Title UTJECAJ SEZONE RASTA NA KEMIJSKI SASTAV I BIOLOŠKI POTENCIJAL ODABRANIH VRSTA SMEĐIH ALGI IZ JADRANSKOG MORA Title (english) The EFFECT OF THE gROWING SEASONS ON CHEMICAL COMPOSITION AND BIOLOGICAL POTENTIAL OF SELECTED BROWN SEA WEEDS FROM THE ADRIATIC Author Martina Čagalj Mentor Vida Šimat (mentor)Mentor Danijela Skroza (komentor)Committee member Mirela Petrić (predsjednik povjerenstva)Committee member Ivana Generalić Mekinić (član povjerenstva)Committee member Željka Trumbić (član povjerenstva)Granter University of Split Defense date and country 2023-05-08, Croatia Scientific / art field, BIOTECHNICAL SCIENCES Universal decimal classificationUDC ) 502/504 - Environmental science. Conservation of natural resources. Threats to the environment and protection against them Abstract Smeđe alge su rasprostranjen, nedovoljno istražen i iskorišten te ekonomski vrijedan prirodni resurs. Prepoznate su kao izvor različitih skupina spojeva s dokazanim biološkim aktivnostima (antibakterijska, antioksidacijska, antiviralna, antitumorna, citotoksična aktivnost, itd.). Kemijski sastav algi ovisi o brojnim ekološkim čimbenicima koji variraju tijekom sezone rasta, o uvjetima predobrade algalnog materijala kao i različitim parametrima ekstrakcijskog procesa. U ovom istraživanju optimizirane su metode sušenja i odabrani uvjeti zelenih postupaka za ekstrakciju bioaktivnih tvari iz alge Padina pavonica s ciljem povećanja prinosa fenolnih spojeva, a time i njihove antioksidacijske aktivnosti. Metoda liofilizacije je odabrana kao najbolja metoda sušenja dok su se ekstrakcije potpomognute mikrovalovima i ultrazvukom pokazale učinkovitijima za dobivanje ekstrakata snažne biološke aktivnosti s višim sadržajem fenolnih spojeva. Po prvi put, izolirani ekstrakt P. pavonica korišten je za razvoj bioaktivnog premaza za filmove od polilaktične kiseline čime je potvrđen potencijal primjene ove alge u ambalažnim materijalima koji se koriste u prehrambenoj industriji. Kemijski sastav i biološka aktivnost algi Cystoseira compressa i P. pavonica pokazali su varijabilnost kroz sezonu rasta. Najviši sadržaj ukupnih fenolnih spojeva i najsnažnija antioksidacijska aktivnost zabilježeni su kod uzoraka branih u lipnju, a najveća antimikrobna aktivnost dokazana je za one brane u lipnju, srpnju i kolovozu, kada su izmjerene najviše temperature mora. Kemijski profil eteričnog ulja alge C. compressa mijenjao se sa sezonom rasta. Najviši udio masnih kiselina zabilježen je u svibnju i lipnju, dok je u srpnju i kolovozu zabilježen najviši udio alkohola. Istražen je i utjecaj postupka sušenja i sezone rasta na sastav hlapljivih organskih spojeva alge Halopteris scoparia. Uzorci svježih algi su se značajnije razlikovali kroz mjesece uzorkovanja u odnosu na uzorke suhih algi. U uzorcima vršnih para su dominantne skupine spojeva svježih i suhih algi bili alifatski spojevi i derivati benzena dok su u hidrodestilatima svježih algi najzastupljeniji bili alifatski spojevi u svibnju i rujnu te terpeni u lipnju, srpnju i kolovozu. Temeljem navedenog, rezultati ovih istraživanja ukazuju na činjenicu da su smeđe alge Jadranskog mora izvor bioaktivnih spojeva s potencijalnom primjenom u prehrambenoj i farmaceutskoj industriji.
Abstract (english) Brown seaweeds are abundant, underexplored, underused and economically valuable natural resource. They are recognized as a source of various compounds with proven biological activity (antibacterial, antioxidant, antiviral, antitumor, cytotoxic activity, etc.). The chemical composition of seaweeds depends on a number of environmental factors that vary during the seasonal growth, on the pre-treatment of algal material and on the extraction parameters. In this study, the drying methods and the selected conditions of the green procedures for the extraction of bioactives from Padina pavonica were optimized with the aim of increasing the yield of phenolic compounds and its antioxidant activity. Freeze-drying was chosen as the best drying method, and extractions assisted by microwaves and ultrasound were found to be the most suitable to obtain extracts with strong biological activity and higher total phenolic content. For the first time, P. pavonica extract was used to develop a bioactive coating for polylactic acid films, confirming the potential of this seaweed for the use in packaging materials for food industry. The chemical composition and biological activity of Cystoseira compressa and P. pavonica showed variations throughout the growing season. The highest content of total phenolic compounds and the strongest antioxidant activity were found in June samples, and the highest antimicrobial activity in June, July and August samples, when the highest sea temperatures were recorded. The chemical profile of the C. compressa essential oil changed during seasonal growth. The highest percentage of fatty acids was recorded in May and June, while the highest percentage of alcohol was recorded in July and August. The influence of drying procedures and growing season on the composition of Halopteris scoparia volatile organic compounds was investigated. Fresh seaweed samples differed more significantly between sampling months than dry seaweed samples. In the headspace samples, the predominant groups of compounds of fresh and dry samples were aliphatic compounds and benzene derivatives, while in the hydrolats of fresh samples, aliphatic compounds were most represented in May and September and terpenes in June, July, and August. Brown seaweeds of the Adriatic Sea are a potential source of bioactive compounds that can be used in the food and pharmaceutical industries
Keywords
antioksidacijska aktivnost
antimikrobna aktivnost
smeđe alge
razvoj novog pakiranja
zelena ekstrakcija
Keywords (english)
antioxidant activity
antimicrobial activity
brown seaweeds
new packaging development
green extraction
Language croatian URN:NBN urn:nbn:hr:226:806979 Promotion 2023-06-05 Study programme Title: Obtaining a doctorate of science outside of doctoral studies Type of resource Text File origin Born digital Access conditions Open access Terms of use Created on 2024-04-08 12:25:28
