Mikrovalna ekstrakcija polifenolnih spojeva iz kožice grožđa

master's thesis

• Title (english): Microwave extraction of polyphenolic compounds from grape skin
• Author: Marija Gavranić
• Mentor: Danijela Ašperger (mentor)
• Committee member: Danijela Ašperger (predsjednik povjerenstva)
• Committee member: Marijana Hranjec (član povjerenstva)
• Committee member: Jasminka Karoglan-Kontić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2015-09-22, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry; Analytic Chemistry

Abstract

Polifenolni spojevi su sekundarni metaboliti sadržani u biljkama. Obuhvaćaju veliki broj spojeva koji imaju aromatske prstenove s jednom ili više hidroksilnih skupina. Polifenoli imaju učinak na ljudsko zdravlje: antibakterijsko, protuupalno, antioksidativno i antikancerogeno. Biološke funkcije polifenola pripisuju se njihovoj izvanrednoj antioksidacijskoj i antiradikalskoj aktivnosti. Bobica grožđa predstavlja osnovno mjesto gdje se odvija biosinteza sekundarnih metabolita koji su od velike važnosti za kakvoću vina. Kod grožđa, izuzevši fenolne spojeve sjemenke, najveći udio fenolnih spojeva se nalazi u kožici bobice. Predmet našeg istraživanja su bili polifenoli: antocijani, flavonoli i flavan-3-oli u kožici grožđa sorte Regent. Polifenoli iz kožice grožđa ekstrahirani su ekstrakcijom potpomognutom mikrovalovima. Dobiveni ekstrakti analizirani su tekućinskom kromatografijom visoke djelotvornosti uz primjenu detektora s nizom fotodioda (DAD), fluorescencijskim detektorom (FLD). Za analizu je korištena kolona Luna Phenyl-Hexyl Phenomenex, USA). Dimenzije kolone su 250 mm x 4,6 mm, a veličina zrnaca je 5 μm, sa predkolonom Phenyl (4.0*3.0). Pokretna faza se sastojala od: A voda/fosforna kiselina (99,5/0,5/v/v) i B acetonitril/voda/fosforna kiselina (50/49,5/0,5/v/v/v). Cilj ovog istraživanja bio je iz kožice grožđa sorte Regent ekstrahirati polifenolne spojeve i optimizirati metodu ekstrakcije. Provedene analize pokazale su da mikrovalovima potpomognuta ekstrakcija je vrlo učinkoviti način ekstrakcije antocijana s 50 % etanola pri T = 40 °C za t = 10 minuta; flavonola s 60 % acetonitrila pri T= 40 °C za t = 30 minuta; te flavan-3-ola s 20 % acetonitrila pri T=60 °C za t= 5 minuta. Za postupak optimizacije svih skupina spojeva ekstrakcija se provodi s 60 % EtOH, pri T= 40 °C za t = 5 minuta. RSD vrijednosti novooptimizirane metode su vrlo niske (< 2 % za antocijane i flavonole, te oko 9 % za flavan-3-ole), te se može zaključiti da je metoda precizna i točna. Ovo znanstveno istraživanje može se koristiti za bolju iskoristivost grožđa kao sirovine za dobivanje flavonoida u komercijalne svrhe.

Abstract (english)

Polyphenol compounds are secondary metabolites contained in plants. Comprise a large number of compounds having aromatic rings with one or more hydroxyl groups. Polyphenols have an effect on human health: antibacterial, anti-inflammatory, antioxidant, anti-cancer. The biological function of polyphenols attributed to their excellent antioxidant and antiradical activities. Grapes, the main place where takes place the biosynthesis of secondary metabolites that are of great importance for the quality of wine. In grapes, except phenolic compounds seeds, the largest share of phenolic compounds is in the skin of the berries. The subjects of our research were polyphenols: anthocyanins, flavonols, and flavan-3-ol in the skin of grapes Regent. Polyphenols from grape skins, we extracted microwave-assisted extraction. The obtained extracts were analysed by high performance liquid chromatography with a photodiode array detector (DAD) and fluorescence detector (FLD). For chromatographic separation was used column Luna Phenyl-Hexyl Phenomenex, USA). Column dimensions were 250 mm x 4.6 mm and the grain size is 5 microns, with a Phenyl precolumn (4.0 * 3.0). The mobile phase consisted of: A water / phosphoric acid (99,5 / 0,5 / v / v) and B is acetonitrile / water / phosphoric acid (50 / 49,5 / 0,5 / v / v / v). The aim of this study was extract polyphenolic compounds from the skins of grapes varieties Regent and optimize the microwave extraction method. Analyses show that microwave assisted extraction is a very effective methods of extracting anthocyanins from 50 % ethanol at T = 40 °C to t = 10 minutes; flavonols with 60 % acetonitrile at T = 40 °C for t = 30 min; flavan-3-ol with 20 % acetonitrile at T = 60 °C for t = 5 minutes. In the process of optimization of the extraction of compounds is performed with 60 % EtOH at T = 40 °C for t = 5 minutes. RSD values newoptimized methods are very low (< 2 % of flavonols and anthocyanins, and about 9 % of flavan-3-ole), which indicates that the method is accurate and precise. This scientific research can be used for better use grapes as a basis for obtaining the flavonoids for commercial purposes.

• Keywords: grožđe; polifenoli; mikrovalna ekstrakcija; tekućinska kromatografija visoke djelotvornosti
• Keywords (english): grapes; polyphenols; microwave extraction; high performance liquid chromatography
• Language: croatian
• URN:NBN: urn:nbn:hr:149:393356
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Applied organic chemistry; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra primijenjene kemije (magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-03-06 13:42:11