Karakterizacija i inkapsulacija polifenolnog ekstrakta i pektina ljuske crvenog luka

master's thesis

• Title (english): Characterization and encapsulation of polyphenol extract and pectin from onion peel
• Author: Marija Soldo
• Mentor: Draženka Komes (mentor)
• 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: 2019-01-23, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Cilj ovog rada bio je ispitati potencijal ljuske crvenog luka kao izvora polifenolnih spojeva (kvercetina) i pektina. Primjenom konvencionalne i ultrazvučne metode pripremljeni su polifenolni ekstrakti ljuske crvenog luka koji su zatim inkapsulirani u sustave nosača alginata i pektina pripremljene u različitim omjerima (A, AP_80:20, AP_70:30 i AP_60:40). Inkapsulacija je provedena metodom ionskog geliranja. Pektin korišten u sustavu nosača također je dobiven ekstrakcijom iz ljuske crvenog luka. Karakterizacija polifenolnog ekstrakta provedena je određivanjem udjela ukupnih polifenola, antioksidacijskog kapaciteta i udjela pojedinačnih polifenola promjenom HPLC metode. Ekstrahiranom pektinu određena je molarna masa, stupanj esterifikacije, udio galakturonske kiseline te pH vrijednost. Formiranim hidrogel česticama određena su fizikalno-kemijska svojstava, inkapsulacijska učinkovitost te kinetika otpuštanja ukupnih polifenola i antioksidacijskog kapaciteta u simuliranim gastrointestinalnim uvjetima. Ultrazvučna metoda rezultirala je većim udjelom polifenola među kojima dominiraju kvercetin i njegovi derivati. Ekstrahirani pektin je visokometilirajući te je u svrhu dobivanja stabilnih inkapsulacijskih sustava miješan s alginatom. Binarni alginatno-pektinski sustavi rezultirali su hidrogel česticama najboljih bioaktivnih i mehaničkih svojstava.

Abstract (english)

The aim of this study was to investigate the potential of the onion peel as a source of polyphenol compounds (quercetin) and pectin. Polyphenolic onion peel extracts were prepared by conventional and ultrasonic methods and then encapsulated in alginate and pectin carrier systems prepared at different concentrations (A, AP_80: 20, AP_70: 30 and AP_60: 40). Encapsulation was carried out using method of ionic gelation. Used pectin was also extracted from onion peel. The characterization of the polyphenolic extract was performed by determining the content of total polyphenols, antioxidant capacity and the content of individual polyphenols by HPLC method. Extracted pectin was characterized by molar mass, degree of esterification, the content of galacturonic acid and pH value. Formed hydrogel particles were tested for physico-chemical characteristics, encapsulation efficiency and release kinetics of total polyphenols and antioxidant capacity in simulated gastrointestinal conditions. Ultrasonic method resulted in a higher content of polyphenols, dominated by quercetin and quercetin derivatives. The extracted pectin was high metoxyl and in order to obtain more stable encapsulation systems it was mixed with alginate. Binary alginate-pectin systems resulted in hydrogel particles with the best bioactive and mechanical properties.

• Keywords: ionsko geliranje; ljuska crvenog luka; kvercetin; pektin; polifenoli
• Keywords (english): ionic gelation; onion peel; quercetin; pectin; polyphenols
• Language: croatian
• URN:NBN: urn:nbn:hr:159:209368
• Study programme: Title: Nutrition; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra nutricionizma (magistar/magistra nutricionizma)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-12-06 13:50:45