{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T02:58:50Z","timestamp":1780628330623,"version":"3.54.1"},"reference-count":48,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2019,10,21]],"date-time":"2019-10-21T00:00:00Z","timestamp":1571616000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"\u0420\u043e\u0441\u0441\u0438\u0439\u0441\u043a\u0438\u0439 \u0424\u043e\u043d\u0434 \u0424\u0443\u043d\u0434\u0430\u043c\u0435\u043d\u0442\u0430\u043b\u044c\u043d\u044b\u0445 \u0418\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u043d\u0438\u0439 (\u0420\u0424\u0424\u0418)","award":["19-016-00118"],"award-info":[{"award-number":["19-016-00118"]}]},{"DOI":"10.13039\/501100006769","name":"Russian Science Foundation","doi-asserted-by":"publisher","award":["16-16-00076"],"award-info":[{"award-number":["16-16-00076"]}],"id":[{"id":"10.13039\/501100006769","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Gelatin (G) was extracted from the skin of Atlantic cod at different pH of the aqueous phase (pH 3, 4, 5, 8 and 9) and at a temperature of 50 \u00b1 1 \u00b0C. The yield of gelatin (G3, G4, G5, G8, and G9, respectively) was 49\u201355% of the dry raw material. The influence of extraction pH on the physicochemical and functional properties of gelatin was studied. Sample G5 was characterized by higher protein content (92.8%) while lower protein content was obtained for sample G3 (86.5%) extracted under more aggressive conditions. Analysis of the molecular weight distribution showed the presence of \u03b1- and \u03b2-chains as major components; the molecular weight of the samples ranged between 130 and 150 kDa, with sample G5 having the highest molecular weight. IR spectra of all samples had absorption bands characteristic of fish gelatin. The study of the secondary structure demonstrated higher amounts of ordered triple collagen-like helices for G5 extracted under mild conditions. Accordingly, sample G5 formed gels with high values for the storage modulus and gelling and melting temperatures, which decrease as pH changes into acidic or alkaline regions. In addition, the differential scanning calorimetry data showed that G5 had a higher glass transition temperature and melting enthalpy. Thus, cod skin is an excellent source of gelatin with the necessary physicochemical and functional properties, depending on the appropriate choice of aqueous phase pH for the extraction.<\/jats:p>","DOI":"10.3390\/polym11101724","type":"journal-article","created":{"date-parts":[[2019,10,21]],"date-time":"2019-10-21T11:37:55Z","timestamp":1571657875000},"page":"1724","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":72,"title":["Tailoring Cod Gelatin Structure and Physical Properties with Acid and Alkaline Extraction"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5871-9320","authenticated-orcid":false,"given":"Svetlana R.","family":"Derkach","sequence":"first","affiliation":[{"name":"Department of Chemistry, Murmansk State Technical University, Sportivnaya str., 13, 183010 Murmansk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuliya A.","family":"Kuchina","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Murmansk State Technical University, Sportivnaya str., 13, 183010 Murmansk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrey V.","family":"Baryshnikov","sequence":"additional","affiliation":[{"name":"Laboratory of Biochemistry and Technology, Polar branch of Russian Federal Research Institute of Fisheries and Oceanography, Academician Knipovich str., 6, 183038 Murmansk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daria S.","family":"Kolotova","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Murmansk State Technical University, Sportivnaya str., 13, 183010 Murmansk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nikolay G.","family":"Voron\u2019ko","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Murmansk State Technical University, Sportivnaya str., 13, 183010 Murmansk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,10,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/j.foodhyd.2016.12.031","article-title":"Confectionery gels: Effects of low calorie sweeteners on the rheological properties and microstructure of fish gelatin","volume":"67","author":"Cai","year":"2017","journal-title":"Food Hydrocolloids"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1813","DOI":"10.1016\/j.foodhyd.2011.02.007","article-title":"Functional and bioactive properties of collagen and gelatin from alternative sources: A review","volume":"25","author":"Gimenez","year":"2011","journal-title":"Food hydrocolloids"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Schrieber, R., and Gareis, H. (2007). Gelatin Handbook. Theory and Industrial Practice, Wiley-VCH Verlag GmbH & Co. KGaA.","DOI":"10.1002\/9783527610969"},{"key":"ref_4","first-page":"47","article-title":"Review of Fish Gelatin Extraction, Properties and Packaging Applications","volume":"56","author":"Mahmood","year":"2016","journal-title":"Food Sci. Qual. Management"},{"key":"ref_5","first-page":"135","article-title":"Gelatin, source, extraction and industrial applications","volume":"12","author":"Mariod","year":"2013","journal-title":"Acta Sci. Pol. Tech. Aliment."},{"key":"ref_6","unstructured":"Veis, A. (1964). The Macromolecular Chemistry of Gelatin, Academic Press."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"347","DOI":"10.1016\/j.foodchem.2013.01.017","article-title":"Comparison between gelatines extracted from mackerel and blue whiting bones after pre-treatments","volume":"139","author":"Khiari","year":"2013","journal-title":"Food Chem."