Ionic liquid ultrasound-assisted extraction (IL-UAE) for duck feather keratin and in silico evaluation as a potential procollagen n-endopeptidase inhibitor
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Abstract
This research aims to optimize keratin extraction from duck feathers using an eco-friendly ionic liquid-ultrasound-assisted extraction (IL-UAE) method and evaluate its potential applications in tissue engineering. It investigated the effects of deposition pH (1-6), ultrasonication temperature (40-60°C), and time (60-180 min) on extraction yield and physicochemical properties. The results demonstrated the optimal extraction conditions at pH 3, 40°C, and 60 minutes, yielding 82% keratin with a 0.50 mg/mL concentration, while the lowest yield production was found at pH 6 (33%, 0.20 mg/mL). Meanwhile, characterization via FTIR confirmed predominant ?-sheet structures with characteristic peaks at 3250-3300 cm?¹ (N-H/O-H stretching) and 1700-1500 cm?¹ (C=O stretching). SDS-PAGE revealed pure keratin bands (10-15 kDa), while SEM showed layered, porous morphology suitable for biomaterial applications. Thermogravimetric analysis, furthermore, identified three degradation stages occurred at 0-200°C (3.05% loss), 200-400°C (39.37% loss), and 400-700°C (31.13% loss). Amino acid profiling revealed high L-cystine content (153,064.90-156,926.33 mg/kg) with the significant amounts of glycine (63,958.25-64,064.73 mg/kg), L-proline (77,631.16-77,717.42 mg/kg), and L-leucine (59,111.43-59,198.60 mg/kg). In silico molecular docking studies identified leucine as a promising procollagen N-endopeptidase inhibitor (binding energy -5.0 kcal/mol), which controlled the collagen-breaking and forming process. This ability makes keratin potential to be developed as a scaffold for bone tissue regeneration in medical industry.
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Sianita, M. M., Kusumawati, N., Asri, M. T., Dzulkarnain, S. A., Al Hafidl, A. N., Kahfi, A., Nabila, M. A., Setiawan, F., Isyrak, L., & Rahmawati, K. (2025). Ionic liquid ultrasound-assisted extraction (IL-UAE) for duck feather keratin and in silico evaluation as a potential procollagen n-endopeptidase inhibitor. Communications in Science and Technology, 10(1), 75-86. https://doi.org/10.21924/cst.10.1.2025.1669
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References
C. Sing, T. Lin, S. Bartholomew, J.S. Bell, C. Bennett, K. Beyene, et al., Global Epidemiology of Hip Fractures: Secular Trends in Incidence Rate, Post-Fracture Treatment, and All-Cause Mortality, J. Bone Miner. Res. 38(8) (2023) 1064-1075.
Y. Rong, X. Liang, K. Jiang, H. Jia, H. Li, B. Lu, et al., Global Trendsin Research of Programmed Cell Deathin Osteoporosis: A bibliometric and Visualized Analysis (2000–2023), Orthop. Surg. 16 (2024) 1783-1800.
M.A. Clynes, N.C. Harvey, E.M. Curtis, N.R. Fuggle, E.M. Dennison, C. Cooper, The epidemiology of osteoporosis, Br. Med. Bull. 133(1) (2020) 105-117.
M.A. Clynes, L.D. Westbury, E.M. Dennison, J.A. Kanis, MK. Javaid, N.C. Harvey, et al., Bone densitometry worldwide: a global survey by the ISCD and IOF, Osteoporos. Int. 31 (2020) 1779-1786.
M. Zhang, R. Lin, X. Wang, J. Xue, C. Deng, C. Feng, et al., 3D printing of Haversian bone–mimicking scaffolds for multicellular delivery in bone regeneration, Sci. Adv. 6(12) (2020) eaaz6725.
H. Shanshan, K. Nie, J. Li, Q. Sun, X. Wang, X. Li, et al., 3D Electrospun Nanofiber-Based Scaffolds: From Preparation and Properties to Tissue Regeneration Applications, Stem Cells Int. 22 (2021) 8790143.
A.R. Khan, N. S. Grewal, Z. Jun, F.M.O. Tawfiq, F. Tchier, R.M. Zulqarnain, et al., Raising the Bar: Progress in 3D-Printed Hybrid Bone Scaffolds for Clinical Applications: A Review, Sage J. 33 (2024) 1-17.
