Utjecaj ultrazvuka visokog intenziteta na bioaktivne spojeve posija prosa

master's thesis

• Title (english): Influence of high intensity ultrasound treatment on the bioactive compounds of the millet bran
• Author: Anamarija Gudelj
• Mentor: Nikolina Čukelj Mustač (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Cereal Chemistry and Technology); Zagreb
• Defense date and country: 2018-07-19, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Posije su nusproizvod procesa mljevenja žitarica i važan izvor vlakana, mikronutrijenata i fitokemikalija te im se pripisuju brojni povoljni učinci na zdravlje. U ovom radu ispitan je utjecaj tretmana ultrazvuka visokog intenziteta (UVI) (400 W, 24 kHz) na učinkovitost oslobađanja bioaktivnih spojeva posija prosa i na njihov antioksidacijski kapacitet. