{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,11]],"date-time":"2026-05-11T04:22:45Z","timestamp":1778473365929,"version":"3.51.4"},"reference-count":54,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2023,1,24]],"date-time":"2023-01-24T00:00:00Z","timestamp":1674518400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Funds from the project MOREPEP","award":["POCI-01-0247-FEDER-017638"],"award-info":[{"award-number":["POCI-01-0247-FEDER-017638"]}]},{"name":"National Funds from the project MOREPEP","award":["UIDB\/50016\/2020"],"award-info":[{"award-number":["UIDB\/50016\/2020"]}]},{"name":"FCT\u2014Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia through the project","award":["POCI-01-0247-FEDER-017638"],"award-info":[{"award-number":["POCI-01-0247-FEDER-017638"]}]},{"name":"FCT\u2014Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia through the project","award":["UIDB\/50016\/2020"],"award-info":[{"award-number":["UIDB\/50016\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Fish viscera are usually discarded as waste, causing environmental problems, or as low-value by-products. This study describes a self-sufficient and zero waste approach to obtain enzymes and protein hydrolysates from fish by-products. Firstly, recovery steps of viscera enzymatic extract were applied, and the resulting raw extract was stable at a pH range of 8\u20139 and at temperatures between 40 and 50 \u00b0C. The application of the extracted enzymes and alcalase on fish by-products hydrolysis was also determined. The selected conditions for the enzymatic hydrolysis were 10% (E\/S) for 6 h using viscera enzymatic extract and 3% (E\/S) for 2 h using alcalase. Fish protein hydrolysates (FPH) proved to have a notable antioxidant capacity with similar activity, ~11 mg ascorbic acid\/g dry extract (ABTS assay) and ~150 mg Trolox\/g dry extract (ORAC assay). FPH were also able to inhibit the angiotensin-converting enzyme, however, alcalase hydrolysates revealed a higher antihypertensive potential, IC50 of 101 \u00b5g of protein\/mL. In general, FPH obtained by both enzymes systems maintained these bioactivities after the passage throughout a simulated gastrointestinal tract. The hydrolysates also displayed important technological properties, namely oil absorption capacity (~1 g oil\/g sample) and emulsifying property (~40%). Therefore, it will be conceivable to use fish by-products based on a circular economy approach to generate added value compounds for animal and human nutrition.<\/jats:p>","DOI":"10.3390\/molecules28031155","type":"journal-article","created":{"date-parts":[[2023,1,25]],"date-time":"2023-01-25T03:23:49Z","timestamp":1674617029000},"page":"1155","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":52,"title":["Fish By-Products: A Source of Enzymes to Generate Circular Bioactive Hydrolysates"],"prefix":"10.3390","volume":"28","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4665-1098","authenticated-orcid":false,"given":"Sandra","family":"Borges","sequence":"first","affiliation":[{"name":"Universidade Cat\u00f3lica Portuguesa, CBQF\u2014Centro de Biotecnologia e Qu\u00edmica Fina\u2014Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0300-5635","authenticated-orcid":false,"given":"Joana","family":"Odila","sequence":"additional","affiliation":[{"name":"Universidade Cat\u00f3lica Portuguesa, CBQF\u2014Centro de Biotecnologia e Qu\u00edmica Fina\u2014Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal"}]},{"given":"Glenise","family":"Voss","sequence":"additional","affiliation":[{"name":"Universidade Cat\u00f3lica Portuguesa, CBQF\u2014Centro de Biotecnologia e Qu\u00edmica Fina\u2014Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4065-4167","authenticated-orcid":false,"given":"Rui","family":"Martins","sequence":"additional","affiliation":[{"name":"ETSA, Empresa Transformadora de Subprodutos, 2660-119 Loures, Portugal"}]},{"given":"Ana","family":"Rosa","sequence":"additional","affiliation":[{"name":"ETSA, Empresa Transformadora de Subprodutos, 2660-119 Loures, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3156-1412","authenticated-orcid":false,"given":"Jos\u00e9 Ant\u00f3nio","family":"Couto","sequence":"additional","affiliation":[{"name":"Universidade Cat\u00f3lica Portuguesa, CBQF\u2014Centro de Biotecnologia e Qu\u00edmica Fina\u2014Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7765-8060","authenticated-orcid":false,"given":"Andr\u00e9","family":"Almeida","sequence":"additional","affiliation":[{"name":"ETSA, Empresa Transformadora de Subprodutos, 2660-119 Loures, Portugal"}]},{"given":"Manuela","family":"Pintado","sequence":"additional","affiliation":[{"name":"Universidade Cat\u00f3lica Portuguesa, CBQF\u2014Centro de Biotecnologia e Qu\u00edmica Fina\u2014Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,24]]},"reference":[{"key":"ref_1","unstructured":"La Acuicultura, Y. (2016). El Estado Mundial de la Pesca y la Acuicultura, FAO."