M. Krishani, W.Y. Shin, H. Suhaimi, N.S. Sambudi, Development of Scaffolds from Bio-Based Natural Materials for Tissue Regeneration Applications: A Review, Gels 9 (2022) 100.
Y. Kim, S. Vijayavenkataraman, G. Cidonio, Biomaterials and scaffolds for tissue engineering and regenerative medicine, BMC Methods 1(2) (2024).
M.S.B. Reddy, D. Ponnamma, R. Choudhary, K.K. Sadasivuni, A Comparative Review of Natural and Synthetic Biopolymer Composite Scaffolds, Polymers 13 (2021) 1105.
A.E. Eldeeb, S. Salah, N.A. Elkasabgy, Biomaterials for Tissue Engineering Applications and Current Updates in the Field: A Comprehensive Review, AAPS PharmSciTech. 23 (2022) 267.
L.E. Rojas-Martíneza, C.G. Flores-Hernandeza, L.M. López-Marínb, A.L. Martinez-Hernandeza, S.B. Thoratc, C.D. Reyes Vasquez, et al., 3D printing of PLA composites scaffolds reinforced with keratin and chitosan: Effect of geometry and structure, Eur. Polym. J. 141 (2020) 110088.
H. Zhang, F. Su, X. Ma, G. Zhao, Brief introduction of keratin and its biological application, especially in drug delivery, Emerg. Mater. 4 (2021) 1225-1242.
J.E. Plowman, R.E. Miller, A. Thomas, A.J. Grosvenoer, D.P. Harland, S. Deb-Choudhury, Adetailed mapping of the readily accessible disulphide bonds in the cortex of wool fibres, Proteins 89 (2021) 708-720.
M. Konop, A.K. Laskowska, M. Rybka, E. Klodzinska, D. Sulejczak, R.A. Schwartz, Keratin Scaffolds Containing Casomorphin Stimulate Macrophage Infiltration and Accelerate Full-Thickness Cutaneous Wound Healing in Diabetic Mice, Molecules 26 (2021) 2554.
A.J. Morwood, I.A. El-Karim, S.A. Clarke, F.T. Lundy, The Role of Extracellular Matrix (ECM) Adhesion Motifs in Functionalised Hydrogels, Molecules 28 (2023) 4616.
S. Banasaz, V. Ferraro, Keratin from Animal By-Products: Structure, Characterization, Extraction and Application—A Review, Polymers 16 (2024) 1999.
O.A. Meko, S.O. Eraga, M.I. Arhewoh, Effect of extraction parameters on some properties of keratin obtained from waste chicken feathers, Trop. J. Nat. Prod. Res. 8(6) (2024) 7423-7430.
S.D. Marliyana, T.I.S.T. Dewi, T. Kusumaningsih, Extraction of ?-keratin from poultry feather waste using sodium metabisulfite and sodium dodecyl sulfate, Malays. J. Anal. Sci. 28(1) (2024) 116-126.
S. Banasaz, V. Ferraro, Keratin from animal by-products: structure, characterization, extraction and application—A review, Polymers 16(14) (2024) 1999.
M. Skerget, M. Colnik, L.F. Zemljic, L. Gradisnik, T.Z. Semren, B.T. Lovakovic, et al., Efficient and green isolation of keratin from poultry feathers by subcritical water, Polymers 15(12) (2023) 2658.
S.G. Giteru, D.H. Ramsey, Y. Hou, L. Cong, A. Mohan, A.E-D.A. Bekhit, Wool keratin as a novel alternative protein: A comprehensive review of extraction, purification, nutrition, safety, and food applications, Compr. Rev. Food Sci. Food Saf. 22(1) (2022) 643-87.
Y.S. Khoo, T.C. Tjong, J.W. Chew, X. Hu, Techniques for recovery and recycling of ionic liquids: A review, Sci Total Environ. 922 (2024) 171238.
R. Salas, R. Villa, F. Velasco, F.G. Cirujano, S. Nieto, N. Martin, et al., Ionic liquids in polymer technology, Green Chem. 27 (2025) 1620.
C.L.B. Reis, A.V.F. Carvalho, T.B.A.R. Miguel, E.C. Miguel, D.S. Zampieri, M.V.P. Rocha, et al., Green synthesis of choline-based ionic liquids and utilization in the extraction of biomolecules from Limnospira platensis microalgae, J. Appl. Phycol. 16(1) (2024) 151.
