Utjecaj ultrazvuka na stabilnost flavan-3-ola i antioksidacijski kapacitet u mutnom soku od jabuke

master's thesis

• Title (english): The effect of ultrasound on the stability of flavan-3-ols and antioxidant capacity in cloudy apple juice
• Author: Blaženka Buntić
• 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: 2018-07-19, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Cilj ovog istraživanja bio je ispitati stabilnost flavan-3-ola i vrijednosti antioksidacijskog kapaciteta (FRAP) u mutnom soku od jabuke uslijed tretmana ultrazvukom te tijekom 7 dana skladištenja na +4 °C. Sokovi od jabuke tretirani su ultrazvukom visokog intenziteta uz variranje amplitude (40 i 80 %), promjera sonde (7 i 10 mm) i vremena tretiranja (3, 6 i 9 min). Antioksidacijski kapacitet i flavan-3-oli određeni su spektrofotometrijski. Utjecaj ultrazvuka na vrijednost masenih udjela flavan-3-ola pokazao je negativan trend u većini uzoraka, osim u uzorcima UZ-6, UZ-8, UZ-11 i UZ-12 gdje je došlo do značajnog povećanja. Primjena ultrazvuka značajno je utjecala i na smanjenje antioksidacijskog kapaciteta u svim uzorcima neovisno o amplitudi, promjeru sonde i vremenu tretiranja u odnosu na svježi sok. Vrijeme skladištenja također se izdvojilo se kao signifikantan čimbenik sa nepovoljnim doprinosom stabilnosti flavan-3-ola i antioksidacijskog kapaciteta.

Abstract (english)

The main goal of this work was to investigate the stability of flavan-3-ols and antioxidant capacity in cloudy apple juice during seven-day refrigerated storage at 4 °C. Immediately after pressing, juice samples were treated with High Power Ultrasound (HPU) according to the experimental design with 40% and 80% amplitude levels, ultrasound probe 7 mm and 10 mm for 3, 6 and 9 min. Flavan-3-ols and antioxidant capacity were determined according to previously described spectrophotometric methods. With no significant impact of amplitude level, ultrasound probe and the treatment, obtained results suggest that HPU has negative effect on the stability of flavan-3-ols and antioxidant capacity, except for the samples UZ-6, UZ-8, UZ-11 and UZ-12, where the greatest stability and even increasing was observed. With respect to the shelf-life, it could be concluded that seven-days of storage at 4 °C negatively affect the flavan-3-ols concentration and antioxidant capacity.

• Keywords: ultrazvuk; sok od jabuke; flavan-3-oli; FRAP; skladištenje
• Keywords (english): ultrasound; apple juice; flavan-3-ols; FRAP; storage
• Language: croatian
• URN:NBN: urn:nbn:hr:159:854647
• 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: Access restricted to students and staff of home institution
• Created on: 2019-11-27 11:54:57