{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T22:08:10Z","timestamp":1790806090483,"version":"4.1.0"},"reference-count":52,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2019,8,19]],"date-time":"2019-08-19T00:00:00Z","timestamp":1566172800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["31701543"],"award-info":[{"award-number":["31701543"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100017599","name":"Science and Technology Program of Zhejiang Province","doi-asserted-by":"publisher","award":["2017C32019"],"award-info":[{"award-number":["2017C32019"]}],"id":[{"id":"10.13039\/501100017599","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Protein hydrolysates from fish by-products have good process suitability and bioavailability in the food industry. The objective of this work was to develop a method for protein recovery from fish scales and evaluate the hydrolysis of the scale protein. The effect of the hydrothermal process on protein recovery, degree of hydrolysis (DH) and structural properties of the hydrolysates was investigated. Results showed that hydrothermal treatment could enhance protein recovery of tilapia scales without demineralization and dramatically improve the DH of the hydrolysates. The hydrothermal treated scales showed a better protein recovery (84.81%) and DH (12.88%) and released peptides more efficiently than that of the conventional treated samples. The obtained gelatin hydrolysates mainly distributed in the range of 200\u20132000 Da with an angiotensin I-converting enzyme (ACE) IC50 value of 0.73 mg\/mL. The ACE inhibitory activity of gelatin hydrolysates was stable under high temperature, pH and gastrointestinal proteases. Hydrothermal treatment followed by enzymatic hydrolysis offers a potential solution for preparation of gelatin hydrolysates for food ingredients from fish processing by-products.<\/jats:p>","DOI":"10.3390\/molecules24162998","type":"journal-article","created":{"date-parts":[[2019,8,19]],"date-time":"2019-08-19T06:10:14Z","timestamp":1566195014000},"page":"2998","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":62,"title":["Fish Scale Valorization by Hydrothermal Pretreatment Followed by Enzymatic Hydrolysis for Gelatin Hydrolysate Production"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5812-7942","authenticated-orcid":false,"given":"Yiqi","family":"Zhang","sequence":"first","affiliation":[{"name":"Institute of Seafood, Zhejiang Gongshang University, Hangzhou 310035, China"},{"name":"Key Laboratory of Aquatic Products Processing of Zhejiang Province, Hangzhou 310035, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dan","family":"Tu","sequence":"additional","affiliation":[{"name":"Institute of Seafood, Zhejiang Gongshang University, Hangzhou 310035, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qing","family":"Shen","sequence":"additional","affiliation":[{"name":"Institute of Seafood, Zhejiang Gongshang University, Hangzhou 310035, China"},{"name":"Key Laboratory of Aquatic Products Processing of Zhejiang Province, Hangzhou 310035, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhiyuan","family":"Dai","sequence":"additional","affiliation":[{"name":"Institute of Seafood, Zhejiang Gongshang University, Hangzhou 310035, China"},{"name":"Key Laboratory of Aquatic Products Processing of Zhejiang Province, Hangzhou 310035, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,8,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"7220","DOI":"10.1021\/acssuschemeng.7b01439","article-title":"Selective extraction of collagen peptides with high purity from cod skins by deep eutectic solvents","volume":"5","author":"Bai","year":"2017","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"316","DOI":"10.1016\/j.foodchem.2019.05.054","article-title":"Vacuum impregnation of fish gelatin combined with grape seed extract inhibits protein oxidation and degradation of chilled tilapia fillets","volume":"294","author":"Zhao","year":"2019","journal-title":"Food Chem."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"527","DOI":"10.1146\/annurev-food-031414-111800","article-title":"Collagen and gelatin","volume":"6","author":"Liu","year":"2015","journal-title":"Annu. Rev. Food Sci. Technol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"678","DOI":"10.1016\/j.lwt.2018.11.087","article-title":"Physicochemical and gel-forming properties of protein isolated from salmon, cod and herring by-products using the pH-shift method","volume":"101","author":"Abdollahi","year":"2019","journal-title":"LWT"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1016\/j.foodhyd.2019.03.041","article-title":"Combination of sodium alginate with tilapia fish gelatin for improved texture properties and nanostructure modification","volume":"94","author":"Sow","year":"2019","journal-title":"Food Hydrocolloid"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Huang, C.