X. Lin, K. Jiang, X. Liu, D. Han, Review on development of ionic liquids in lignocellulosic biomass refining, J. Mol. Liq. 359(24) (2022) 119326.
F. Yang, C. Chen, D. Ni, Y. Yang, J. Tian, Y. Li, et al., Effects of fermentation on bioactivity and the composition of polyphenols contained in polyphenol-rich foods: A review, Foods 12(17) (2023) 3315.
N. Nayak, R.R. Bhujle, N.A. Nanje-Gowda, S. Chakraborty, K. Siliveru, J. Subbiah, et al., Advances in the novel and green-assisted techniques for extraction of bioactive compounds from millets: A comprehensive review, Heliyon 10 (2024) e30921.
M. Kammoun, A. Margellou, V.B. Toteva, A. Aladjadjiyan, A.F. Sousa, S.V. Luis, et al., The key role of pretreatment for the one-step and multi-step conversions of European lignocellulosic materials into furan compounds, RSC Adv. 13 (2023) 21587-21612.
R.S. Abolore, S. Jaiswal, A.K. Jaiswal, Green and sustainable pretreatment methods for cellulose extraction from lignocellulosic biomass and its applications: A review, Carbohydr. Polym. Technol. Appl. 7 (2024) 100396.
D. Kim, S-G. Kang, Y.K. Chang, M. Kwak, Two-step macromolecule separation process with acid pretreatment and high-shear-assisted extraction for microalgae-based biorefinery, Sustainability 16(17) (2024) 7589.
P. Bharmoria, A.A. Tietze, D. Mondal, T.S. Kang, A. Kumar, M.G. Freire, Do ionic liquids exhibit the required characteristics to dissolve, extract, stabilize, and purify proteins? Past-present-future assessment, Chem Rev. 124(6) (2024) 3037-3084.
S.K. Panja, S. Kumar, B. Haddad, A.R. Patel, D. Villemin, H-M Amine, et al., Role of multiple intermolecular H-bonding interactions in molecular cluster of hydroxyl-functionalized imidazolium ionic liquid: an experimental, topological, and molecular dynamics study, Physchem. 4(4) (2024) 369-388.
C. Polesca, A.A. Gatta, H. Passos, J.A.P. Coutinho, J.P. Hallett, M.G. Freire, Sustainable keratin recovery process using a bio-based ionic liquid aqueous solution and its techno-economic assessment, Green Chem. 25 (2023) 3995-4003.
A. Cordova, S. Catalan, V. Carrasco, F.O. Farias, J. Trentin, J. Lopez, et al., Sustainable assessment of ultrasound-assisted extraction of anthocyanins with bio-based solvents for upgrading grape pomace Cabernet Sauvignon derived from a winemaking process, Ultrason. Sonochem. 112 (2025) 107201.
S. Kong, Y. Liu, R. Tang, Q. Liao, D. Bai, D. Lv, et al., Ultrasound-assisted extraction of prenylated flavonoids from Sophora flavescens: Optimization, mechanistic characterization, antioxidant and anti-inflammatory activities, Ind. Crops Prod. 225 (2025) 120559.
F. Pourjavaheri, S.O. Pour, O.A.H. Jones, P.M. Smooker, R. Brklja?a, F. Sherkat, et al., Extraction of keratin from waste chicken feathers using sodium sulfide and l-cysteine, Process Biochem. 82 (2019) 205-214.
L. Machado-Carvalho, T. Martins, A. Aires, G. Marques, Optimization of Phenolic Compounds Extraction and Antioxidant Activity from Inonotus hispidus Using Ultrasound-Assisted ExtractionTechnology, Metabolites 13(4) (2023) 524.
D. Rosarina, R.N. Dimas, N.S.R. Chandra, E.F. Sari, H. Hermansyah, Optimization of Ultrasonic-Assisted Extraction (UAE) Method Using Natural Deep Eutectic Solvent (NADES) to Increase Curcuminoid Yield from Curcuma longa L., Curcuma xanthorrhiza, and Curcuma mangga Val., Molecules 27(18) (2022) 6080.
J. Sun, G.M. Santiago, F. Yan, W. Zhou, P. Rudolf, G. Portale, et al., Bioinspired Processing of Keratin into Upcycled Fibers through pH-Induced Coacervation, ACS Sustain. Chem. Eng. 11(5) (2023) 1985-1994.
