Utjecaj uvjeta ekstrakcije i hidrolize na izdvajanje kvercetina iz ljuske luka i mahune graška

master's thesis

• Title (english): The impact of extraction and hydrolysis conditions on the recovery of quercetin from onion peel and pea pod
• Author: Ivana Dajčić
• Mentor: Draženka Komes (mentor)
• Committee member: Ksenija Marković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Chemistry and Technology of Carbohydrates and Confectionery Products); Zagreb
• Defense date and country: 2021-03-08, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Iskorištavanje agro-industrijskog otpada kao izvora vrijednih bioaktivnih sastojaka, u novije vrijeme dobiva sve veću važnost, zbog svog bogatog kemijskog sastava i velike dostupne količine. Ljuska luka i mahuna graška čine značajan udjel otpada koji nastaje prilikom proizvodnje i primarne prerade luka i graška. Nastojeći iskoristi ove sekundarne biljne sirovine za izdvajanje bioaktivnih spojeva, cilj ovog rada bio je odrediti utjecaj različitih uvjeta ekstrakcije i hidrolize na izdvajanje kvercetina. Primijenjene su tri konvencionalne metode ekstrakcije (maceracija, infuzija i dekokcija) te dvije inovativne (ultrazvuk i mikrovalovi). Dekokcija je rezultirala najvišim prinosima ukupnih polifenola iz oba uzorka. Inovativne metode također su pokazale visoku ekstrakcijsku učinkovitost. HPLC analizom je kvalitativno i kvantitativno određen polifenolni sastav ljuske luka (protokatehinska kiselina, kvercetin-3,4'-diglukozid, kvercetin-3-glukozid, kvercetin-4'-glukozid, kvercetin) i djelomični sastav mahune graška nakon hidrolize (p-kumarinska kiselina, sinapinska kiselina, kvercetin). Kombinacijom ekstrakcije i hidrolize u optimiranim uvjetima, iz ljuske luka izdvojena je protokatehinska kiselina (4,25 mg g-1) i kvercetin aglikon (9,86 mg g-1). U mahuni graška kvercetin je prisutan u značajno manjem udjelu nego u ljusci luka, i to isključivo u konjugiranom obliku. Ljuska luka može se smatrati vrlo bogatim izvorom kvercetina i protokatehinske kiselina, dok mahuna graška relativno dobrim izvorom kvercetina te je nužno provesti dodatna istraživanja kako bi se polifenolni sastav mahune graška u potpunosti definirao.

Abstract (english)

The exploatation od agro-industrial wastes as a source of bioactive ingredients, is gaining a significant importance in reecnt years, because ot its rich chemical composition and large available quantity. Onion peel and pea pod make a significant part of waste generated during produsctin and primary processing of onions and peas. In the effort to make the most of these secondary plant waste materials by means of bioactive compounds isolation, the aim of this study was to determine the influence of different extraction and hydrolysis conditions on the extraction of quercetin. Three conventional extraction methods (maceration, infusion and decoction) and two innovative techniques (ultrasound and microwaves) were evaluated. Extraction by decocteion resulted with the highest content of total polyphenols from both samples. Innovative techniques as well have shown a high extraction efficiency. HPLC analysis was used to qualitatively and quantitatively determine the polyphenolic composition of onion peel (protocatechuic acid, quercetin-3,4'-diglucoside, quercetin-3-glucoside, quercetin-4'-glucoside, quercetin) and the partial composition of pea pods upon hydrolysis (p-coumaric acid, synapic acid, quercetin). Using the combined extraction and hydrolysis at optimised conditions, protocatechuic acid (4.25 mg g-1) and quercetin aglycone (9.86 mg g-1) were extracted from onion peel. In pea pod, quercetin aglycone is present in significantly smaller amount, exclusivelly in conjugated form. Onion peel can be considered an excellent source of quercetin, while pea pod a relatively good source of quercetin, although further research in necessary to fully determine the polyphenolic composition of the pea pod.

• Keywords: ekstrakcija; hidroliza; kvercetin; ljuska luka; mahuna graška
• Keywords (english): extraction; hydrolysis; quercetin; onion peel; pea pod
• Language: croatian
• URN:NBN: urn:nbn:hr:159:821318
• Study programme: Title: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-03-17 11:42:40