Isolation of protein isolated from defatted Carica papaya linn. seeds: influence of pH and NaCl on its solubility and functional properties

Oseni Kadiri, Charles T. Akanbi, Saka O. Gbadamosi


This work reports the isolation of protein from defatted Carica papaya Linn. Seed (CPS), with the crude protein product containing 88.08% protein. Under its natural conditions, the solubility of this protein isolate is comparable to sweet lupin protein isolate (98.79%). The solubility of the protein decreases with decreasing pH, with the minimum solubility observed at its isoelectric point (pH 4). The water holding capacity, oil holding capacity, foaming capacity, foam stability, emulsifying capacity and emulsion stability were found to be 3.65 g/g, 3.60 g/g, 26.14%, 13.06%, 74.05m2/g, 100.80%. The profiles of functional properties were determined with varying pH values and NaCl concentration, and improved properties were observed in the alkaline pH range and in the presence of NaCl.


Carica papaya seed; functional properties; foaming properties; Protein isolate; proximate composition.

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Aluko RE & Yada RY (1993). Relationship of hydrophobicity and solubility with some functional properties of cowpea (Vigna unguiculata) protein isolate. Journal of the Science of Food and Agriculture, 62(4), 331-335.

Aluko RE, McIntosh T, & Katepa‐Mupondwa F (2005). Comparative study of the polypeptide profiles and functional properties of Sinapis alba and Brassica juncea seed meals and protein concentrates. Journal of the Science of Food and Agriculture, 85(11), 1931-1937.

AOAC (Association of Official Analytical Chemists). (2005). Official methods of analysis of the Association of Analytical Chemists International.

Aremu MO, Olaofe O, & Akintayo ET (2007). Functional properties of some Nigerian varieties of legume seed flours and flour concentration effect on foaming and gelation properties. Journal of Food Technology, 5 (2), 109-115.

Cepeda E, Villaran MC, & Aranguiz N (1998). Functional properties of faba bean (Vicia faba) protein flour dried by spray drying and freeze drying. Journal of Food Engineering, 36(3), 303-310.

Chavan UD, McKenzie DB, & Shahidi F (2001). Functional properties of protein isolates from beach pea (Lathyrus maritimus L.). Food chemistry, 74(2), 177-187.

Damodaran S. Food proteins: An overview. In S. Damodaran and A. Paraf (Eds.), Food proteins and their applications (1997). New York: Marcel Dekker.pp 1-21.

Deng Q, Wang L, Wei F, Xie B, Huang F, Huang W, & Xue S (2011). Functional properties of protein isolates, globulin and albumin extracted from Ginkgo biloba seeds. Food Chemistry, 124(4), 1458-1465.

Eltayeb ARSM, Ali AO, Abou-Arab AA, & Abu-Salem FM (2011). Chemical composition and functional properties of flour and protein isolate extracted from Bambara groundnut (Vigna subterranean). African Journal of Food Science, 5(2), 82-90.

Food and Agricultural Organisation (FAO), United Nations statistics (2007), online Website

Gbadamosi SO, Abiose SH, & Aluko RE (2012). Amino acid profile, protein digestibility, thermal and functional properties of Conophor nut (Tetracarpidium conophorum) defatted flour, protein concentrate and isolates. International journal of food science & technology, 47(4), 731-739.

Idouraine A, Yensen SB, & Weber CW (1991). Tepary bean flour, albumin and globulin fractions functional properties compared with soy protein isolate. Journal of Food Science, 56(5), 1316-1318.

Kadiri O & Olawoye B (2016). Vernonia amygdalina: An underutilized vegetable with nutraceutical Potentials–A Review. Turkish Journal of Agriculture-Food Science and Technology, 4(9), 763-768.

Kadiri O, Gbadamosi SO, Olawoye B & Akanbi CT (2016). Changes in total phenolic and protein contents during production of protein isolates from Carioca papaya (pawpaw) seeds. Turkish Journal of Agriculture-Food Science and Technology, 4(11), 1006-13.

Kain RJ, Chen Z, Sonda TS, & Abu-Kpawoh JC (2009). Study on the effects of enzymatic hydrolysis on the physical, functional and chemical properties of peanut protein isolates extracted from defatted heat pressed peanut meal flour (Arachis hypogaea L.). Pakistan Journal of Nutrition, 8(6), 818-825.

Kanu PJ, Kerui Z, Ming ZH, Haifeng Q, Kanu JB, & Kexue Z (2007). Sesame protein 11: Functional properties of sesame (Sesamum indicum L.) protein isolate as influenced by pH, temperature, time and ratio of flour to water during its production. Asian Journal of Biochemistry, 2(5), 289-301.