A. Mengistu, G. Andualem, M. Abewaa, D. Birhane, Keratin extraction optimization from poultry feather using response surface- Box-Behnken experimental design method, Results Eng. 22 (2024) 102360.
S. Perez-Vila, M. Fenelon, D. Hennessy, J.A. O’Mahony, L.G. Gomez-Mascaraque, Impact of the extraction method on the composition and solubility of leaf protein concentrates from perennial ryegrass (Lolium perenne L.), Food Hydrocoll. 147(A) (2024) 109372.
K. Gulza, R.B. Arfi, K. Mougin, C. Vaulot, L. Michellin, L. Josien, et al., Development of novel and ecological keratin/cellulose-based composites for absorption of oils and organic solvents, Environ. Sci. Pollut. Res. 28 (2021) 46655–46668.
R.A. Pérez, B.Albero, Ultrasound-assisted extraction methods for the determination of organic contaminants in solid and liquid samples, Trends Anal. Chem. 166 (2023) 117204.
A.B.D. Nandiyanto, R. Oktiani, R. Ragadhita, How to Read and Interpret FTIR Spectroscope of Organic Material, Indones. J. Sci. Technol. 4(1) (2019) 97-118.
M. Skerget, M. Colnik, L.F. Zemljic, L. Gradinik, T.Z. Semren, B.T. Lovakovic, et al., Efficient and Green Isolation of Keratin from Poultry Feathers by Subcritical Water, Polymers 15(12) (2023) 2658-2658.
S. Alvarez, Development of innovative bio-based films with keratin extracted from duck feathers, Pau, France: Universite de Pau et des Pays de l’Adour, 2024.
J. Qiu, C. Wilkens, K. Barrett, A.S. Meyer, Microbial enzymes catalyzing keratin degradation: Classification, structure, function, Biotechnol. Adv. 44 (2020) 107607.
Y. Su, E.P. Hessou, E. Colobo, G. Belletti, A. Moussadik, I.T. Lucas, et al., Crystalline structures of l-cysteine and l-cystine: a combined theoretical and experimental characterization, Amino Acids 54(8) (2022) 1123-1133.
A. Henderson, L.M. Heaney, S. Rankin-Turner, Advancements in Ambient Ionisation Mass Spectrometry in2024: An Annual Review, Anal. Sci. Adv. 6 (2025) e7000.
R. Gunawan, A.B.D. Nandiyanto, How to Read and Interpret 1H-NMR and 13C-NMR Spectrums, Indones. J. Sci. Technol. 6(2) (2021) 267-298.
R. Wang, H. Tong, Preparation Methods and Functional Characteristics of Regenerated Keratin-Based Biofilms, Polymers 14(21) (2022) 4723.
N. Senthilkumar, S. Chowdhury, P. Sanpui, Extraction of keratin from keratinous wastes: current status and future directions, J. Mater. Cycles Waste Manag. 25 (2023) 1–16.
K. Zuniga, N. Ghousifam, J. Sansalone, K. Senecal, M.V. Dyke, M.N. Rylander, Keratin Promotes Differentiation of Keratinocytes Seeded on Collagen/Keratin Hydrogels, Bioengineering 9(10) (2022) 559.
Q. Chen, Y. Pei, M.G. Abu-Kaya, Structure, extraction, processing, and applications of collagen as an ideal component for biomaterials - a review, Collagen Leather 5(20) (2023).
M. Rajabi, A. Ali, M. McConnell, J. Cabral, Keratinous materials: Structures and functions in biomedical applications, Mater. Sci. Eng. C. 110 (2020) 110612.
Y. Rong, X. Liang, K. Jiang, H. Jia, H. Li, B. Lu, et al., Global Trendsin Research of Programmed Cell Deathin Osteoporosis: A bibliometric and Visualized Analysis (2000–2023), Orthop. Surg. 16 (2024) 1783-1800.
M.A. Clynes, N.C. Harvey, E.M. Curtis, N.R. Fuggle, E.M. Dennison, C. Cooper, The epidemiology of osteoporosis, Br. Med. Bull. 133(1) (2020) 105-117.
M.A. Clynes, L.D. Westbury, E.M. Dennison, J.A. Kanis, MK. Javaid, N.C. Harvey, et al., Bone densitometry worldwide: a global survey by the ISCD and IOF, Osteoporos. Int. 31 (2020) 1779-1786.
