A review on collagen as a food supplement

Year 2022, Volume: 3 Issue: 1, 7 - 29, 01.12.2022

Fargana Musayeva Saniye Özcan Mustafa Sinan Kaynak

https://doi.org/10.37662/jpt.2022.1012432

Abstract

One of the most abundant proteins formed in the human body is collagen. It is responsible for the strength of body tissues in all cellular systems by establishing support networks. Collagen fibers are generally opaque and white, due to this reason they are easily recognized in the tissues. Collagen fibers, which are viscoelastic, have low extensibility and high tensile strength. The isoelectric point is around pH 5.8. Collagen is widely used as it helps blood coagulate, remodeling tissue. Although there are no known side effects, there is some concern about its role in inflammation, group-to-group variability, and possible disease transfection, given that animal-derived (natural) collagen is used in many clinical applications. Not every protein is of equal value, so not every collagen is of equal value. Thanks to its low molecular weight, hydrolyzed collagen is quickly digested by our body and enters our blood circulation. According to study, the most suitable type of collagen is the one in powder or liquid form for collagen peptides that can be easily absorbed and used by our body. Not every protein is of equal value, so not every collagen is of equal value. Thanks to its low molecular weight, hydrolyzed collagen is quickly digested by our body and enters our blood circulation. According to study, the most suitable type of collagen is the one in powder or liquid form for collagen peptides that can be easily absorbed and used by our body. It is necessary to rely on the most appropriate analysis technique to evaluate the quality feature. Techniques such as SEC, MS, HPLC and NMR are used to characterize complex peptide mixtures. Classical fibril-forming collagen includes collagen types I, II, III, V, and XI. These collagenes are characterized by their ability to aggregate into highly oriented supramolecular aggregates, forming fibrillar arrays with diameters between 25 and 400 nm. Being a natural protein and its technical characteristics, it is expected that development and consumption of collagen hydrolyzate will increase in the coming years. In this review, physical and chemical properties of collagen, types, pharmacology properties, quantity determination methods are briefly described.

Keywords

Analytical method, Collagen supplement, Collagen types, Drinkable collagen, Physicochemical properties

References

• [1] Y. Shigemura; S. Akaba; E. Kawashima; E. Y. Park; Y. Nakamura; K. Sato, Identification of a novel food-derived collagen peptide, hydroxyprolyl-glycine, in human peripheral blood by pre-column derivatisation with phenyl isothiocyanate. Food Chemistry 2011, 129 (3), 1019-1024. https://doi.org/10.1016/j.foodchem.2011.05.066
• [2] R. N. Raghavan; T. Muthukumar; N. Somanathan; T. Sastry, Biomimetic mineralization of novel silane crosslinked collagen. Materials Science and Engineering: C 2013, 33 (4), 1983-1988. https://doi.org/10.1016/j.msec.2013.01.007
• [3] C. Pinali, Cross-correlation of amino acid sequence data to explain fibril formation in a number of collagen subtypes. Cardiff University (United Kingdom): 2008. http://orca.cardiff.ac.uk/id/eprint/54916
• [4] K. Gelse; E. Pöschl; T. Aigner, Collagens—structure, function, and biosynthesis. Advanced drug delivery reviews 2003, 55 (12), 1531-1546. https://doi.org/10.1016/j.addr.2003.08.002
• [5] O. Prasad; L. Sinha; G. P. Gupta; N. Misra; C. Mehrotra; R. C. Agnihotri; J. Lal, Theoretical study of temperature induced transition and hyper stability of collagen mimics. Polymer 2006, 47 (5), 1674-1677. https://doi.org/10.1016/j.polymer.2006.01.010
