Journal of Applied Science and Engineering

Published by Tamkang University Press


Impact Factor



Nor Shazwani Daud, Nordin Sabli, Hiroyuki Yoshida, and Shamsul IzharThis email address is being protected from spambots. You need JavaScript enabled to view it.

Department of Chemical and Environmental Engineering, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia



Received: August 29, 2023
Accepted: February 4, 2024
Publication Date: April 6, 2024

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||  

The attractive characteristics of subcritical water (SubCW) lie in its ability to extract and hydrolyze bioactive compounds from natural matrices. These properties allow water to act as an efficient solvent with a short extraction time. This paper aims to study the effect of SubCW temperature on wheat germ protein extraction for application in the coagulation of the water treatment process. Concerning coagulation performance, a mass-to-water ratio and extraction time are other factors studied, besides the SubCW temperature. Wheat germ (WG) is an excellent source of plant-based protein that is suitable as a biocoagulant for substituting the widely used chemical coagulants. Experiments were conducted in a batch reactor at a SubCW temperature between 100 and 170C with a solid-to-water ratio (s/w) of 0.5:25–2:25 and an extraction time of 5–30 min. The extracts obtained after the SubCW process contained a distinctive amount of protein, which was then used as a coagulant extract solution in the coagulation process. The highest total protein yield was 22.93 g/100 g-WG, obtained at 160C, which corresponds to protein extraction of 82.8%. The lowest turbidity, 48.9 NTU, was achieved at 120C in SubCW extracts, which resulted in a 98.8% turbidity reduction. From the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), it was observed that proteins with a molecular weight less than 117 kDa exhibit superior coagulation activity. Consequently, wheat germ protein was efficiently extracted by SubCW and can be used as a promising bio-coagulant alternative in waste treatment facilities.


Keywords: Coagulation; Protein; Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Subcritical Water; Wheat Germ