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1016\/j.lwt.2018.02.019","article-title":"Multiplex PCR to discriminate bovine, porcine, and fish DNA in gelatin and confectionery products","volume":"92","author":"Sultana","year":"2018","journal-title":"LWT Food Sci. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1016\/S0268-005X(99)00050-8","article-title":"Rheological characterization of gelatins from mammalian and marine sources","volume":"14","author":"Gilsenan","year":"2000","journal-title":"Food Hydrocolloids"},{"key":"ref_10","unstructured":"Grand View Research (2019, March 18). Gelatin market size expected to reach $4.08 billion by 2024. Available online: https:\/\/www.grandviewresearch.com\/press-release\/global-gelatin-market."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1680","DOI":"10.1016\/j.foodres.2013.09.026","article-title":"Chemical and biophysical properties of gelatins extracted from alkali-pretreated skin of cuttlefish (Sepia officinalis) using pepsin","volume":"54","author":"Jridi","year":"2013","journal-title":"Food Res. Int."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1016\/j.foodhyd.2008.07.002","article-title":"Fish gelatin: Properties, challenges, and prospects as an alternative to mammalian gelatins","volume":"23","author":"Karim","year":"2009","journal-title":"Food Hydrocolloids"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1111\/j.1750-3841.2006.00065.x","article-title":"Properties of Alaska pollock skin gelatin: A comparison with tilapia and pork skin gelatins","volume":"71","author":"Zhou","year":"2006","journal-title":"J. Food Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1016\/j.foodchem.2007.10.079","article-title":"Thermal characterisation of gelatin extracted from yellowfin tuna skin and commercial mammalian gelatin","volume":"108","author":"Rahman","year":"2008","journal-title":"Food Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1016\/j.lwt.2018.12.012","article-title":"Alcalase-assisted production of fish skin gelatin rich in high molecular weight (HMW) polypeptide chains and their characterization for film forming capacity","volume":"110","author":"Zhang","year":"2019","journal-title":"LWT Food Sci. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1016\/j.lwt.2018.11.046","article-title":"Effect of confectionery solutes on the rheological properties of fish (Oncorhynchus mykiss) gelatin","volume":"101","author":"Kamer","year":"2019","journal-title":"LWT Food Sci. Technol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"416","DOI":"10.1016\/j.foodres.2014.05.070","article-title":"African catfish (Clarias gariepinus) skin gelatin: Extraction optimization and physical\u2013chemical properties","volume":"65","author":"Alfaro","year":"2014","journal-title":"Food Res. Int."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1702","DOI":"10.1016\/j.foodhyd.2009.01.008","article-title":"Structural and mechanical properties of fish gelatin as a function of extraction conditions","volume":"23","author":"Eysturskard","year":"2009","journal-title":"Food Hydrocolloids"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"580","DOI":"10.1016\/j.lwt.2014.02.026","article-title":"Characteristics and chemical composition of skins gelatin from cobia (Rachycentron canadum)","volume":"57","author":"Silva","year":"2014","journal-title":"LWT Food Sci. Technol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/S0268-005X(01)00035-2","article-title":"Structural and physical properties of gelatin extracted from marine species: a comparative study","volume":"16","author":"Turnay","year":"2002","journal-title":"Food Hydrocolloids"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1016\/j.tifs.2017.08.012","article-title":"An overview of gelatin derived from aquatic animals: Properties and modification","volume":"68","author":"Lin","year":"2017","journal-title":"Trends Food Sci. Tech."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.fbio.2015.12.005","article-title":"Comparison of collagen and gelatin extracted from the skins of Nile tilapia (Oreochromis niloticus) and channel cat fish (Ictalurus punctatus)","volume":"13","author":"Zhang","year":"2016","journal-title":"Food Biosci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1016\/j.foodhyd.2017.05.004","article-title":"Influence of extraction variables on the structure and physical properties of salmon gelatin","volume":"71","author":"Flores","year":"2017","journal-title":"Food Hydrocolloids"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"643","DOI":"10.1016\/j.colsurfa.2017.06.032","article-title":"Gelatin prepared from European eel (Anguilla anguilla) skin: physicochemical, textural, viscoelastic and surface properties","volume":"529","author":"Sila","year":"2017","journal-title":"Colloid Surf. A"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/j.biortech.2005.11.021","article-title":"Extraction and characterization of gelatin from Altantic salmon (Salmo salar) skin","volume":"98","author":"Arnesen","year":"2007","journal-title":"Bioresour. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1016\/j.carbpol.2018.05.063","article-title":"Molecular structure and properties of \u03ba-carrageenan-gelatin gels","volume":"197","author":"Derkach","year":"2018","journal-title":"Carbohydr. Polym."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1093\/chromsci\/19.5.259","article-title":"A method for quantitative amino acid analysis using precolumn o-phthalaldehyde derivatization and high performance liquid chromatography","volume":"19","author":"Brent","year":"1981","journal-title":"J. Chromatogr. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"700","DOI":"10.1016\/j.foodchem.2007.08.071","article-title":"Effect of extracting time and temperature on yield of gelatin from fish offal","volume":"107","author":"Moore","year":"2008","journal-title":"Food Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1016\/j.chroma.2006.09.039","article-title":"Improved and simplified liquid chromatography\/atmospheric pressure chemical ionization mass spectrometry method for the analysis of underivatized free amino acids in various foods","volume":"1135","author":"Ozcan","year":"2006","journal-title":"J. Chromatogr. A"},{"key":"ref_30","unstructured":"Westermeier, R. (1993). Electrophoresis in Practice, John Wiley & Sons."},{"key":"ref_31","unstructured":"Rabek, J.F. (1983). Experimental methods in polymer chemistry. Physical principles and applications, John Wiley & Sons."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"549","DOI":"10.1111\/j.1745-7270.2007.00320.x","article-title":"Fourier Transform Infrared Spectroscopic Analysis of Protein Secondary Structures","volume":"39","author":"Kong","year":"2007","journal-title":"Acta Bioch. Bioph. Sin."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1016\/0966-7822(96)00003-2","article-title":"Infrared study of gelatin conformations in the gel and sol states","volume":"4","author":"Prystupa","year":"1996","journal-title":"Polym. Gels Netw."},{"key":"ref_34","unstructured":"Malkin, A.Y., and Isayev, A.I. (2017). Rheology: Concept, Methods, and Applications, ChemTec Publishing."},{"key":"ref_35","unstructured":"GOST 11293\u201389 (2008). Gelatin. Tekhnicheskie Usloviya [State Standard 11293\u201389. Gelatin. Technical Specification], Standartinform Publ.. (In Russian)."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1016\/j.lwt.2015.10.029","article-title":"Gelatin from clown featherback skin: Extraction conditions","volume":"66","author":"Kittiphattanabawon","year":"2016","journal-title":"LWT Food Sci. Technol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1016\/j.foodhyd.2016.08.007","article-title":"Recent advances on the role of process variables affecting gelatin yield and characteristics with special reference to enzymatic extraction: A review","volume":"63","author":"Ahmad","year":"2017","journal-title":"Food Hydrocolloids"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1016\/j.ijbiomac.2014.11.024","article-title":"Molecular characteristics and properties of gelatin from skin of seabass with sizes","volume":"73","author":"Sinthusamran","year":"2015","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_39","unstructured":"Silverstein, R.M., Vebster, F.X., and Kiemle, D.J. (2005). Spectrometric Identification of Organic Compounds, John Wiley & Sons. [7th ed.]."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Stuart, B. (2004). Infrared Spectroscopy: Fundamentals and Application, John Wiley & Sons.","DOI":"10.1002\/0470011149"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"3303","DOI":"10.1021\/bi00465a022","article-title":"Protein secondary structures in water from second-derivative Amide I infrared spectra","volume":"29","author":"Dong","year":"1990","journal-title":"Biochemistry"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1749","DOI":"10.1002\/bip.360271105","article-title":"Fourier transform IR spectroscopy of collagen and gelatin solution: deconvolution of the amide I band for conformational studies","volume":"27","author":"Payne","year":"1988","journal-title":"Biopolymers"},{"key":"ref_43","first-page":"73","article-title":"Gelation in gelatin and gelatin-containing multicomponent blends","volume":"46","author":"Izmailova","year":"2004","journal-title":"Polymer Sci. C"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1016\/S0268-005X(03)00065-1","article-title":"Physical and rheological properties of fish gelatin compared to mammalian gelatin","volume":"18","author":"Haug","year":"2004","journal-title":"Food Hydrocolloids"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"924","DOI":"10.1016\/j.lwt.2015.09.024","article-title":"Characteristics and functional properties of gelatin extracted from squid (Loligo vulgaris) skin","volume":"65","author":"Abdelmalek","year":"2015","journal-title":"LWT Food Sci. Technol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1093","DOI":"10.1111\/ijfs.12067","article-title":"Preparation and functional characterization of fish skin gelatin and comparison with commercial gelatin","volume":"48","author":"Rawdkuen","year":"2013","journal-title":"Int. J. Food Sci. Tech."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1016\/j.foodhyd.2012.04.001","article-title":"Characteristics and functional properties of gelatin from splendid squid (Loligo formosana) skin as affected by extraction temperatures","volume":"29","author":"Nagarajan","year":"2012","journal-title":"Food Hydrocolloids"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"5675","DOI":"10.1016\/j.biomaterials.2004.01.033","article-title":"Relationship between triple-helix content and mechanical properties of gelatin films","volume":"25","author":"Bigi","year":"2004","journal-title":"Biomaterials"}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/11\/10\/1724\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:28:07Z","timestamp":1760189287000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/11\/10\/1724"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,10,21]]},"references-count":48,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2019,10]]}},"alternative-id":["polym11101724"],"URL":"https:\/\/doi.org\/10.3390\/polym11101724","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,10,21]]}}}