ABSTRACT:

Determining the protein isolate’s (PI) chemical makeup, amino acid profile, FTIR, and functional characteristics was the aim of this investigation. Protein, fat, fiber, ash, carbs, and moisture are all present in large amounts in QPI (94.25, 2.43, 0.0, 1.83, 1.56, and 5.92%, respectively).
In this work, we used the techniques of alkaline solubilization and acid precipitation to extract proteins from white quinoa with the goal of understanding how the extraction pH (11) affected the quinoa protein isolate’s (QPI) recoverability, purity, and rate of recovery. According to the results, protein purity was 81%, protein extractability was 56.45%, and recovery was 86%. At pH 7 and 11. At PH 7, the maximum solubility for suspension was 67%. 

REFERENCES :

1) Wu, G. (2015). Nutritional properties of quinoa. Quinoa: Improvement and sustainable production, 193-210.
2) Jacobsen, S.-E. (2003). The Worldwide Potential for Quinoa (Chenopodium quinoaWilld.). Food Rev. Int., 19, 167–177. [CrossRef].
3) 6. Bazile, D.; Jacobsen, S.-E.; Verniau, A. (2016). The Global Expansion of Quinoa: Trends and Limits. Front. Plant Sci., 7, 622. [CrossRef] [PubMed].
4) Navruz-Varli, S. and Sanlier, N. (2016). Nutritional and health benefits of quinoa (Chenopodium quinoa Willd.). J. cereal science, 69: 371-376.
5) Thakur, Rohan and Rashmi Nimbalkar. (2020). Quinoa and Chia Seed: Protein Isolates, Properties, Nutrition and Health Benefits. International Journal of Science and Research (USR), 9: 607-617.
6) Valencia-Chamorro, S. A. (2003). Quinoa In: Caballero B. Encyclopedia of Food Science and Nutrition, 8: 4895-4902.
7) Filho, A. M. M.; Pirozi, M. R.; Borges, J. T. D. S.; Pinheiro Sant’Ana, H. M.; Chaves, J. B. P. and Coimbra, J. S. D. R. (2017). Quinoa: Nutritional, functional, and antinutritional aspects. Critical reviews in food science and nutrition, 57: 1618-1630. 
8) Stikic, R.; Glamoclija, D.; Demin, M.; Vucelic-Radovic, B.; Jovanovic, Z.; Milojkovic-Opsenica, D.; Jacobsen, S.-E.; Milovanovic, M. (2012). Agronomical and nutritional evaluation of quinoa seeds (Chenopodium quinoaWilld.) as an ingredient in bread formulations. J. Cereal Sci., 55, 132–138. [CrossRef].
9) Miranda, M.; Vega-Gálvez, A.; Quispe-Fuentes, I.; Rodriguez, M.J.; Maureira, H.; Martínez, E.A. (2012). Nutritional Aspects of Six Quinoa (Chenopodium quinoaWilld.) Ecotypes from three Geographical Areas of Chile. Chil. J. Agric. Res., 72, 175–181. [CrossRef].
10) Nowak, V.; Du, J.; Charrondière, U.R. (2016). Assessment of the nutritional composition of quinoa (Chenopodium quinoa Willd.). Food Chem., 193, 47–54. [CrossRef].
11) Vega-Gálvez, A.; Miranda, M.; Vergara, J.; Uribe, E.; Puente, L.; Martínez, E.A. (2010). Nutrition facts and functional potential of quinoa (Chenopodium quinoa willd.), an ancient Andean grain: A review. J. Sci. Food Agric., 90, 2541–2547. [CrossRef].
12) Wang, X.; Zhao, R.; Yuan,W. Composition and secondary structure of proteins isolated from six different quinoa varieties from China. J. Cereal Sci. 2020, 95, 103036. [CrossRef].
13) Dakhili, S.; Abdolalizadeh, L.; Hosseini, S.M.; Shojaee-Aliabadi, S.; Mirmoghtadaie, L. Quinoa protein: Composition, structure and functional properties. Food Chem. 2019, 299, 125161. [CrossRef] [PubMed]
14) Burrieza, H.P.; Rizzo, A.J.; Moura Vale, E.; Silveira, V.; Maldonado, S. Shotgun proteomic analysis of quinoa seeds reveals novel lysine-rich seed storage globulins. Food Chem. 2019, 293, 299–306. [CrossRef] [PubMed].
15) Caio, G.; Volta, U.; Sapone, A.; Leffler, D.A.; De Giorgio, R.; Catassi, C.; Fasano, A. Celiac disease: A comprehensive current review. BMC Med. 2019, 17, 142. [CrossRef].