  1. [1] L. Du, P. J. Arauzo, M. F. Meza Zavala, Z. Cao, M. P. Olszewski, and A. Kruse, (2020) “Towards the properties of different biomass-derived proteins via various extraction methods" Molecules 25(3): 488. DOI: 10.3390/molecules25030488.
  2. [2] S. Ibrahim, R. Santos, and S. Bowra, (2018) “Optimization of subcritical water mediated extraction of apple pomace polyphenolics and their antioxidant activity" Journal of Chromatography & Separation Techniques 9(05):
  3. [3] X. Liang, Q. Fan, et al., (2013) “Application of subcritical water extraction in pharmaceutical industry" Journal of Materials Science and Chemical Engineering 1(05): 1.
  4. [4] A. M. Silva, A. S. Luís, M. M. Moreira, R. Ferraz, T. Brezo-Borjan, J. Švarc-Gaji´c, P. C. Costa, C. DelerueMatos, and F. Rodrigues, (2022) “Influence of temperature on the subcritical water extraction of Actinidia arguta leaves: A screening of pro-healthy compounds" Sustainable Chemistry and Pharmacy 25: 100593. DOI: 10.1016/j.scp.2021.100593.
  5. [5] M. Polikovsky, A. Gillis, E. Steinbruch, A. Robin, M. Epstein, A. Kribus, and A. Golberg, (2020) “Biorefinery for the co-production of protein, hydrochar and additional co-products from a green seaweed Ulva sp. with subcritical water hydrolysis" Energy Conversion and Management 225: 113380. DOI: 10.1016/j.enconman.2020.113380.
  6. [6] M. N. Nasrabadi, A. S. Doost, and R. Mezzenga, (2021) “Modification approaches of plant-based proteins to improve their techno-functionality and use in food products" Food Hydrocolloids 118: 106789. DOI: 10.1016/j.foodhyd.2021.106789.
  7. [7] K.-X. Zhu, X.-H. Sun, and H.-M. Zhou, (2009) “Optimization of ultrasound-assisted extraction of defatted wheat germ proteins by reverse micelles" Journal of Cereal Science 50(2): 266–271. DOI: 10.1016/j.jcs.2009.06.006.
  8. [8] C. Ferreira, M. M. Moreira, C. Delerue-Matos, and M. Sarraguça, (2023) “Subcritical Water Extraction to Valorize Grape Biomass—A Step Closer to Circular Economy" Molecules 28(22): 7538. DOI: 10.3390/molecules28227538.
  9. [9] S. Areeya, E. J. Panakkal, M. Sriariyanun, T. Kangsadan, A. Tawai, S. Amornraksa, U. W. Hartley, and P. Yasurin, (2023) “A review on chemical pretreatment of lignocellulosic biomass for the production of bioproducts: mechanisms, challenges and applications" Applied Science and Engineering Progress 16(3): 6767–6767. DOI: 10.14416/j.asep.2023.02.008.
  10. [10] D. Jose, N. Kitiborwornkul, M. Sriariyanun, and K. Keerthi, (2022) “A review on chemical pretreatment methods of lignocellulosic biomass: Recent advances and progress" Applied Science and Engineering Progress 15(4): 6210–6210. DOI: 10.14416/j.asep.2022.08.001.
  11. [11] J. Zhang, C. Wen, H. Zhang, Y. Duan, and H. Ma, (2020) “Recent advances in the extraction of bioactive compounds with subcritical water: A review" Trends in Food Science & Technology 95: 183–195. DOI: 10.1016/j.tifs.2019.11.018.
  12. [12] N. L. Rahmah, S. M. M. Kamal, A. Sulaiman, F. S. Taip, S. I. Siajam, et al., (2022) “Optimization Of Phenolic Compounds And Antioxidant Extraction From Piper Betle Linn. Leaves Using Pressurized Hot Water" Journal of Applied Science and Engineering 26(2): 175– 184. DOI: 10.6180/jase.202302_26(2).0003.
  13. [13] N. H. Zainan, M. A. M. Sapardi, B. C. H. Ho, S. I. Siajam, S. M. M. Kamal, M. K. Danquah, and R. Harun, (2022) “Correction to: Kinetic and thermodynamic characterization of amino acids generation via subcritical water reaction of microalgae Nannochloropsis sp. biomass" Biomass Conversion and Biorefinery: 1–1. DOI: 10.1007/s13399-021-01908-w.
  14. [14] W. Abdelmoez and H. Yoshida, (2013) “Production of amino and organic acids from protein using sub-critical water technology" International Journal of Chemical Reactor Engineering 11(1): 369–384. DOI: 10.1515/ijcre-2013-0017.
  15. [15] H. D. D. Ziero, L. C. Ampese, W. G. Sganzerla, P. C. Torres-Mayanga, M. T. Timko, S. I. Mussatto, and T. Forster-Carneiro, (2022) “Subcritical water hydrolysis of poultry feathers for amino acids production" The Journal of Supercritical Fluids 181: 105492. DOI: 10.1016/j.supflu.2021.105492.
