Utjecaj ultrazvuka visokog intenziteta na stabilnost fenolnih spojeva i antioksidacijski kapacitet u mutnom soku od jabuke

master's thesis

• Title (english): The effect of ultrasound on the stability of phenols and antioxidant capacity in cloudy apple juice
• Author: Josipa Bilobrk
• 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: 2018-07-18, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Cilj ovoga rada bio je istražiti utjecaj ultrazvuka na stabilnost fenolnih spojeva i antioksidacijskog kapaciteta te usporediti dobivene rezultate s rezultatima svježeg netretiranog mutnog soka od jabuke sorte Zlatni Delišes neposredno nakon tretmana te tijekom sedmodnevnog skladištenja pri 4 °C. U radu je korišten ultrazvuk visokog intenziteta, snage 100 W, frekvencije 20 kHz, amplituda 40 % i 80 %, promjera sondi 7 i 10 mm te vremena tretiranja od 3, 6 i 9 minuta. Uslijed tretmana ultrazvukom, temperatura nije prelazila 41 ˚C. U odnosu na kontrolni uzorak u svim tretiranim uzorcima neovisno o amplitudi, promjeru sondi te vremenu tretiranju uočen je smanjen udio ukupnih fenola i antioksidacijskog kapaciteta. Nakon 7 dana skladištenja, kod svih uzoraka, tretiranih i netretiranih, došlo je do smanjenja navedenih vrijednosti. Uslijed skladištenja, veći pad vrijednosti primijećen je kod uzoraka tretiranih ultrazvukom.

Abstract (english)

The aim of this study was to investigate the influence of ultrasound treatment on the stability of phenolic compounds and antioxidant capacity in cloudy apple juice (cv. Golden Delicious) during seven days storage at 4 °C. For this purpose, the High Power Ultrasound (HPU) (100 W, 20 kHz frequency) was operated at following conditions: (i) amplitude 40 % and 80 %, (ii) ultrasound probe 7 and 10 mm, and (iii) treatment time of 3, 6 and 9 minutes. The temperature did not exceed 41 °C during any of the ultrasound treatments. Aside from the amplitude, ultrasound probe and treatment time, obtained results revealed that ultrasound treatment decreased total phenols and antioxidant capacity in cloudy apple juices. Moreover, seven days of storage at 4 °C also has negative impact on polyphenols stability and antioxidant capacity. However, during shelf-life, the greater stability of both, polyphenols and antioxidant capacity, was observed in all un-treated samples.

• Keywords: sok od jabuke; ukupni fenoli; ultrazvuk; antioksidacijski kapacitet; skladištenje
• Keywords (english): apple juice; ultrasound; total phenols; antioxidant capacity; storage time
• Language: croatian
• URN:NBN: urn:nbn:hr:159:323774
• 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: 2019-11-28 10:30:32