Stabilnost fenolnih spojeva sokova šipka tretiranih netoplinskim tehnikama

master's thesis

• Title (english): The effect of non-thermal technologies on the stability of polyphenolics in pomegranate juice
• Author: Željka Kresoja
• Mentor: Danijela Bursać Kovačević (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Technology of Fruits and Vegetables Preservation and Processing); Zagreb
• Defense date and country: 2017-07-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Cilj ovog istraživanja bio je ispitati stabilnost ukupnih fenola i monomernih antocijana mutnih sokova od šipka tretiranih netoplinskim tehnikama te rezultate usporediti sa svježim i pasteriziranim sokovima tijekom 7 dana skladštenja na 4 °C. Sokovi od šipka tretirani su: (i) ultrazvukom uz variranje amplitude (75 i 100 %) i vremena tretiranja (2,5 i 5 min) te (ii) hladnom plazmom uz variranje frekvencije (60 i 90 Hz) i vremena tretiranja (2,5 i 5 min), kao i u kombinaciji svih ovih parametara prema punom faktorskom planu pokusa. Pasterizacija je provedena pri 90 °C/1 min. Ukupni fenoli i antocijani određeni su spektrofotometrijski. Za razliku od monomernih antocijana, pasterizacija nije značajno utjecala na stabilnost ukupnih fenola, dok su netermalne tehnike utjecale na značajno smanjenje udjela ukupnih fenola i monomernih antocijana u odnosu na pasterizirani i netretirani sok. Kombinirani tretman ultrazvuka i hladne plazme kao i tretman hladnom plazmom zasebno značajno je povoljnije djelovao na stabilnost ukupnih fenola u usporedbi sa ultrazvukom, dok su na stabilnost monomernih antocijana sve netoplinske tehnike zasebno i u kombinaciji jednako djelovale.

Abstract (english)

The aim of this study was to evaluate the effect of non-thermal technologies on the stability of total phenols and monomeric anthocyanins in pomegranate juices and to compare results with pasteurized and non-treated juices during 7 days storage at 4 °C. Pomegranate juices were treated with ultrasound and cold plasma, separately and then in combination of both treatments. Experiment was designed to investigate the effect of ultrasound operating conditions (75 and 100 %; treatment time 2,5 and 5 min) and plasma operating conditions (60 and 90 Hz; treatment time 2,5 and 5 min) alone and in combination according to full factorial design. Pomegranate juices were pasteurized at 90 °C/1 min. Total phenolic content and monomeric anthocyanins content were spectrofotometrically determined. Obtained results revealed that pasteurization did not significantly influenced stability of total phenols, while stability of monomeric anthocyanins were lower in pasteurized than in non-treated juices. Furthermore, when applied alone, non-thermal technologies significantly reduced concentration of total phenols and monomeric anthocyanins in compare to pasteurized and non-treated juice.Ultrasound and cold plasma treatemnts in combinations, as well as cold plasma treatment alone, exhibited greater stability of total phenols in comparison to ultrasound treatment alone. With respect to monomeric anthocyanins stability, all non-thermal technologies, alone or in combination, significantly reduced monomeric anthocyanins stability.

• Keywords: sok od šipka; monomerni antocijani; ukupni fenoli; ultrazvuk; hladna plazma
• Keywords (english): pomegranate juice; monomeric anthocyans; total phenols; ultrasound; cold plasma
• Language: croatian
• URN:NBN: urn:nbn:hr:159:606141
• Study programme: Title: Food Safety Management; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka upravljanja sigurnošću hrane (magistar/magistra inženjer/inženjerka upravljanja sigurnošću hrane)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-11-06 13:43:32