• [6] C. Ding; M. Zhang; G. Li, Rheological properties of collagen/hydroxypropyl methylcellulose (COL/HPMC) blended solutions. Journal of Applied Polymer Science 2014, 131 (7). https://doi.org/10.1002/app.40042
• [7] J.-H. Chen; C.-W. Chiu; L.-C. Chen; S.-Y. Lai; C.-C. Lee, Conformational structure and aggregation behavior of poly [2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] in toluene/nonane solutions. Polymer 2012, 53 (21), 4843-4854. https://doi.org/10.1016/j.polymer.2012.08.048
• [8] X. Shi; W. Ma; C. Sun; S. Wu, The aggregation behavior of collagen in aqueous solution and its property of stabilizing liposomes in vitro. Biomaterials 2001, 22 (12), 1627-1634. https://doi.org/10.1016/S0142-9612(00)00320-3
• [9] K. Wu; W. Liu; G. Li, The aggregation behavior of native collagen in dilute solution studied by intrinsic fluorescence and external probing. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2013, 102, 186-193. https://doi.org/10.1016/j.saa.2012.10.048
• [10] W. Liu; G. Li, Non-isothermal kinetic analysis of the thermal denaturation of type I collagen in solution using isoconversional and multivariate non-linear regression methods. Polymer degradation and stability 2010, 95 (12), 2233-2240. https://doi.org/10.1016/j.polymdegradstab.2010.09.012
• [11] H. Hong; H. Fan; M. Chalamaiah; J. Wu, Preparation of low-molecular-weight, collagen hydrolysates (peptides): Current progress, challenges, and future perspectives. Food chemistry 2019, 301, 125222. https://doi.org/10.1016/j.foodchem.2019.125222
• [12] M. D. Shoulders; R. T. Raines, Collagen structure and stability. Annual review of biochemistry 2009, 78, 929-958. https://doi.org/10.1146/annurev.biochem.77.032207.120833
• [13] C. A. López‐Morales; S. Vázquez‐Leyva; L. Vallejo‐Castillo; G. Carballo‐Uicab; L. Muñoz‐García; J. E. Herbert‐Pucheta; L. G. Zepeda‐Vallejo; M. Velasco‐Velázquez; L. Pavón; S. M. Pérez‐Tapia, Determination of peptide profile consistency and safety of collagen hydrolysates as quality attributes. Journal of food science 2019, 84 (3), 430-439. https://doi.org/10.1111/1750-3841.14466
• [14] F. H. Silver; D. E. Birk, Molecular structure of collagen in solution: comparison of types I, II, III and V. International Journal of biological macromolecules 1984, 6 (3), 125-132. https://doi.org/10.1016/0141-8130(84)90052-7
• [15] Z. D’souza; T. J. Chettiankandy; M. S. Ahire; A. Thakur; S. G. Sonawane; A. Sinha, Collagen–structure, function and distribution in orodental tissues. Journal of Global Oral Health 2020, 2 (2), 134-139. DOI10.25259/JGOH_4_2020
• [16] K. Okuyama; K. Okuyama; S. Arnott; M. Takayanagi; M. Kakudo, Crystal and molecular structure of a collagen-like polypeptide (Pro-Pro-Gly) 10. Journal of molecular biology 1981, 152 (2), 427-443. https://doi.org/10.1016/0022-2836(81)90252-7
• [17] R. Z. Kramer; J. Bella; B. Brodsky; H. M. Berman, The crystal and molecular structure of a collagen-like peptide with a biologically relevant sequence. Journal of molecular biology 2001, 311 (1), 131-147. https://doi.org/10.1006/jmbi.2001.4849
• [18] D. L. Bodian; R. J. Radmer; S. Holbert; T. E. Klein, Molecular dynamics simulations of the full triple helical region of collagen type I provide an atomic scale view of the protein's regional heterogeneity. In Biocomputing 2011, World Scientific: 2011; pp 193-204. https://doi.org/10.1142/9789814335058_0021
• [19] J. K. Rainey; M. C. Goh, A statistically derived parameterization for the collagen triple‐helix. Protein Science 2002, 11 (11), 2748-2754. https://doi.org/10.1110/ps.0218502
• [20] Ü. Mustafa, Bound Water and Hydroxyproline are the essential contributors to collagen molecular stability: A Computational Analysis. Akademik Platform Mühendislik ve Fen Bilimleri Dergisi 7 (3), 373-380. doi:10.21541/apjes.515201
• [21] B. Balabanlı; Ş. Cevher; F. Küçük, Growth Factor-Collagen Relationship in Wound Healing. Gazi University Journal of Science 2015, 28 (2), 175-179.