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/j.cofs.2019.08.001","article-title":"Fermentation in fish and by-products processing: An overview of current research and future prospects","volume":"31","author":"Remize","year":"2020","journal-title":"Curr. Opin. Food Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"160","DOI":"10.1016\/j.foodchem.2016.12.057","article-title":"Fish viscera protein hydrolysates: Production, potential applications and functional and bioactive properties","volume":"224","author":"Villamil","year":"2017","journal-title":"Food Chem."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1016\/j.tifs.2016.02.007","article-title":"Functional and bioactive properties of fish protein hydolysates and peptides: A comprehensive review","volume":"51","author":"Halim","year":"2016","journal-title":"Trends Food Sci. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"364","DOI":"10.1016\/j.ecoenv.2019.01.107","article-title":"Tuna byproducts as a fish-meal in tilapia aquaculture","volume":"172","author":"Kim","year":"2019","journal-title":"Ecotoxicol. Environ. Saf."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1016\/j.jclepro.2013.06.005","article-title":"Trypsins from fish processing waste: Characteristics and biotechnological applications\u2013comprehensive review","volume":"57","author":"Bougatef","year":"2013","journal-title":"J. Clean. Prod."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1016\/j.jff.2017.06.034","article-title":"Health benefits and food applications of bioactive compounds from fish byproducts: A review","volume":"35","author":"Atef","year":"2017","journal-title":"J. Funct. Foods"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"228","DOI":"10.1016\/j.jclepro.2012.11.005","article-title":"Environmental assessment of enzyme use in industrial production\u2014A literature review","volume":"42","author":"Jegannathan","year":"2013","journal-title":"J. Clean. Prod."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"724","DOI":"10.1016\/j.foodchem.2018.08.004","article-title":"An in vitro and in silico study on the antioxidant and cell culture-based study on the chemoprotective activities of fish muscle protein hydrolysates obtained from European seabass and gilthead seabream","volume":"271","author":"Koroleva","year":"2019","journal-title":"Food Chem."},{"key":"ref_10","first-page":"112834","article-title":"Antioxidant and angiotensin I-converting enzyme (ACE) inhibitory peptides of rainbow trout (Oncorhynchus mykiss) viscera hydrolysates subjected to simulated gastrointestinal digestion and intestinal absorption","volume":"154","author":"Zapata","year":"2021","journal-title":"LWT"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"108670","DOI":"10.1016\/j.lwt.2019.108670","article-title":"Bioactive fish hydrolysates resistance to food processing","volume":"117","author":"Guadix","year":"2020","journal-title":"LWT"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"129852","DOI":"10.1016\/j.foodchem.2021.129852","article-title":"Assessment of the biological activity of fish muscle protein hydrolysates using in vitro model systems","volume":"359","author":"Heffernan","year":"2021","journal-title":"Food Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"195","DOI":"10.17221\/593\/2014-CJFS","article-title":"Effect of plant antioxidant and antimicrobial compounds on the shelf-life of seafood\u2014A Review","volume":"33","author":"Pezeshk","year":"2016","journal-title":"Czech J. Food Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.jff.2015.11.007","article-title":"Antioxidant peptides from marine by-products: Isolation, identification and application in food systems","volume":"21","author":"Sila","year":"2016","journal-title":"A review. J. Funct. Foods"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1007\/s13197-015-1998-6","article-title":"Characterisation of hydrolysates prepared from engraved catfish (Nemapteryx caelata) roe by serial hydrolysis","volume":"53","author":"Binsi","year":"2016","journal-title":"J. Food Sci. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"408","DOI":"10.1016\/j.lwt.2019.05.043","article-title":"Bioactivity and bioaccessibility of protein hydrolyzates from industrial byproducts of Stripped weakfish (Cynoscion guatucupa)","volume":"111","author":"Lima","year":"2019","journal-title":"LWT"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"127350","DOI":"10.1016\/j.foodchem.2020.127350","article-title":"Biological and functional properties of peptide fractions obtained from collagen hydrolysate derived from mixed by-products of different fish species","volume":"331","year":"2020","journal-title":"Food Chem."},{"key":"ref_18","first-page":"312","article-title":"Characterization of fish protein hydrolysate from tilapia (Oreochromis niloticus) by-product","volume":"2","author":"Roslan","year":"2014","journal-title":"Agric. Agric. Sci. Procedia"},{"key":"ref_19","first-page":"376","article-title":"Effect of processing methods on nutritional and physico-chemical composition of fish: A review","volume":"6","author":"Abraha","year":"2018","journal-title":"Food Process. Technol."