Kaur M & Singh N (2007). Relationships between various functional, thermal and pasting properties of flours from different Indian black gram (Phaseolus mungo L.) cultivars. Journal of the Science of Food and Agriculture, 87(6), 974-984.

Kinsella JE (1979). Functional properties of soy proteins. Journal of the American Oil Chemists' Society, 56(3Part1), 242-258.

Lawal OS, Adebowale KO, Ogunsanwo BM, Sosanwo OA, & Bankole SA (2005). On the functional properties of globulin and albumin protein fractions and flours of African locust bean (Parkia biglobossa). Food chemistry, 92(4), 681-691.

L'hocine L, Boye JI, & Arcand Y (2006). Composition and functional properties of soy protein isolates prepared using alternative defatting and extraction procedures. Journal of food science, 71(3), C137-C145.

Lowry OH, Rosebrough NJ, Farr AL, & Randall RJ (1951). Protein measurement with the Folin phenol reagent. Journal of biological chemistry, 193, 265-275.

Makri EA & Doxastakis GI (2006). Emulsifying and foaming properties of Phaseolus vulgaris and coccineus proteins. Food chemistry, 98(3), 558-568. McClements DJ (2003). Analysis of food products. Food science, 581, 1-57.

Hojilla-Evangelista M P, Evangelista R L, & Wu Y V (2009). Characterization of milkweed (Asclepias spp.) seed proteins. Industrial crops and products, 29(2-3), 275-280. Myers C (1988). Functional attributes of protein isolates. In Characterization of proteins (pp. 491-549). Humana Press.

Ogundele JO, Oshodi AA, Sanni T A, & Amoo I A (2013). Protein isolates of gourd melon seeds and their functional properties. Am. J. Food. Nutr, 3(4), 176-181.

Ogungbenle HN, Oshodi AA, & Oladimeji MO (2009). The proximate and effect of salt applications on some functional properties of quinoa (Chenopodium quinoa) flour. Pakistan J Nutr, 8(1), 49-52.

Ogunwolu SO, Henshaw FO, Mock HP, Santros A, & Awonorin SO (2009). Functional properties of protein concentrates and isolates produced from cashew (Anacardium occidentale L.) nut. Food chemistry, 115(3), 852-858.

Osman NM, Amro BH, Mohamed‐Ahmed IA, & Babiker EE (2005). Effect of autoclaving on solubility and functional properties of chickpea (Cicer arietinum) flour as a function of salt concentration. Journal of Food Technology, 3(3), 336-341.

Peleg M & Bagley EB (1983). Physical properties of foods. In IFT basic symposium series (USA). AVI Pub. Co.

Ragab DM, Babiker EE, & Eltinay AH (2004). Fractionation, solubility and functional properties of cowpea (Vigna unguiculata) proteins as affected by pH and/or salt concentration. Food chemistry, 84(2), 207-212.

Sadeghi MA & Bhagya S (2009). Effect of recovery method on different property of mustard protein. World Journal of Dairy & Food Sciences, 4(2), 100-106.

Sathe SK & Salunkhe DK (1981). Isolation, partial characterization and modification of the great northern bean (Phaseolus vulgaris L.) starch. Journal of Food Science, 46(2), 617-621.

Saunders RM, Connor MA, Booth AN, Bickoff EM, & Kohler GO (1973). Measurement of digestibility of alfalfa protein concentrates by in vivo and in vitro methods. The Journal of nutrition, 103(4), 530-535.

Suliman MA, El Tinay AH, Elkhalifa AEO, Babiker EE, & Elkhalil EA (2006). Solubility as influenced by pH and NaCl concentration and functional properties of lentil proteins isolate. Pakistan Journal of Nutrition, 5(6), 589-593.

Sze-Tao KWC & Sathe SK (2000). Functional properties and in vitro digestibility of almond (Prunus dulcis L.) protein isolate. Food chemistry, 69(2), 153-160.

Ulloa JA, Rosas‐Ulloa P, & Ulloa‐Rangel BE (2011). Physicochemical and functional properties of a protein isolate produced from safflower (Carthamus tinctorius L.) meal by ultrafiltration. Journal of the Science of Food and Agriculture, 91(3), 572-577.

Wanasundara PKJPD & Shahidi F (1997). Functional properties of acylated flax protein isolates. Journal of Agricultural and Food Chemistry, 45(7), 2431-2441.

Wang JC & Kinsella JE (1976). Functional properties of novel proteins: Alfalfa leaf protein. Journal of food science, 41(2), 286-292.

Yuliana M, Truong CT, Huynh LH, Ho QP, & Ju YH (2014). Isolation and characterization of protein isolated from defatted cashew nut shell: influence of pH and NaCl on solubility and functional properties. LWT-Food Science and Technology, 55(2), 621-626.


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