• [22] S. ODABAŞ, Functional Polysaccharides Blended Collagen Cryogels. Hacettepe Journal of Biology and Chemistry 46 (1), 113-120. DOI:10.15671/HJBC.2018.219
• [23] T. Soydaş; E. Y. Saraç; S. Çınar; G. Yenmiş; S. Doğan; S. Solakoğlu; M. Tunçdemir; G. K. Sultuybek, Effects of Short-term High Glucose on nIH/3T3 Fibroblast Proliferation, Apoptosis, and Collagen Type I Production. Tıp Fakültesi Klinikleri Dergisi 2 (3), 91-95.
• [24] Ö. Ata; S. Tavman, KOLAJEN EKSTRAKSİYON YÖNTEMLERİNİN KARŞILAŞTIRILMASI. GIDA/The Journal of FOOD 2019, 44 (3). doi: 10.15237/gida.GD18112
• [25] S. Oesser; M. Adam; W. Babel; J. r. Seifert, Oral administration of 14C labeled gelatin hydrolysate leads to an accumulation of radioactivity in cartilage of mice (C57/BL). The Journal of nutrition 1999, 129 (10), 1891-1895. https://doi.org/10.1093/jn/129.10.1891
• [26] T. Tateya; I. Tateya; D. M. Bless, Immuno-scanning electron microscopy of collagen types I and III in human vocal fold lamina propria. Annals of Otology, Rhinology & Laryngology 2007, 116 (2), 156-159. https://doi.org/10.1177%2F000348940711600212
• [27] T. Sillat; R. Saat; R. Pöllänen; M. Hukkanen; M. Takagi; Y. T. Konttinen, Basement membrane collagen type IV expression by human mesenchymal stem cells during adipogenic differentiation. Journal of cellular and molecular medicine 2012, 16 (7), 1485-1495. https://doi.org/10.1111/j.1582-4934.2011.01442.
• [28] E. Koudouna; R. D. Young; M. Ueno; S. Kinoshita; A. J. Quantock; C. Knupp, Three-dimensional architecture of collagen type VI in the human trabecular meshwork. Molecular vision 2014, 20, 638. http://www.molvis.org/molvis/v20/638
• [29] K. Giannakakis; L. Massella; D. Grassetti; F. Dotta; M. Perez; A. O. Muda, Type VII collagen in Alport syndrome. Nephrology Dialysis Transplantation 2007, 22 (12), 3501-3507. https://doi.org/10.1093/ndt/gfm481
• [30] S. Grässel; R. J. Bauer, COL16A1 (collagen, type XVI, alpha 1). Atlas of Genetics and Cytogenetics in Oncology and Haematology 2012. DOI: 10.4267/2042/47532
• [31] M. I. Avila Rodríguez; L. G. Rodriguez Barroso; M. L. Sánchez, Collagen: A review on its sources and potential cosmetic applications. Journal of cosmetic dermatology 2018, 17 (1), 20-26. https://doi.org/10.1111/jocd.12450
• [32] R. Ylönen; T. Kyrönlahti; M. Sund; M. Ilves; P. Lehenkari; J. Tuukkanen; T. Pihlajaniemi, Type XIII collagen strongly affects bone formation in transgenic mice. Journal of Bone and Mineral Research 2005, 20 (8), 1381-1393. https://doi.org/10.1359/JBMR.050319
• [33] L. M. Shaw; B. R. Olsen, FACIT collagens: diverse molecular bridges in extracellular matrices. Trends in biochemical sciences 1991, 16, 191-194. https://doi.org/10.1016/0968-0004(91)90074-6
• [34] J. Seyer; R. Cancedda; M. van der Rest; B. R. Olsen, Tissue-specific expression of type XIV collagen–a member of the FACIT class of collagens. European journal of cell biology 1992, 59, 340-347.