16) Föste, M.; Elgeti, D.; Brunner, A. K.; Jekle, M. and Becker, T. (2015). Isolation of quinoa protein by milling fractionation and solvent extraction. Food and Bioproducts Processing, 96: 20-26.
17) Gorinstein, S.; Lojek, A.;Číž, M.; Pawelzik, E.; Delgado‐Licon, E.; Medina, O. J. and Goshev, I. (2008). Comparison of composition and antioxidant capacity of some cereals and pseudocereals. International Journal of Food Science and Technology, 43: 629-637.
18) Abugoch, L. E.; Romero, N.; Tapia, C. A.; Silva, J. and Rivera, M. (2008). Study of some physicochemical and functional properties of quinoa (Chenopodium quinoa Willd) protein isolates. J. Agricultural and Food chemistry, 56: 4745-4750.
19) A.O.A.C. (2023). Official Methods of Analysis of the Association of Official Analytical Chemists. Published by the A.O.A.C. International 17th Ed. Washington, D.C.
20) Aluko and Yada. (1993). R.E. Aluko, R.Y. Yada Relationship of hydrophobicity and solubility with some functional properties of cowpea (Vigna unguiculata) protein isolate J. Sci. Food Agric., 62 (1993), pp. 331-335.
21) Ruiz, G.A.; Xiao,W.; van Boekel, M.; Minor, M.; Stieger, M. (2016).Effect of extraction pH on heat-induced aggregation, gelation and microstructure of protein isolate from quinoa (Chenopodium quinoaWilld). Food Chem., 209, 203–210. [CrossRef].
22) Bradford, M.M. (1976). A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal. Biochem. 72, 248–254. [CrossRef] [PubMed].
23) Eng Shi Ong, * Charlene Jia Ning Pek, Joseph Choon Wee Tan, and Chen Huei Leo. (2022).
24) Antioxidant and Cytoprotective Effect of Quinoa (Chenopodium quinoa Willd.) with Pressurized Hot Water Extraction (PHWE) Antioxidants (Basel). 2020 Nov; 9(11): 1110. Published online 2020 Nov 11. doi:
10.3390/antiox9111110.PMCID: PMC7697190, PMID: 33187302.
25) Durrum, E. L. (1958). Laboratory aids to diagnosis and therapy (paper chromatography and electrophoresis). Annual Review of Medicine, 9: 451- 460.
26) Moore, S.; Spackman, D. H. and Stein, W. H. (1958). Automatic recording apparatus for use in the chromatography of amino acids. In Federation proceedings, 17: 1107-1115.
27) Muyonga, J.; Cole, C. G. And Duodu, K. (2004). Fourier transform infrared (FTIR) spectroscopic study of acid soluble collagen and gelatin from skins and bones of young and adult nile perch (Lates Niloticus) ‖, Food Chem., 86: 325–332.
28) Shengnan Liu, Yun Xie, Bingyi Li, Siqi Li, Wenhua Yu, Aiqian Ye and Qing Guo. (2023).
29) Structural Properties of Quinoa Protein Isolate: Impact of Neutral to High Alkaline Extraction pH. Foods 2023, 12, 2589. https://doi.org/10.3390/ foods12132589.
30) Gaikwad, K. K.; Pawar, V. S.; Shingote, A. B. and Shinde, E. M. (2021). Studies physico-chemical properties of Quinoa (Chenopodium quinoa willd.) seed. Pharma. Innov, 10: 612-645.
31) Östbring, K.; Tullberg, C.; Burri, S.; Malmqvist, E.; Rayner, M. (2019). Protein Recovery from Rapeseed Press Cake: Varietal and Processing Condition Effects on Yield, Emulsifying Capacity and Antioxidant Activity of the Protein Rich Extract. Foods, 8, 627.
32) Van de Vondel, J.; Lambrecht, M.A.; Delcour, J.A. (2020). Osborne extractability and chromatographic separation of protein from quinoa (Chenopodium quinoaWilld.) wholemeal. LWT, 126, 109321. [CrossRef].
33) Florence, T.M. (1980). Degradation of protein disulphide bonds in dilute alkali. Biochem. J. 189, 507–520. [CrossRef].
34) Wang, H.; Johnson, L.; Wang, T. (2004). Preparation of soy protein concentrate and isolate from extruded-expelled soybean meals. J. Am. Oil Chem. Soc. 81, 713–717.
35) Mäkinen, O.E.; Zannini, E.; Koehler, P.; Arendt, E.K. (2016). Heat-denaturation and aggregation of quinoa (Chenopodium quinoa) globulins as affected by the pH value. Food Chem. 196, 17–24. [CrossRef] [PubMed].