M. Zhang, R. Lin, X. Wang, J. Xue, C. Deng, C. Feng, et al., 3D printing of Haversian bone–mimicking scaffolds for multicellular delivery in bone regeneration, Sci. Adv. 6(12) (2020) eaaz6725.
H. Shanshan, K. Nie, J. Li, Q. Sun, X. Wang, X. Li, et al., 3D Electrospun Nanofiber-Based Scaffolds: From Preparation and Properties to Tissue Regeneration Applications, Stem Cells Int. 22 (2021) 8790143.
A.R. Khan, N. S. Grewal, Z. Jun, F.M.O. Tawfiq, F. Tchier, R.M. Zulqarnain, et al., Raising the Bar: Progress in 3D-Printed Hybrid Bone Scaffolds for Clinical Applications: A Review, Sage J. 33 (2024) 1-17.
M. Krishani, W.Y. Shin, H. Suhaimi, N.S. Sambudi, Development of Scaffolds from Bio-Based Natural Materials for Tissue Regeneration Applications: A Review, Gels 9 (2022) 100.
Y. Kim, S. Vijayavenkataraman, G. Cidonio, Biomaterials and scaffolds for tissue engineering and regenerative medicine, BMC Methods 1(2) (2024).
M.S.B. Reddy, D. Ponnamma, R. Choudhary, K.K. Sadasivuni, A Comparative Review of Natural and Synthetic Biopolymer Composite Scaffolds, Polymers 13 (2021) 1105.
A.E. Eldeeb, S. Salah, N.A. Elkasabgy, Biomaterials for Tissue Engineering Applications and Current Updates in the Field: A Comprehensive Review, AAPS PharmSciTech. 23 (2022) 267.
L.E. Rojas-Martíneza, C.G. Flores-Hernandeza, L.M. López-Marínb, A.L. Martinez-Hernandeza, S.B. Thoratc, C.D. Reyes Vasquez, et al., 3D printing of PLA composites scaffolds reinforced with keratin and chitosan: Effect of geometry and structure, Eur. Polym. J. 141 (2020) 110088.
H. Zhang, F. Su, X. Ma, G. Zhao, Brief introduction of keratin and its biological application, especially in drug delivery, Emerg. Mater. 4 (2021) 1225-1242.
J.E. Plowman, R.E. Miller, A. Thomas, A.J. Grosvenoer, D.P. Harland, S. Deb-Choudhury, Adetailed mapping of the readily accessible disulphide bonds in the cortex of wool fibres, Proteins 89 (2021) 708-720.
M. Konop, A.K. Laskowska, M. Rybka, E. Klodzinska, D. Sulejczak, R.A. Schwartz, Keratin Scaffolds Containing Casomorphin Stimulate Macrophage Infiltration and Accelerate Full-Thickness Cutaneous Wound Healing in Diabetic Mice, Molecules 26 (2021) 2554.
A.J. Morwood, I.A. El-Karim, S.A. Clarke, F.T. Lundy, The Role of Extracellular Matrix (ECM) Adhesion Motifs in Functionalised Hydrogels, Molecules 28 (2023) 4616.
S. Banasaz, V. Ferraro, Keratin from Animal By-Products: Structure, Characterization, Extraction and Application—A Review, Polymers 16 (2024) 1999.
O.A. Meko, S.O. Eraga, M.I. Arhewoh, Effect of extraction parameters on some properties of keratin obtained from waste chicken feathers, Trop. J. Nat. Prod. Res. 8(6) (2024) 7423-7430.
S.D. Marliyana, T.I.S.T. Dewi, T. Kusumaningsih, Extraction of ?-keratin from poultry feather waste using sodium metabisulfite and sodium dodecyl sulfate, Malays. J. Anal. Sci. 28(1) (2024) 116-126.
S. Banasaz, V. Ferraro, Keratin from animal by-products: structure, characterization, extraction and application—A review, Polymers 16(14) (2024) 1999.
M. Skerget, M. Colnik, L.F. Zemljic, L. Gradisnik, T.Z. Semren, B.T. Lovakovic, et al., Efficient and green isolation of keratin from poultry feathers by subcritical water, Polymers 15(12) (2023) 2658.
S.G. Giteru, D.H. Ramsey, Y. Hou, L. Cong, A. Mohan, A.E-D.A. Bekhit, Wool keratin as a novel alternative protein: A comprehensive review of extraction, purification, nutrition, safety, and food applications, Compr. Rev. Food Sci. Food Saf. 22(1) (2022) 643-87.