-Y., Wu, T.-C., Hong, Y.-H., Hsieh, S.-L., Guo, H.-R., and Huang, R.-H. (2018). Enhancement of cell adhesion, cell growth, wound healing, and oxidative protection by gelatins extracted from extrusion-pretreated tilapia (Oreochromis sp.) fish scale. Molecules, 23.","DOI":"10.3390\/molecules23102406"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Huang, C.-Y., Tsai, Y.-H., Hong, Y.-H., Hsieh, S.-L., and Huang, R.-H. (2018). Characterization and antioxidant and angiotensin I-converting enzyme (ACE)-inhibitory activities of gelatin hydrolysates prepared from extrusion-pretreated milkfish (Chanos chanos) scale. Mar. Drugs, 16.","DOI":"10.3390\/md16100346"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Tkaczewska, J., Bukowski, M., and Mak, P. (2018). Identification of antioxidant peptides in enzymatic hydrolysates of carp (Cyprinus carpio) skin gelatin. Molecules, 24.","DOI":"10.3390\/molecules24010097"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"916","DOI":"10.1016\/j.jclepro.2018.10.313","article-title":"A simple and eco-friendly method of gelatin production from bone: One-step biocatalysis","volume":"209","author":"Ma","year":"2019","journal-title":"J. Clean. Prod."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"6425","DOI":"10.1021\/acs.analchem.6b01013","article-title":"Subcritical water processing of proteins: An alternative to enzymatic digestion?","volume":"88","author":"Powell","year":"2016","journal-title":"Anal. Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1016\/j.supflu.2018.03.006","article-title":"Subcritical water hydrolysis for the production of bioactive peptides from tuna skin collagen","volume":"141","author":"Ahmed","year":"2018","journal-title":"J. Supercrit. Fluids"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.lwt.2017.04.073","article-title":"Potential application of static hydrothermal processing to produce the protein hydrolysates from porcine skin by-products","volume":"83","author":"Min","year":"2017","journal-title":"LWT-Food Sci. Technol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/j.ifset.2017.08.011","article-title":"Characterization of soy protein hydrolysates produced by varying subcritical water processing temperature","volume":"43","author":"Ramachandraiah","year":"2017","journal-title":"Innov. Food Sci. Emerg."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"350","DOI":"10.1016\/j.foodchem.2018.05.034","article-title":"Analysis of volatile compounds and nutritional properties of enzymatic hydrolysate of protein from cod bone","volume":"264","author":"Tan","year":"2018","journal-title":"Food Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"e12464","DOI":"10.1111\/jfbc.12464","article-title":"Functionality of porcine skin hydrolysates produced by hydrothermal processing for liposomal delivery system","volume":"42","author":"Choi","year":"2018","journal-title":"J. Food Biochem."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"7709","DOI":"10.1021\/acssuschemeng.7b01146","article-title":"Controlled conversion of proteins into high-molecular-weight peptides without additives with high-temperature water and fast heating rates","volume":"5","author":"Aida","year":"2017","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_17","unstructured":"Fishery and Fisheries Administration Bureau of Ministry of Agriculture and Rural Areas of the People\u2019s Republic of China (2019). China Fishery Statistical Yearbook."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"814","DOI":"10.1016\/j.foodchem.2015.11.044","article-title":"Element distribution and morphology of spotted golden goatfish fish scales as affected by demineralisation","volume":"197","author":"Chuaychan","year":"2016","journal-title":"Food Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"997","DOI":"10.1016\/j.foodchem.2015.06.066","article-title":"Isolation and characterization of fish scale collagen from tilapia (Oreochromis sp.) by a novel extrusion-hydro-extraction process","volume":"190","author":"Huang","year":"2016","journal-title":"Food Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"931","DOI":"10.1016\/j.foodhyd.2017.11.040","article-title":"Release kinetics of Tilapia scale collagen I peptides during tryptic hydrolysis","volume":"77","author":"Chen","year":"2018","journal-title":"Food Hydrocolloid"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1016\/j.foodhyd.2015.07.027","article-title":"Rapid isolation of high purity pepsin-soluble type I collagen from scales of red drum fish (Sciaenops ocellatus)","volume":"52","author":"Chen","year":"2016","journal-title":"Food Hydrocolloid"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1179","DOI":"10.1016\/j.foodchem.2011.05.099","article-title":"Characteristics of acid soluble collagen and pepsin soluble collagen from scale of spotted golden goatfish (Parupeneus heptacanthus)","volume":"129","author":"Matmaroh","year":"2011","journal-title":"Food Chem."