• [35] S. Ricard-Blum, The collagen family. Cold Spring Harbor perspectives in biology 2011, 3 (1), a004978. doi: 10.1101/cshperspect.a004978
• [36] Z. Khiari; M. Ndagijimana; M. Betti, Low molecular weight bioactive peptides derived from the enzymatic hydrolysis of collagen after isoelectric solubilization/precipitation process of turkey by-products. Poultry science 2014, 93 (9), 2347-2362. https://doi.org/10.3382/ps.2014-03953
• [37] S. Wang; H. Hou; J. Hou; Y. Tao; Y. Lu; X. Yang; B. Li, Characterization of acid-soluble collagen from bone of pacific cod (Gadus macrocephalus). Journal of Aquatic Food Product Technology 2013, 22 (4), 407-420. https://doi.org/10.1080/10498850.2011.654382
• [38] S. Gamsjaeger; S. P. Robins; D. N. Tatakis; K. Klaushofer; E. P. Paschalis, Identification of pyridinoline trivalent collagen cross-links by Raman microspectroscopy. Calcified tissue international 2017, 100 (6), 565-574. DOI 10.1007/s00223-016-0232-5
• [39] Y. Zhang; Y. Chen; B. Zhao; J. Gao; L. Xia; F. Xing; Y. Kong; Y. Li; G. Zhang, Detection of Type I and III collagen in porcine acellular matrix using HPLC–MS. Regenerative Biomaterials 2020, 7 (6), 577-582. https://doi.org/10.1093/rb/rbaa032
• [40] N. BÖLGEN; Z. ÇETİNKAYA; D. DEMİR, FISH SKIN ISOLATED COLLAGEN CRYOGELS FOR TISSUE ENGINEERING APPLICATIONS: PURIFICATION, SYNTHESIS AND CHARACTERIZATION. Journal of the Turkish Chemical Society Section A: Chemistry 2016, 3 (3), 329-348. https://doi.org/10.18596/jotcsa.25993
• [41] M. Yazaki; Y. Ito; M. Yamada; S. Goulas; S. Teramoto; M.-a. Nakaya; S. Ohno; K. Yamaguchi, Oral ingestion of collagen hydrolysate leads to the transportation of highly concentrated Gly-Pro-Hyp and its hydrolyzed form of Pro-Hyp into the bloodstream and skin. Journal of Agricultural and Food Chemistry 2017, 65 (11), 2315-2322. https://doi.org/10.1021/acs.jafc.6b05679
• [42] C. E. Schmelzer; M. Getie; R. H. Neubert, Mass spectrometric characterization of human skin elastin peptides produced by proteolytic digestion with pepsin and thermitase. Journal of Chromatography A 2005, 1083 (1-2), 120-126. https://doi.org/10.1016/j.chroma.2005.06.034
• [43] L. Wang; Q. Wang; J. Qian; Q. Liang; Z. Wang; J. Xu; S. He; H. Ma, Bioavailability and bioavailable forms of collagen after oral administration to rats. Journal of agricultural and food chemistry 2015, 63 (14), 3752-3756. https://doi.org/10.1021/jf5057502
• [44] S. Pataridis; A. Eckhardt; K. Mikulikova; P. Sedláková; I. Miksik, Determination and quantification of collagen types in tissues using HPLC-MS/MS. Current analytical chemistry 2009, 5 (4), 316-323. https://doi.org/10.2174/157341109789077704
• [45] H. Ohara; H. Matsumoto; K. Ito; K. Iwai; K. Sato, Comparison of quantity and structures of hydroxyproline-containing peptides in human blood after oral ingestion of gelatin hydrolysates from different sources. Journal of agricultural and food chemistry 2007, 55 (4), 1532-1535. https://doi.org/10.1021/jf062834s