Y.S. Khoo, T.C. Tjong, J.W. Chew, X. Hu, Techniques for recovery and recycling of ionic liquids: A review, Sci Total Environ. 922 (2024) 171238.
R. Salas, R. Villa, F. Velasco, F.G. Cirujano, S. Nieto, N. Martin, et al., Ionic liquids in polymer technology, Green Chem. 27 (2025) 1620.
C.L.B. Reis, A.V.F. Carvalho, T.B.A.R. Miguel, E.C. Miguel, D.S. Zampieri, M.V.P. Rocha, et al., Green synthesis of choline-based ionic liquids and utilization in the extraction of biomolecules from Limnospira platensis microalgae, J. Appl. Phycol. 16(1) (2024) 151.
X. Lin, K. Jiang, X. Liu, D. Han, Review on development of ionic liquids in lignocellulosic biomass refining, J. Mol. Liq. 359(24) (2022) 119326.
F. Yang, C. Chen, D. Ni, Y. Yang, J. Tian, Y. Li, et al., Effects of fermentation on bioactivity and the composition of polyphenols contained in polyphenol-rich foods: A review, Foods 12(17) (2023) 3315.
N. Nayak, R.R. Bhujle, N.A. Nanje-Gowda, S. Chakraborty, K. Siliveru, J. Subbiah, et al., Advances in the novel and green-assisted techniques for extraction of bioactive compounds from millets: A comprehensive review, Heliyon 10 (2024) e30921.
M. Kammoun, A. Margellou, V.B. Toteva, A. Aladjadjiyan, A.F. Sousa, S.V. Luis, et al., The key role of pretreatment for the one-step and multi-step conversions of European lignocellulosic materials into furan compounds, RSC Adv. 13 (2023) 21587-21612.
R.S. Abolore, S. Jaiswal, A.K. Jaiswal, Green and sustainable pretreatment methods for cellulose extraction from lignocellulosic biomass and its applications: A review, Carbohydr. Polym. Technol. Appl. 7 (2024) 100396.
D. Kim, S-G. Kang, Y.K. Chang, M. Kwak, Two-step macromolecule separation process with acid pretreatment and high-shear-assisted extraction for microalgae-based biorefinery, Sustainability 16(17) (2024) 7589.
P. Bharmoria, A.A. Tietze, D. Mondal, T.S. Kang, A. Kumar, M.G. Freire, Do ionic liquids exhibit the required characteristics to dissolve, extract, stabilize, and purify proteins? Past-present-future assessment, Chem Rev. 124(6) (2024) 3037-3084.
S.K. Panja, S. Kumar, B. Haddad, A.R. Patel, D. Villemin, H-M Amine, et al., Role of multiple intermolecular H-bonding interactions in molecular cluster of hydroxyl-functionalized imidazolium ionic liquid: an experimental, topological, and molecular dynamics study, Physchem. 4(4) (2024) 369-388.
C. Polesca, A.A. Gatta, H. Passos, J.A.P. Coutinho, J.P. Hallett, M.G. Freire, Sustainable keratin recovery process using a bio-based ionic liquid aqueous solution and its techno-economic assessment, Green Chem. 25 (2023) 3995-4003.
A. Cordova, S. Catalan, V. Carrasco, F.O. Farias, J. Trentin, J. Lopez, et al., Sustainable assessment of ultrasound-assisted extraction of anthocyanins with bio-based solvents for upgrading grape pomace Cabernet Sauvignon derived from a winemaking process, Ultrason. Sonochem. 112 (2025) 107201.
S. Kong, Y. Liu, R. Tang, Q. Liao, D. Bai, D. Lv, et al., Ultrasound-assisted extraction of prenylated flavonoids from Sophora flavescens: Optimization, mechanistic characterization, antioxidant and anti-inflammatory activities, Ind. Crops Prod. 225 (2025) 120559.
F. Pourjavaheri, S.O. Pour, O.A.H. Jones, P.M. Smooker, R. Brklja?a, F. Sherkat, et al., Extraction of keratin from waste chicken feathers using sodium sulfide and l-cysteine, Process Biochem. 82 (2019) 205-214.
L. Machado-Carvalho, T. Martins, A. Aires, G. Marques, Optimization of Phenolic Compounds Extraction and Antioxidant Activity from Inonotus hispidus Using Ultrasound-Assisted ExtractionTechnology, Metabolites 13(4) (2023) 524.