  16. [16] Y. Cheng, F. Xue, S. Yu, S. Du, and Y. Yang, (2021) “Subcritical water extraction of natural products" Molecules 26(13): 4004.
  17. [17] F. He, (2011) “Bradford protein assay" Bio-protocol: e45–e45.
  18. [18] M.-J. Ko, M.-R. Kwon, and M.-S. Chung, (2020) “Pilotscale subcritical-water extraction of nodakenin and decursin from Angelica gigas Nakai" Food Science and Biotechnology 29: 631–639.
  19. [19] A. A. Suleiman, U. A. Abdullahi, A. Suleiman, S. A. Suleiman, and H. U. Abubakar, (2022) “Correlation and regression model for physicochemical quality of groundwater in the Jaen District of Kano State, Nigeria" Journal of Statistical Modeling & Analytics (JOSMA) 4(1):
  20. [20] V. V. Acharya and P. Chaudhuri, (2021) “Modalities of protein denaturation and nature of denaturants" International Journal of Pharmaceutical Sciences Review and Research 69(2): 19–24.
  21. [21] G. Náthia-Neves and E. Alonso, (2024) “Optimization of the subcritical water treatment from sunflower by-product for producing protein and sugar extracts" Biomass Conversion and Biorefinery 14(2): 1637–1650.
  22. [22] A. H. Asl and M. Khajenoori, (2013) “Subcritical water extraction" Mass Transfer-Advances in sustainable energy and environment oriented numerical modeling: 459–487.
  23. [23] B. Díaz-Reinoso, S. Rivas, J. Rivas, and H. Domínguez, (2023) “Subcritical water extraction of essential oils and plant oils" Sustainable Chemistry and Pharmacy 36: 101332.
  24. [24] S. Joki´c, T. Gagi´c, Ž. Knez, D. Šubari´c, and M. Škerget, (2018) “Separation of active compounds from food by-product (cocoa shell) using subcritical water extraction" Molecules 23(6): 1408. DOI: 10.3390/molecules23061408.
  25. [25] T. Okuda, A. U. Baes, W. Nishijima, and M. Okada, (2001) “Coagulation mechanism of salt solution-extracted active component in Moringa oleifera seeds" Water research 35(3): 830–834. DOI: 10.1016/S0043-1354(00)00296-7.
  26. [26] V. V. Acharya and P. Chaudhuri, (2021) “Modalities of protein denaturation and nature of denaturants" International Journal of Pharmaceutical Sciences Review and Research 69(2): 19–24.
  27. [27] S. Awaluddin, S. Thiruvenkadam, S. Izhar, Y. Hiroyuki, M. K. Danquah, R. Harun, et al., (2016) “Subcritical water technology for enhanced extraction of biochemical compounds from Chlorella vulgaris" BioMed research international 2016: DOI: 10.1155/2016/5816974.
  28. [28] J. Lu, X. Feng, Y. Han, and C. Xue, (2014) “Optimization of subcritical fluid extraction of carotenoids and chlorophyll a from Laminaria japonica Aresch by response surface methodology" Journal of the Science of Food and Agriculture 94(1): 139–145. DOI: 10.1002/jsfa.6224.
  29. [29] M. Choudhary and S. Neogi, (2017) “A natural coagulant protein from Moringa oleifera: isolation, characterization, and potential use for water treatment" Materials Research Express 4(10): 105502. DOI: 10.1088/2053-1591/aa8b8c.
  30. [30] A. N. Jones and J. Bridgeman, (2019) “Identifying Molecular Mass of Coagulant Protein from Edible Hibiscus Seeds Using SDS-PAGE Analysis" Journal of Environmental Engineering 145(11): 04019077. DOI: 10.1061/(ASCE)EE.1943-7870.0001595.
  31. [31] N. A. Awang and H. A. Aziz, (2012) “Hibiscus rosasinensis leaf extract as coagulant aid in leachate treatment" Applied Water Science 2: 293–298. DOI: 10.1007/s13201-012-0049-y.
  32. [32] Z. Zhang, S. Xia, J. Zhao, and J. Zhang, (2010) “Characterization and flocculation mechanism of high-efficiency microbial flocculant TJ-F1 from Proteus mirabilis" Colloids and Surfaces B: Biointerfaces 75(1): 247–251. DOI: 10.1016/j.colsurfb.2009.08.038.
  33. [33] A. F. Santos, L. A. Luz, A. C. Argolo, J. A. Teixeira, P. M. Paiva, and L. C. Coelho, (2009) “Isolation of a seed coagulant Moringa oleifera lectin" Process biochemistry 44(4): 504–508. DOI: 10.1016/j.procbio.2009.01.002.



60th percentile
Powered by  Scopus

SCImago Journal & Country Rank

Enter your name and email below to receive latest published articles in Journal of Applied Science and Engineering.