Određivanje hidroksilnih radikala i antioksidacijskog kapaciteta elektronskom spinskom rezonancijom nakon visokonaponskog pražnjenja

master's thesis

• Title (english): Determination of hydroxyl radicals and antioxidant capacity using electron spin resonance after high voltage electrical discharge
• Author: Danijela Šeremet
• Mentor: Anet Režek Jambrak (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Food Processes Engineering); Zagreb
• Defense date and country: 2018-07-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Visokonaponsko pražnjenje pripada u tehnike netermalnog procesiranja hrane. U ovome radu korišten je hibridni reaktor s argonom kao radnim plinom. Tretman se provodio na destiliranoj vodi i soku od jabuke kod različitih frekvencija (60, 90 i 120 Hz) kroz različito vrijeme (3, 5 i 10 min). Elektronska spinska rezonancija korištena je u svrhu određivanja hidroksilnih radikala i antioksidacijskog kapaciteta. Tretman kod 120 Hz kroz 10 min rezultirao je nastankom najvećeg broja hidroksilnih radikala u uzorcima destilirane vode, dok kod uzoraka soka oni nisu zabilježeni. Primjenom blisko-infracrvene spektroskopije uočene su strukturne promjene i kod uzoraka vode i soka. Najveći porast antioksidacijskog kapaciteta soka od jabuke zabilježen je nakon tretmana na frekvenciji od 60 Hz kroz 10 min. Za uzorke soka provedena je analiza parametara boje po CIE L*a*b* sistemu boja te su najveće promjene boje određene nakon tretmana na frekvenciji od 120 Hz kroz 10 min.

Abstract (english)

Highvoltage electrical discharge is non-thermal food processing technique. In this research, experiments were conducted in hybrid reactor with argon as working gas. Treated materials were distilled water and apple juice. Plasma processing parameters were frequency (60, 90 and 120 Hz) and treatment time (3, 5 and 10 min). Electron spin resonance was used to determine hydroxyl radicals and antioxidant capacity. 10 min treatment at 120 Hz resulted in the biggest number of formed hydroxyl radicals in distilled water samples, while they were not determined in apple juice samples. Changes in structural composition were determined both in water and juice samples using near-infrared spectroscopy. The highest increase in antioxidant capacity of apple juice was observed after 10 min treatment at 60 Hz. Analysis of color parameters for apple juice was performed using CIE L*a*b* color system. The biggest change in values of color parameters were observed after 10 min treatment at 120 Hz.

• Keywords: visokonaponsko pražnjenje; elektronska spinska rezonancija; bliska-infracrvena spektroskopija; antioksidacijski kapacitet; hidroksilni radikali
• Keywords (english): highvoltage electrical discharge; electron spin resonance; near-infrared spectroscopy; antioxidative capacity; hydroxyl radicals
• Language: croatian
• URN:NBN: urn:nbn:hr:159:170123
• 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: 2019-11-26 13:40:38