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"C426","DOI":"10.1111\/j.1750-3841.2009.01202.x","article-title":"Effect of EDTA, HCl, and citric acid on Ca salt removal from Asian (silver) carp scales prior to gelatin extraction","volume":"74","author":"Wang","year":"2009","journal-title":"J. Food Sci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1015","DOI":"10.1002\/fsn3.488","article-title":"Temperature-dependent extraction kinetics of hydrolyzed collagen from scales of croaker fish using thermal extraction","volume":"5","author":"Olatunji","year":"2017","journal-title":"Food Sci. Nutr."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1016\/j.trac.2015.02.022","article-title":"Pressurized hot water extraction of bioactives","volume":"71","author":"Plaza","year":"2015","journal-title":"TrAC-Trend. Anal. Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"174","DOI":"10.1016\/j.cej.2014.11.005","article-title":"Effects of thermal hydrolysis on organic matter solubilization and anaerobic digestion of high solid sludge","volume":"264","author":"Xue","year":"2015","journal-title":"Chem. Eng. J."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Riaz, T., Zeeshan, R., Zarif, F., Ilyas, K., Muhammad, N., Safi, S.Z., Rahim, A., Rizvi, S.A.A., and Rehman, I.U. (2018). FTIR analysis of natural and synthetic collagen. Appl. Spectrosc. Rev., 1\u201344.","DOI":"10.1080\/05704928.2018.1426595"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"210","DOI":"10.1016\/j.foodchem.2016.03.047","article-title":"Angiotensin I-converting enzyme (ACE) inhibitory activity and structural properties of oven- and freeze-dried protein hydrolysate from fresh water fish (Cirrhinus mrigala)","volume":"206","author":"Elavarasan","year":"2016","journal-title":"Food Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2036","DOI":"10.1021\/acssuschemeng.5b00310","article-title":"Steam flash explosion assisted dissolution of keratin from feathers","volume":"3","author":"Zhang","year":"2015","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"254","DOI":"10.1021\/sc500621z","article-title":"Water and carbon dioxide: Green solvents for the extraction of collagen\/gelatin from marine sponges","volume":"3","author":"Barros","year":"2015","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1007\/s00449-013-1009-0","article-title":"Extraction and characterization of biocompatible hydroxyapatite from fresh water fish scales for tissue engineering scaffold","volume":"37","author":"Panda","year":"2014","journal-title":"Bioproc. Biosyst. Eng."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"258","DOI":"10.1016\/j.molliq.2017.02.083","article-title":"Investigation of ionic liquids as a pretreatment solvent for extraction of collagen biopolymer from waste fish scales using COSMO-RS and experiment","volume":"232","author":"Muhammad","year":"2017","journal-title":"J. Mol. Liq."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"488","DOI":"10.1016\/j.lwt.2016.06.048","article-title":"Heat and\/or ultrasound pretreatments motivated enzymolysis of corn gluten meal: Hydrolysis kinetics and protein structure","volume":"77","author":"Zhou","year":"2017","journal-title":"LWT-Food Sci. Technol."},{"key":"ref_34","first-page":"3358","article-title":"Water resistance and mechanical property improvement of tilapia (Tilapia zillii) scale gelatin films by dehydrated thermal treatment","volume":"52","author":"Weng","year":"2015","journal-title":"J. Food Sci. Tech."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"568","DOI":"10.1016\/j.foodchem.2017.09.045","article-title":"Sequential extraction of gel-forming proteins, collagen and collagen hydrolysate from gutted silver carp (Hypophthalmichthys molitrix), a biorefinery approach","volume":"242","author":"Abdollahi","year":"2018","journal-title":"Food Chem."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1016\/j.lwt.2018.01.041","article-title":"Clarification effect of collagen hydrolysate clarifier on chrysanthemum beverage","volume":"91","author":"Zhang","year":"2018","journal-title":"LWT"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Yu, Y., Fan, F., Wu, D., Yu, C., Wang, Z., and Du, M. (2018). Antioxidant and ACE inhibitory activity of enzymatic hydrolysates from Ruditapes philippinarum. Molecules, 23.","DOI":"10.3390\/molecules23051189"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1586","DOI":"10.1016\/j.procbio.2007.08.011","article-title":"Antihypertensive effect and purification of an ACE inhibitory peptide from sea cucumber gelatin hydrolysate","volume":"42","author":"Zhao","year":"2007","journal-title":"Process Biochem."