• [46] Y. Taga; M. Kusubata; K. Ogawa-Goto; S. Hattori, Highly accurate quantification of hydroxyproline-containing peptides in blood using a protease digest of stable isotope-labeled collagen. Journal of Agricultural and Food Chemistry 2014, 62 (50), 12096-12102. https://doi.org/10.1021/jf5039597
• [47] J. Wang; D. Luo; M. Liang; T. Zhang; X. Yin; Y. Zhang; X. Yang; W. Liu, Spectrum-effect relationships between high-performance liquid chromatography (HPLC) fingerprints and the antioxidant and anti-inflammatory activities of collagen peptides. Molecules 2018, 23 (12), 3257. https://doi.org/10.3390/molecules23123257
• [48] V. de Melo Oliveira; C. R. D. de Assis; B. d. A. M. da Costa; R. C. de Araújo Neri; F. T. D. do Monte; H. M. S. da Costa Vasconcelos; R. C. P. França; J. F. dos Santos; R. de Souza Bezerra; A. L. F. Porto, Physical, biochemical, densitometric and spectroscopic techniques for characterization collagen from alternative sources: A review based on the sustainable valorization of aquatic by-products. Journal of Molecular Structure 2020, 129023. https://doi.org/10.1016/j.procbio.2021.06.013
• [49] B. Qiu; F. Wei; X. Sun; X. Wang; B. Duan; C. Shi; J. Zhang; J. Zhang; W. Qiu; W. Mu, Measurement of hydroxyproline in collagen with three different methods. Molecular medicine reports 2014, 10 (2), 1157-1163. https://doi.org/10.3892/mmr.2014.2267
• [50] J. Robin, Methods for measuring hydroxyproline and estimating in vivo rates of collagen synthesis and degradation. In Fibrosis Research, Springer: 2005; pp 189-207. DOI: 10.1385/1-59259-940-0:189
• [51] V. A. Kumar; N. L. Taylor; A. A. Jalan; L. K. Hwang; B. K. Wang; J. D. Hartgerink, A nanostructured synthetic collagen mimic for hemostasis. Biomacromolecules 2014, 15 (4), 1484-1490. https://doi.org/10.1021/bm500091e
• [52] S. E. Bilek; S. K. Bayram, Kolajen Hidrolizatının Fonksiyonel Bir Bileşen Olarak Gıda Endüstrisinde Kullanılması. Academic Food Journal/Akademik GIDA 2015, 13 (4).
• [53] K. Iwai; T. Hasegawa; Y. Taguchi; F. Morimatsu; K. Sato; Y. Nakamura; A. Higashi; Y. Kido; Y. Nakabo; K. Ohtsuki, Identification of food-derived collagen peptides in human blood after oral ingestion of gelatin hydrolysates. Journal of agricultural and food chemistry 2005, 53 (16), 6531-6536. https://doi.org/10.1021/jf050206p
• [54] J. Wu; M. Fujioka; K. Sugimoto; G. Mu; Y. Ishimi, Assessment of effectiveness of oral administration of collagen peptide on bone metabolism in growing and mature rats. Journal of bone and mineral metabolism 2004, 22 (6), 547-553. DOI 10.1007/s00774-004-0522-2
• [55] M. Borumand; S. Sibilla, Daily consumption of the collagen supplement Pure Gold Collagen® reduces visible signs of aging. Clinical Interventions in Aging 2014, 9, 1747. https://doi.org/10.2147/CIA.S246397