36) Gao, Z.; Shen, P.; Lan, Y.; Cui, L.; Ohm, J.-B.; Chen, B.; Rao, J. (2020). Effect of alkaline extraction pH on structure properties, solubility, and beany flavor of yellow pea protein isolate. Food Res. Int., 131, 109045. [CrossRef] [PubMed].
37) Muik, B., Lendl, B., Molina-Diaz, A., Valcarcel, M., and Ayora-Cañada, M. J. (2007). Two-dimensional correlation spectroscopy and multivariate curve resolution for the study of lipid oxidation in edible oils monitored by FTIR and FT-Raman spectroscopy. Anal. Chim. Acta 593, 54–67. doi: 10.1016/j.aca.2007.04.050.
38) Shotts, M.-L., Plans Pujolras, M., Rossell, C., and Rodriguez-Saona, L. (2018). Authentication of indigenous flours (Quinoa, Amaranth and kañiwa) from the Andean region using a portable ATR-Infrared device in combination with pattern recognition analysis. J. Cereal Sci. 82, 65–72. doi: 10.1016/. j.jcs.2018.04.005.
39) Bock, J. E., Connelly, R. K., and Damodaran, S. (2013). Impact of bran addition on water properties and gluten secondary structure in wheat flour doughs studied by attenuated total reflectance fourier transform infrared spectroscopy. Cereal Chem. J. 90, 377–386. doi: 10.1094/CCHEM-01-13-0008-FI.
40) Sivam, A. S., Sun-Waterhouse, D., Perera, C. O., and Waterhouse, G. I. N. (2013). Application of FT-IR and Raman spectroscopy for the study of biopolymers in breads fortified with fibre and polyphenols. Food Res. Int. 50, 574–585. doi: 10.1016/j.foodres.2011.03.039.
41) Roa-Acosta, D. F., Bravo-Gómez, J. E., García-Parra, M. A., Rodríguez-Herrera, R., and Solanilla-Duque, J. F. (2020). Hyper-protein quinoa flour (Chenopodium quinoa Wild): monitoring and study of structural and rheological properties. LWT 121, 108952. doi: 10.1016/j.lwt.2019.108952.
42) García-Salcedo, Á. J., Torres-Vargas, O. L., and Ariza-Calderón, H. (2018). Physical-chemical characterization of quinoa (Chenopodium quinoa Willd.), amaranth (Amaranthus caudatus L.), and chia (Salvia hispanica L.) flours and seeds. Scielo.Org.Co 67, 215–222. doi: 10.15446/acag. v67n2.63666.
43) Rolandelli, G., Gallardo-Navarro, Y. T., García Pinilla, S., Farroni, A. E., Gutiérrez-López, G. F., Buera, M., et al. (2021). Components interactions and changes at molecular level in maize flour-based blends as affected by the extrusion process. A multi-analytical approach. J. Cereal Sci. 99, 103186. doi: 10.1016/j.jcs.2021.103186.
44) Herrero, A. M., Ruiz-Capillas, C., Pintado, T., Carmona, P., and Jimenez-Colmenero, F. (2017). Infrared spectroscopy used to determine effects of chia and olive oil incorporation strategies on lipid structure of reduced-fat frankfurters. Food Chem. 221, 1333–1339. doi: 10.1016/j.foodchem.2016.11.022.
45) Bet, C. D., de Oliveira, C. S., Colman, T. A. D., Marinho, M. T., Lacerda, L. G., Ramos, A. P., et al. (2018). Organic amaranth starch: a study of its technological properties after heat-moisture treatment. Food Chem. 264, 435–442. doi: 10.1016/j.foodchem.2018.05.021.
46) Abbas Ali, M., Anowarul Islam, M., Othman, N. H., and Noor, A. M. (2017). Effect of heating on oxidation stability and fatty acid composition of microwave roasted groundnut seed oil. J. Food Sci. Technol. 54, 4335–4343. doi: 10.1007/s13197-017-2904-1.
47) Rolandelli, G., García-Navarro, Y. T., García-Pinilla, S., Farroni, A. E., Gutiérrez-López, G. F., Buera, M., et al. (2020). Microstructural characteristics and physical properties of corn-based extrudates affected by the addition of millet, sorghum, quinoa and canary seed flour. Food Struct. 25, 100140. doi: 10.1016/j.foostr.2020.100140.
48) Cueto, M., Farroni, A., Rodríguez, S. D., Schoenlechner, R., Schleining, G., and del Pilar Buera, M. (2018). Assessing changes in enriched maize flour formulations after extrusion by means of FTIR, XRD, and chemometric analysis. Food Bioprocess Technol. 11, 1586–1595. doi: 10.1007/s11947-018-2113-6.