},{"key":"ref_20","first-page":"279","article-title":"Alkaline proteases from digestive tract of four tropical fishes","volume":"6","author":"Alencar","year":"2003","journal-title":"Braz. J. Food Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1016\/j.foodchem.2006.05.050","article-title":"Purification and characterization of trypsin from the viscera of sardine (Sardina pilchardus)","volume":"102","author":"Bougatef","year":"2007","journal-title":"Food Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1016\/j.foodchem.2011.07.015","article-title":"Trypsin from zebra blenny (Salaria basilisca) viscera: Purification, characterisation and potential application as a detergent additive","volume":"130","author":"Ktari","year":"2012","journal-title":"Food Chem."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"893","DOI":"10.1007\/s10695-009-9365-z","article-title":"Trypsin from the viscera of Bogue (Boops boops): Isolation and characterisation","volume":"36","author":"Barkia","year":"2010","journal-title":"Fish Physiol. Biochem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1490","DOI":"10.1016\/j.foodchem.2005.11.040","article-title":"Trypsins from the pyloric ceca of jacopever (Sebastes schlegelii) and elkhorn sculpin (Alcichthys alcicornis): Isolation and characterization","volume":"100","author":"Kishimura","year":"2007","journal-title":"Food Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1016\/j.foodres.2003.12.002","article-title":"Free radical scavenging activity of enzymatic extracts from a brown seaweed Scytosiphon lomentaria by electron spin resonance spectrometry","volume":"37","author":"Ahn","year":"2004","journal-title":"Food Res. Int."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.foodchem.2010.02.013","article-title":"Purification of antioxidative peptides prepared from enzymatic hydrolysates of tuna dark muscle by-product","volume":"122","author":"Hsu","year":"2010","journal-title":"Food Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"366","DOI":"10.1007\/s11356-015-5244-6","article-title":"Valorisation of smooth hound (Mustelus mustelus) waste biomass through recovery of functional, antioxidative and antihypertensive bioactive peptides","volume":"23","author":"Sayari","year":"2016","journal-title":"Environ. Sci. Pollut. Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1735","DOI":"10.1007\/s12649-017-9962-5","article-title":"Valorization of fish viscera for crude proteases production and its use in bioactive protein hydrolysate preparation","volume":"9","author":"Murthy","year":"2018","journal-title":"Waste Biomass Valorization"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"128361","DOI":"10.1016\/j.foodchem.2020.128361","article-title":"Biological activities of the protein hydrolysate obtained from two fishes common in the fisheries bycatch","volume":"342","author":"Camargo","year":"2021","journal-title":"Food Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"3020","DOI":"10.1016\/j.foodchem.2012.06.100","article-title":"Fish protein hydrolysates: Proximate composition, amino acid composition, antioxidant activities and applications: A review","volume":"135","author":"Chalamaiah","year":"2012","journal-title":"Food Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"250","DOI":"10.1016\/j.jff.2018.04.066","article-title":"Acute effect of fish protein hydrolysate supplementation on vascular function in healthy individuals","volume":"46","author":"Alvares","year":"2018","journal-title":"J. Funct. Foods"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1006","DOI":"10.1016\/j.foodchem.2012.09.037","article-title":"Use of viscera extract from hybrid catfish (Clarias macrocephalus \u00d7 Clarias gariepinus) for the production of protein hydrolysate from toothed ponyfish (Gazza minuta) muscle","volume":"136","author":"Klomklao","year":"2013","journal-title":"Food Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"652","DOI":"10.1016\/j.foodchem.2009.10.057","article-title":"Protein hydrolysates from meriga (Cirrhinus mrigala) egg and evaluation of their functional properties","volume":"120","author":"Chalamaiah","year":"2010","journal-title":"Food Chem."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1007\/s00726-011-1190-x","article-title":"Beta-alanine (Carnosyn\u2122) supplementation in elderly subjects (60\u201380 years): Effects on muscle carnosine content and physical capacity","volume":"43","author":"Roschel","year":"2012","journal-title":"Amino Acids"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"600","DOI":"10.1093\/jn\/134.3.600","article-title":"Dietary L-arginine supplementation enhances endothelial nitric oxide synthesis in streptozotocin-induced diabetic rats","volume":"134","author":"Kohli","year":"2004","journal-title":"J. Nutr."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1016\/S0002-9610(02)00823-1","article-title":"Reversal of cancer-related wasting using oral supplementation with a combination of \u03b2-hydroxy-\u03b2-methylbutyrate, arginine, and glutamine","volume":"183","author":"May","year":"2002","journal-title":"Am. J. Surg."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"20594","DOI":"10.1038\/srep20594","article-title":"Branched-chain and aromatic amino acid profiles and diabetes risk in Chinese populations","volume":"6","author":"Chen","year":"2016","journal-title":"Sci. Rep."