phosphate buffer (pH = 7) and ammonium sulfate salt (55%) .


Main Subjects

[1] Alu’datt, M. H., Al-Rabadi, G. J., Alli, I., Ereifej, K., Rababah, T., Alhamad, M. N., & Torley, P. J. (2013). Protein co-precipitates: A review of their preparation and functional properties. Food Bioprod. Process., 91, 327-335.
[2] Yu, J., Ahmedna, M., & Goktepe, I. (2007). Peanut protein concentrate: Production and functional properties as affected by processing. Food Chem., 103, 121-129.
[3] Alu’datt, M. H., Alli, I., & Nagadi, M. (2012). Preparation, characterization and properties of whey-soy proteins co-precipitates. Food Chem., 134, 294-300.
[4]Youssef, A. M., Abu‐Foul, N. S., & Moharram, Y. G. (1995). Preparation and characteristics of  coprecipitate proteins from oilseeds and legumes seeds. Food/Nahrung., 39, 475-482.
[5] Martínez, R., Torres, P., Meneses, M. A., Figueroa, J. G., Pérez-Álvarez, J. A., & Viuda-Martos, M. (2012). Chemical, technological and in vitro antioxidant properties of mango, guava, pineapple and passion fruit dietary fibre concentrate. Food Chem., 135, 1520-1526.
[6] Mahfoudhi, N., Ksouri, R., & Hamdi, S. (2016). Nanoemulsions as potential delivery systems for bioactive compounds in food systems: Preparation, characterization, and applications in food industry. In: Mihai Grumezescu. A (Eds.). Emulsions (pp. 365-403) Academic Press.
[7] Samadloui, H.R., Azizi, M.H., & Barzegar, M. (2006). Investigation of Physicochemical Properties of Ten Varieties of Yazd Pomegranate Seed. IJFST., 3, 19-26. [In Persian]
[8] Aviram, M., Dornfeld, L., Rosenblat, M., Volkova, N., Kaplan, M., Coleman, R., Hayek, T., Presser, D.,  & Fuhrman, B. (2000). Pomegranate juice consumption reduces oxidative stress, atherogenic modifications to LDL, and platelet aggregation: studies in humans and in atherosclerotic apolipoprotein E–deficient mice. AM J CLIN NUTR., 71, 1062-1076.
[9] Yang, H., Li, M., Qi, X., Lv, C., Deng, J., & Zhao, G. (2012). Identification of seven water-soluble non-storage proteins from pomegranate (Punica granatum Linn.) seeds. Food Sci. Technol. Int., 18, 329-338.
[10] Costa, G.N., Tonon, R. V., Mellinger‐Silva, C., Galdeano, M.C., Iacomini, M., Santiago, M.C., Almeida, E.L., & Freitas, S.P. (2019). Grape seed pomace as a valuable source of antioxidant fibers. J. Sci. Food Agric., 99, 4593-4601.
[11] Sogi, D.S., Arora, M.S., Garg, S. K., & Bawa, A.S. (2002). Fractionation and electrophoresis of tomato waste seed proteins. Food Chem., 76, 449-454.
[12] AOCS. (2007). Official methods and recommended practices of the American oil chemist's Society.
 [13] Miller, M. K., Schonhorst, M. H., & McDaniel, R. G. (1972). Identification of Hybrids from Alfalfa Crosses by Electrophoresis of Single Seed Proteins 1. Crop Sci., 12, 535-537.
[14] Nooralabettu, K. P. (2014). Optimisation of ammonium sulfate precipitation method to achieve high throughput concentration of crude alkaline phosphatase from Brown shrimp (Metapenaeus monoceros) hepatopancreas. Int J Anal Bio-Sci., 2, 7-16.
[15] Laemmli, U. K. (1970). Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature., 227(5259), 680-685.
[16] Were, L., Hettiarachchy, N. S., & Kalapathy, U. (1997). Modified soy proteins with improved foaming and water hydration properties. J. Food Sci., 62, 821-824.
[17] Pearce, K. N., & Kinsella, J. E. (1978). Emulsifying properties of proteins: evaluation of a turbidimetric technique. J. Agric. Food Chem., 26, 716-723.
[18]  Beuchat, L. R. (1977). Functional and electrophoretic characteristics of succinylated peanut flour protein. J. Agric. Food Chem., 25, 258-261.
[19] Mohamed, I. S., Osman, A., Wahdan, K. M., & Sitohy, M. Z. (2019). Chemical Evaluation and Functional Properties of Luffa Seeds Protein. ZJAR., 46, 467-474.
[20] Horax, R., Hettiarachchy, N., Kannan, A., & Chen, P. (2011). Protein extraction optimisation, characterisation, and functionalities of protein isolate from bitter melon (Momordica charantia) seed. Food Chem., 124, 545-550.
[21] Boye, J. I., Aksay, S., Roufik, S., Ribéreau, S., Mondor, M., Farnworth, E., & Rajamohamed, S. H. (2010). Comparison of the functional properties of pea, chickpea and lentil protein concentrates processed using ultrafiltration and isoelectric precipitation techniques. Food Res. Int., 43, 537-546.
[22] Kumar, K. S., Ganesan, K., Selvaraj, K., & Rao, P. S. (2014). Studies on the functional properties of protein concentrate of Kappaphycus alvarezii (Doty) Doty–An edible seaweed. Food chem., 153, 353-360.
[23] Adebiyi, A. P., & Aluko, R. E. (2011). Functional properties of protein fractions obtained from commercial yellow field pea (Pisum sativum L.) seed protein isolate. Food Chem., 128, 902-908.
[24] Jain, A., Prakash, M., & Radha, C. (2015). Extraction and evaluation of functional properties of groundnut protein concentrate. J. Food Sci. Technol., 52, 6655-6662.
[25] Shevkani, K., Kaur, A., Kumar, S., & Singh, N. (2015). Cowpea protein isolates: functional properties and application in gluten-free rice muffins. LWT--Food Sci. Technol., 63(2), 927-933.
[26] Keshavarz Hedayati, A.A., Alami, M., Motamedzadegan, A., Maghsoodlou, Y., & Ghorbani, M. (2014). Functional Properties of Iranian Rice Bran Protein Concentrates. EJFPP., 6, 17-33. [In Persian]
[27] Güzel, M., Çelik, M., & Yildirim, M. (2019). Effect of pH on Protein Extraction from Mahaleb Kernels and Functional Properties of Resulting Protein Concentrate. Int. J. Food Eng., 15, 3023-3032.
[28] Wu, H., Wang, Q., Ma, T., & Ren, J. (2009). Comparative studies on the functional properties of various protein concentrate preparations of peanut protein. Food Res. Int., 42, 343-348.
[29] Seena, S., & Sridhar, K. R. (2005). Physicochemical, functional and cooking properties of under explored legumes, Canavalia of the southwest coast of India. Food Res. Int., 38, 803-814.
[30] Chandi, G. K., & Sogi, D. S. (2007). Functional properties of rice bran protein concentrates. J. Food Eng., 79, 592-597.
[31] Ogunwolu, S. O., Henshaw, F. O., Mock, H. P., Santros, A., & Awonorin, S. O. (2009). Functional properties of protein concentrates and isolates produced from cashew (Anacardium occidentale L.) nut. Food Chem., 115, 852-858.
[32] Fernández-Quintela, A., Macarulla, M. T., Del Barrio, A. S., & Martínez, J. A. (1997). Composition and functional properties of protein isolates obtained from commercial legumes grown in northern Spain. Plant Foods Hum. Nutr., 51, 331-341.