D. Rosarina, R.N. Dimas, N.S.R. Chandra, E.F. Sari, H. Hermansyah, Optimization of Ultrasonic-Assisted Extraction (UAE) Method Using Natural Deep Eutectic Solvent (NADES) to Increase Curcuminoid Yield from Curcuma longa L., Curcuma xanthorrhiza, and Curcuma mangga Val., Molecules 27(18) (2022) 6080.
J. Sun, G.M. Santiago, F. Yan, W. Zhou, P. Rudolf, G. Portale, et al., Bioinspired Processing of Keratin into Upcycled Fibers through pH-Induced Coacervation, ACS Sustain. Chem. Eng. 11(5) (2023) 1985-1994.
A. Mengistu, G. Andualem, M. Abewaa, D. Birhane, Keratin extraction optimization from poultry feather using response surface- Box-Behnken experimental design method, Results Eng. 22 (2024) 102360.
S. Perez-Vila, M. Fenelon, D. Hennessy, J.A. O’Mahony, L.G. Gomez-Mascaraque, Impact of the extraction method on the composition and solubility of leaf protein concentrates from perennial ryegrass (Lolium perenne L.), Food Hydrocoll. 147(A) (2024) 109372.
K. Gulza, R.B. Arfi, K. Mougin, C. Vaulot, L. Michellin, L. Josien, et al., Development of novel and ecological keratin/cellulose-based composites for absorption of oils and organic solvents, Environ. Sci. Pollut. Res. 28 (2021) 46655–46668.
R.A. Pérez, B.Albero, Ultrasound-assisted extraction methods for the determination of organic contaminants in solid and liquid samples, Trends Anal. Chem. 166 (2023) 117204.
A.B.D. Nandiyanto, R. Oktiani, R. Ragadhita, How to Read and Interpret FTIR Spectroscope of Organic Material, Indones. J. Sci. Technol. 4(1) (2019) 97-118.
M. Skerget, M. Colnik, L.F. Zemljic, L. Gradinik, T.Z. Semren, B.T. Lovakovic, et al., Efficient and Green Isolation of Keratin from Poultry Feathers by Subcritical Water, Polymers 15(12) (2023) 2658-2658.
S. Alvarez, Development of innovative bio-based films with keratin extracted from duck feathers, Pau, France: Universite de Pau et des Pays de l’Adour, 2024.
J. Qiu, C. Wilkens, K. Barrett, A.S. Meyer, Microbial enzymes catalyzing keratin degradation: Classification, structure, function, Biotechnol. Adv. 44 (2020) 107607.
Y. Su, E.P. Hessou, E. Colobo, G. Belletti, A. Moussadik, I.T. Lucas, et al., Crystalline structures of l-cysteine and l-cystine: a combined theoretical and experimental characterization, Amino Acids 54(8) (2022) 1123-1133.
A. Henderson, L.M. Heaney, S. Rankin-Turner, Advancements in Ambient Ionisation Mass Spectrometry in2024: An Annual Review, Anal. Sci. Adv. 6 (2025) e7000.
R. Gunawan, A.B.D. Nandiyanto, How to Read and Interpret 1H-NMR and 13C-NMR Spectrums, Indones. J. Sci. Technol. 6(2) (2021) 267-298.
R. Wang, H. Tong, Preparation Methods and Functional Characteristics of Regenerated Keratin-Based Biofilms, Polymers 14(21) (2022) 4723.
N. Senthilkumar, S. Chowdhury, P. Sanpui, Extraction of keratin from keratinous wastes: current status and future directions, J. Mater. Cycles Waste Manag. 25 (2023) 1–16.
K. Zuniga, N. Ghousifam, J. Sansalone, K. Senecal, M.V. Dyke, M.N. Rylander, Keratin Promotes Differentiation of Keratinocytes Seeded on Collagen/Keratin Hydrogels, Bioengineering 9(10) (2022) 559.
Q. Chen, Y. Pei, M.G. Abu-Kaya, Structure, extraction, processing, and applications of collagen as an ideal component for biomaterials - a review, Collagen Leather 5(20) (2023).
M. Rajabi, A. Ali, M. McConnell, J. Cabral, Keratinous materials: Structures and functions in biomedical applications, Mater. Sci. Eng. C. 110 (2020) 110612.