},{"key":"ref_38","first-page":"6","article-title":"Metal ion-binding properties of L-glutamic acid and L-aspartic acid, a comparative investigation","volume":"2","author":"Sajadi","year":"2010","journal-title":"Nat. Sci."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1111\/j.1541-4337.2006.tb00081.x","article-title":"Low-calorie Sweeteners and Other Sugar Substitutes: A Review of the Safety Issues","volume":"5","author":"Kroger","year":"2006","journal-title":"Compr. Rev. Food Sci. Food Saf."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"535","DOI":"10.1007\/s13197-018-3549-4","article-title":"Bioactive food derived peptides: A review on correlation between structure of bioactive peptides and their functional properties","volume":"56","author":"Karami","year":"2019","journal-title":"J. Food Sci. Technol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.jff.2017.04.013","article-title":"Bioactive peptides from shrimp shell processing discards: Antioxidant and biological activities","volume":"34","author":"Ambigaipalan","year":"2017","journal-title":"J. Funct. Foods"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1231","DOI":"10.1016\/S0891-5849(98)00315-3","article-title":"Antioxidant activity applying an improved ABTS radical cation decolorization assay","volume":"26","author":"Re","year":"1999","journal-title":"Free Radic. Biol. Med."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"3539","DOI":"10.1039\/D0FO00188K","article-title":"Enzymatic hydrolysis of insect Alphitobius diaperinus towards the development of bioactive peptide hydrolysates","volume":"11","author":"Sousa","year":"2020","journal-title":"Food Funct."},{"key":"ref_44","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_45","doi-asserted-by":"crossref","first-page":"410","DOI":"10.1021\/jf072277p","article-title":"Investigations into inhibitor type and mode, simulated gastrointestinal digestion, and cell transport of the angiotensin I-converting enzyme\u2013inhibitory peptides in Pacific hake (Merluccius productus) fillet hydrolysate","volume":"56","author":"Hu","year":"2008","journal-title":"J. Agric. Food Chem."},{"key":"ref_46","first-page":"150","article-title":"Physicochemical properties of cross linked acha (digitaria exilis) starch with citric acid","volume":"3","author":"Isah","year":"2017","journal-title":"Chem. Int"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"98","DOI":"10.1590\/S0101-20612012005000007","article-title":"Physicochemical characteristics and functional properties of vitabosa (mucuna deeringiana) and soybean (glycine max)","volume":"32","year":"2012","journal-title":"Food Sci. Technol."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"21","DOI":"10.3923\/ijbc.2011.21.36","article-title":"Chemical and physicochemical properties of tilapia (Oreochromis niloticus) fish protein hydrolysate and concentrate","volume":"5","author":"Foh","year":"2011","journal-title":"Int. J. Biol. Chem."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"109003","DOI":"10.1016\/j.lwt.2019.109003","article-title":"Effects of pressure-assisted enzymatic hydrolysis on functional and bioactive properties of tilapia (Oreochromis niloticus) by-product protein hydrolysates","volume":"122","author":"Hemker","year":"2020","journal-title":"LWT"},{"key":"ref_50","unstructured":"AOAC (1995). Official Methods of Analysis, Association of Official Analytical Chemists. [16th ed.]."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1218","DOI":"10.1016\/j.foodchem.2007.06.048","article-title":"Determination of biogenic amines in wines by HPLC with precolumn dansylation and fluorimetric detection","volume":"106","author":"Proestos","year":"2008","journal-title":"Food Chem."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"4619","DOI":"10.1021\/jf010586o","article-title":"Development and validation of an improved oxygen radical absorbance capacity assay using fluorescein as the fluorescent probe","volume":"49","author":"Ou","year":"2001","journal-title":"J. Agric. Food Chem."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.idairyj.2005.12.011","article-title":"Identification of novel antihypertensive peptides in milk fermented with Enterococcus faecalis","volume":"17","author":"Ramos","year":"2007","journal-title":"Int. Dairy J."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.lwt.2019.05.011","article-title":"Valorization of spent brewer\u2019s yeast: Optimization of hydrolysis process towards the generation of stable ACE-inhibitory peptides","volume":"111","author":"Amorim","year":"2019","journal-title":"LWT"}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/28\/3\/1155\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:14:39Z","timestamp":1760120079000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/28\/3\/1155"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,1,24]]},"references-count":54,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2023,2]]}},"alternative-id":["molecules28031155"],"URL":"https:\/\/doi.org\/10.3390\/molecules28031155","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,1,24]]}}}