Frakcioniranje polifenolnih spojeva – razvoj metodologije i primjena na mahuni graška

master's thesis

• Title (english): Fractionation of polyphenol compounds methodology development and application on pea pod
• Author: Jelena Kralj
• 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: 2020-09-25, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Agro-industrijski otpad sadrţi brojne vrijedne sastojke koji se mogu iskoristiti u razvoju i proizvodnji novih proizvoda dodane vrijednosti. U prehrambenoj industriji su meĎu najzanimljivijima polifenolni spojevi zbog poznatih pozitivnih učinaka na zdravlje. Cilj ovoga rada bio je definirati postupak frakcijskog izdvajanja polifenolnih spojeva te ga primijeniti za odreĎivanje polifenolnih spojeva u mahuni graška. U postupku frakcioniranja polifenolni spojevi su izdvojeni kao frakcije slobodnih, konjugiranih – esterificiranih i glikoziliranih te vezanih spojeva primjenom, redoslijedno, ekstrakcije tekuće-tekuće, alkalne i kiselinske hidrolize izvornog ekstrakta te alkalne hidrolize ostatka nakon početne ekstrakcije. Analiza polifenolnih spojeva provedena je HPLC-DAD metodom, razvijenom za analizu 21 spoja iz različitih polifenolnih podskupina. Dodatak natrijevog klorida u koraku ekstrakcije tekuće-tekuće, a zatim i etilendiaminotetraoctene kiseline i askorbinske kiseline u koraku alkalne hidrolize, značajno su povećali stabilnost i ekstrakcijsko iskorištenje polifenolnih spojeva. U uvjetima frakcioniranja, modelne molekule esterificiranih i glikoziliranih polifenola bile su uspješno hidrolizirane, uz relativno zadovoljavajuće iskorištenje osloboĎenih spojeva. Polifenoli u mahuni graška prisutni su uglavnom u konjugiranom obliku, kao esteri p-kumarinske i sinapinske kiseline, te kao glikozidi kvercetina, s udjelima, redoslijedno, 207, 158 i 103 μg gs.tv.ˉ¹, dok su slobodni i vezani spojevi vrlo malo zastupljeni. Udio ukupnih polifenola u koncentriranom izvornom ekstraktu mahune graška iznosio je 4,77 mgGAE gs.tv.ˉ¹ (Folin-Ciocalteu), a prateći antioksidacijski kapacitet 12,91 μmolTrolox gs.tv.ˉ¹ (DPPH). Mahuna graška moţe se smatrati relativno dobrim izvorom polifenola, čiju djelomičnu identifikaciju je uvelike olakšala primjena razvijenog postupka frakcioniranja.

Abstract (english)

Agro-industrial wastes contain a number of valuable ingredients that can be re-used in the development and production of new added-value products. Among them, polyphenols are particularly interest compounds because of their known health-beneficial properties. The aim of this work was to define the procedure for fractionation of polyphenols and further to apply it for determination of polyphenols form pea pod. During fractionation, the polyphenols were isolated as fractions of free, conjugated – esterified and glycosylated, as well as bound compounds following liquid-liquid extraction, alkaline and acidic hydrolysis of the initial extract and alkaline hydrolysis of the residue after the initial extraction, respectively. The analysis of polyphenols was performed using HPLC-DAD method, specially developed to analyse 21 individual compounds from different polyphenolic subgroups. The addition of sodium chloride during liquid-liquid extraction, and further of ethyendiaminotetraacetic and ascorbic acid during alkaline hydrolysis, have markedly contributed to the stability and recovery of polyphenolic compounds. With the defined fractionation conditions, the model molecules of esterified and glycosylated polyphenols were successfiully hydrolysed, accompanied by relatively sufficient recovery of liberated compounds. Polyphenols in pea pod were mainly found as conjugates, as esters ofp-coumaric and sinapic acids, as well as quercetin glycosides, with contents of 207, 158 i 103 μg gdw.ˉ¹, respectively, while free and boundphenolics were minorly represented. Total phenolic content of concentrated initial pea pod extract exhibited 4.77 mgGAE gdwˉ¹ (Folin-Ciocalteu), accompanied by antioxidant capacity of 12.91 μmolTrolox gdw.ˉ¹ (DPPH). Pea pod can be established as relatively good source of polyphenols, the partial identification of which was largely enabled by the developed polyphenol fractionation procedure.

• Keywords: agro-industrijski otpad; frakcioniranje; hidroliza; mahuna graška; polifenoli
• Keywords (english): agro-industrial waste; fractionation; hydrolysis; pea pod; polyphenols
• Language: croatian
• URN:NBN: urn:nbn:hr:159:021292
• 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: 2021-01-21 12:52:19