• [56] D. Matthews; L. Laster, Absorption of protein digestion products: a review. Gut 1965, 6 (5), 411. https://dx.doi.org/10.1136%2Fgut.6.5.411
• [57] H. Daniel, Molecular and integrative physiology of intestinal peptide transport. Annu. Rev. Physiol. 2004, 66, 361-384. https://doi.org/10.1146/annurev.physiol.66.032102.144149
• [58] Y. Sai; M. Kajita; I. Tamai; J. Wakama; T. Wakamiya; A. Tsuji, Adsorptive-mediated endocytosis of a basic peptide in enterocyte-like Caco-2 cells. American Journal of Physiology-Gastrointestinal and Liver Physiology 1998, 275 (3), G514-G520. https://doi.org/10.1152/ajpgi.1998.275.3.G514
• [59] A. Adson; T. J. Raub; P. S. Burton; C. L. Barsuhn; A. R. Hilgers; K. L. Audus; N. F. Ho, Quantitative approaches to delineate paracellular diffusion in cultured epithelial cell monolayers. Journal of pharmaceutical sciences 1994, 83 (11), 1529-1536. https://doi.org/10.1002/jps.2600831103
• [60] M. Aito‐Inoue; D. Lackeyram; M. Z. Fan; K. Sato; Y. Mine, Transport of a tripeptide, Gly‐Pro‐Hyp, across the porcine intestinal brush‐border membrane. Journal of peptide science: an official publication of the European Peptide Society 2007, 13 (7), 468-474. https://doi.org/10.1002/jps.2600831103
• [61] M. Watanabe-Kamiyama; M. Shimizu; S. Kamiyama; Y. Taguchi; H. Sone; F. Morimatsu; H. Shirakawa; Y. Furukawa; M. Komai, Absorption and effectiveness of orally administered low molecular weight collagen hydrolysate in rats. Journal of agricultural and food chemistry 2010, 58 (2), 835-841. https://doi.org/10.1021/jf9031487
• [62] M. Tanaka; Y.-i. Koyama; Y. Nomura, Effects of collagen peptide ingestion on UV-B-induced skin damage. Bioscience, biotechnology, and biochemistry 2009, 73 (4), 930-932. https://doi.org/10.1271/bbb.80649
• [63] S. Yamamoto; F. Hayasaka; K. Deguchi; T. Okudera; T. Furusawa; Y. Sakai, Absorption and plasma kinetics of collagen tripeptide after peroral or intraperitoneal administration in rats. Bioscience, Biotechnology, and Biochemistry 2015, 79 (12), 2026-2033. https://doi.org/10.1080/09168451.2015.1062711
• [64] S. B. Sontakke; J.-h. Jung; Z. Piao; H. J. Chung, Orally available collagen tripeptide: enzymatic stability, intestinal permeability, and absorption of Gly-Pro-Hyp and Pro-Hyp. Journal of agricultural and food chemistry 2016, 64 (38), 7127-7133. https://doi.org/10.1021/acs.jafc.6b02955
• [65] A. J. Kleinnijenhuis; F. L. van Holthoon; A. J. Maathuis; B. Vanhoecke; J. Prawitt; F. Wauquier; Y. Wittrant, Non-targeted and targeted analysis of collagen hydrolysates during the course of digestion and absorption. Analytical and bioanalytical chemistry 2020, 412 (4), 973-982. https://doi.org/10.1007/s00216-019-02323-x
• [66] Z. D’SOUZA; T. Chettiankandy; M. Ahire; A. Thakur; S. Sonawane; A. Sinha, Collagen–structure, function and distribution in orodental tissues. Journal of Global Oral Health 2020, 2, 134-139.