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Guo, Y., Michael, N., Fonseca Madrigal, J., Sosa Aguirre, C., and Jauregi, P. (2019). Protein hydrolysate from Pterygoplichthys disjunctivus, armoured catfish, with high antioxidant activity. Molecules, 24.","DOI":"10.3390\/molecules24081628"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1016\/j.ultsonch.2016.11.008","article-title":"Effect of combined ultrasonic and alkali pretreatment on enzymatic preparation of angiotensin converting enzyme (ACE) inhibitory peptides from native collagenous materials","volume":"36","author":"Zhang","year":"2017","journal-title":"Ultrason. Sonochem."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"495","DOI":"10.17113\/ftb.52.04.14.3641","article-title":"ACE inhibitory and antioxidant activities of collagen hydrolysates from the ribbon jellyfish (Chrysaora sp.)","volume":"52","author":"Barzideh","year":"2014","journal-title":"Food Technol. Biotech."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Joel, C.H., Sutopo, C.C.Y., Prajitno, A., Su, J.-H., and Hsu, J.-L. (2018). Screening of angiotensin-I converting enzyme inhibitory peptides derived from Caulerpa lentillifera. Molecules, 23.","DOI":"10.3390\/molecules23113005"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"9586","DOI":"10.1021\/jf072669w","article-title":"Angiotensin I-converting enzyme-inhibitory peptides obtained from chicken collagen hydrolysate","volume":"56","author":"Saiga","year":"2008","journal-title":"J. Agric. Food. Chem."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"387","DOI":"10.1016\/j.foodchem.2009.04.015","article-title":"Macroporous resin purification of grass carp fish (Ctenopharyngodon idella) scale peptides with in vitro angiotensin-I converting enzyme (ACE) inhibitory ability","volume":"117","author":"Zhang","year":"2009","journal-title":"Food Chem."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1080\/10498850.2015.1094687","article-title":"Characterization of collagen enzymatic hydrolysates derived from lizardfish (Synodus fuscus) scales","volume":"26","author":"Chen","year":"2017","journal-title":"J. Aquat. Food Prod. Technol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"383","DOI":"10.1016\/j.foodchem.2016.07.145","article-title":"Fish skin gelatin hydrolysates produced by visceral peptidase and bovine trypsin: Bioactivity and stability","volume":"215","author":"Ketnawa","year":"2017","journal-title":"Food Chem."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1118","DOI":"10.1016\/j.foodchem.2012.05.080","article-title":"Gelatin hydrolysate from blacktip shark skin prepared using papaya latex enzyme: Antioxidant activity and its potential in model systems","volume":"135","author":"Kittiphattanabawon","year":"2012","journal-title":"Food Chem."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1535","DOI":"10.1021\/jf9033199","article-title":"Antioxidative and Angiotensin-I-Converting Enzyme Inhibitory Potential of a Pacific Hake (Merluccius productus) Fish Protein Hydrolysate Subjected to Simulated Gastrointestinal Digestion and Caco-2 Cell Permeation","volume":"58","author":"Samaranayaka","year":"2010","journal-title":"J. Agric. Food. Chem."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"2066","DOI":"10.1039\/C5FO01603G","article-title":"Enhancement of ACE and prolyl oligopeptidase inhibitory potency of protein hydrolysates from sardine and tuna by-products by simulated gastrointestinal digestion","volume":"7","author":"Batista","year":"2016","journal-title":"Food Funct."},{"key":"ref_50","unstructured":"AOAC (2000). Official Methods of Analysis, AOAC International. [17th ed.]."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"642","DOI":"10.1111\/j.1365-2621.2001.tb04614.x","article-title":"Improved method for determining food protein degree of hydrolysis","volume":"66","author":"Nielsen","year":"2001","journal-title":"J. Food Sci."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1016\/S0021-9673(02)00052-3","article-title":"Improved method for direct high-performance liquid chromatography assay of angiotensin-converting enzyme-catalyzed reactions","volume":"950","author":"Wu","year":"2002","journal-title":"J. Chromatogr. A"}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/24\/16\/2998\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:12:05Z","timestamp":1760188325000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/24\/16\/2998"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,8,19]]},"references-count":52,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2019,8]]}},"alternative-id":["molecules24162998"],"URL":"https:\/\/doi.org\/10.3390\/molecules24162998","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,8,19]]}}}