Utjecaj ultrazvučne obrade na bioaktivne sastojke soka višnje Maraske

doctoral thesis

• Title (english): Influence of ultrasound processing on bioactive compounds of Marasca sour cherry juice
• Author: Marija Badanjak Sabolović
• Mentor: Vesna Lelas (mentor)
• Committee member: Verica Dragović-Uzelac (predsjednik povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; Zagreb
• Defense date and country: 2014-02-14, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology
• Universal decimal classification (UDC): 633/635 - Horticulture. Fruit growing. Viticulture. Gardening

Abstract

Svrha istraživanja provedenih u okviru ovog doktorskog rada bila je ispitati mogućnost primjene ultrazvuka kao zamjene za uobičajenu toplinsku obradu koja se primjenjuje u procesima proizvodnje voćnih sokova, a sa ciljem očuvanja prirodno prisutnih bioaktivnih spojeva i njihove antioksidacijske aktivnosti. Istraživanja su provedena sa sokom višnje Maraske (Prunus cerasus L.) koji je obrađivan toplinski te primjenom ultrazvuka visokog intenziteta i niske frekvencije (20 kHz). Primijenjene su dvije ultrazvučne sonde različitih promjera (12,7mm i 19,1mm). Tretiranje je vršeno s amplitudama ultrazvuka 50%, 75% i 100% pri temperaturama 20°C, 35°C i 50°C u trajanju od 3, 6 i 9 minuta. Toplinska obrada soka provedena je u cijevnom izmjenjivaču topline pri temperaturi 80°C u trajanju 2 minute. Učinak toplinskog i ultrazvučnog tretiranja na sok višnje praćen je određivanjem promjena na boji te udjela ukupnih i pojedinih fenolnih spojeva i antocijana, uz istovremeno određivanje njihove antioksidacijske aktivnosti (DPPH, ABTS metoda). Rezultati su pokazali da bi se ultrazvuk u određenim uvjetima mogao uspješno primijeniti u procesima proizvodnje sokova višnje Maraske.

Abstract (english)

The objective of the present thesis was to investigate the feasibility of ultrasound treatment as an alternative to conventional thermal treatments in fruit juice production in order to preserve the naturally occurring bioactive compounds and their antioxidant activity. Marasca sour cherry juice has been thermally processed and treated with high intensity and low frequency (20 kHz) ultrasound. Two ultrasound probes with different diameters were used (12,7 mm and 19,1 mm). Treatments using ultrasound amplitudes 50%, 75% and 100% at temperatures of 20°C, 35°C and 50°C for 3, 6, and 9 minutes were carried out. Thermal processing of juice was conducted in a tubular heat exchanger at temperature of 80°C in the period of 2 minutes. The effect of thermal and high intensity ultrasound processing on sour cherry juice quality was monitored measuring color difference, content of total polyphenols and anthocyanins as well as polyphenols composition. Simultaneously, their antioxidant activity was determined (DPPH, ABTS assay). Results showed that ultrasound, in specific processing conditions, could be successfully applied in Marasca sour cherry juice production processes.

• Keywords: ultrazvuk visokog intenziteta; sok višnje; bioaktivni sastojci; antioksidacijska aktivnost; boja
• Keywords (english): High intensity ultrasound; sour cherry juice; bioactive compounds; antioxidant activity; color
• Language: croatian
• URN:NBN: urn:nbn:hr:159:635974
• Promotion: 2014-07-06
• Study programme: Title: Food Technology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti (doktor/doktorica znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2018-05-17 09:42:44