• [67] J. W. Lash; K. Rosene; R. R. Minor; J. C. Daniel; R. A. Kosher, Environmental enhancement of in vitro chondrogenesis: III. The influence of external potassium lons and chondrogenic differentiation. Developmental biology 1973, 35 (2), 370-375. https://doi.org/10.1016/0012-1606(73)90032-8
• [68] B. Baum; J. Moss; S. Breul; R. Crystal, Association in normal human fibroblasts of elevated levels of adenosine 3 ‘: 5 ‘-monophosphate with a selective decrease in collagen production. Journal of Biological Chemistry 1978, 253 (10), 3391-3394. https://doi.org/10.1016/S0021-9258(17)34812-3
• [69] W. W.-Y. Kao; R. A. Berg; D. J. Prockop, Ascorbate increases the synthesis of procollagen hydroxyproline by cultured fibroblasts from chick embryo tendons without activation or prolyl hydroxylase. Biochimica et Biophysica Acta (BBA)-General Subjects 1975, 411 (2), 202-215. https://doi.org/10.1016/0304-4165(75)90300-1
• [70] R. Minor, Collagen metabolism: a comparison of diseases of collagen and diseases affecting collagen. The American journal of pathology 1980, 98 (1), 225.
• [71] W. v. B. Robertson, Metabolism of collagen in mammalian tissues. Biophysical journal 1964, 4 (1), 93-106. https://doi.org/10.1016/S0006-3495(64)86930-7
• [72] M. E. Nimni In Collagen: structure, function, and metabolism in normal and fibrotic tissues, Seminars in arthritis and rheumatism, Elsevier: 1983; pp 1-86. https://doi.org/10.1016/0049-0172(83)90024-0
• [73] E. Karna; L. Szoka; T. Y. L. Huynh; J. A. Palka, Proline-dependent regulation of collagen metabolism. Cellular and Molecular Life Sciences 2020, 77 (10), 1911-1918. https://doi.org/10.1007/s00018-019-03363-3
• [74] G. Wu; F. W. Bazer; R. C. Burghardt; G. A. Johnson; S. W. Kim; D. A. Knabe; P. Li; X. Li; J. R. McKnight; M. C. Satterfield, Proline and hydroxyproline metabolism: implications for animal and human nutrition. Amino acids 2011, 40 (4), 1053-1063. DOI 10.1007/s00726-010-0715-z
• [75] T. Herzinger; C. Schirren; C. Sander; T. Jansen; P. Kind, Reactive perforating collagenosis–transepidermal elimination of type IV collagen. Clinical and experimental dermatology 1996, 21 (4), 279-282. https://doi.org/10.1111/j.1365-2230.1996.tb00094.x
• [76] J. Myllyharju; K. I. Kivirikko, Collagens and collagen-related diseases. Annals of medicine 2001, 33 (1), 7-21. https://doi.org/10.3109/07853890109002055
• [77] R. W. Moskowitz In Role of collagen hydrolysate in bone and joint disease, Seminars in arthritis and rheumatism, Elsevier: 2000; pp 87-99. https://doi.org/10.1053/sarh.2000.9622
• [78] M. Nicklas; W. Schatton; S. Heinemann; T. Hanke; J. Kreuter, Enteric coating derived from marine sponge collagen. Drug development and industrial pharmacy 2009, 35 (11), 1384-1388. https://doi.org/10.3109/03639040902939239
• [79] A. Neklyudov; A. Berdutina; A. Ivankin; S. Mitaleva; E. Evstaf'eva, Collagen fractions obtained by water–salt extraction from raw materials of animal origin. Applied Biochemistry and Microbiology 2003, 39 (4), 426-430.
• [80] M. H. Yuswan; N. H. A. Jalil; H. Mohamad; S. Keso; N. A. Mohamad; T. S. T. M. Yusoff; N. F. Ismail; Y. N. A. Manaf; A. M. Hashim; M. N. M. Desa, Hydroxyproline determination for initial detection of halal-critical food ingredients (gelatin and collagen). Food chemistry 2020, 337, 127762. https://doi.org/10.1016/j.foodchem.2020.127762
• [81] P. Hashim; M. M. Ridzwan; J. Bakar; M. D. Hashim, Collagen in food and beverage industries. International Food Research Journal 2015, 22 (1), 1. https://doi.org/10.1016/j.foodchem.2020.127762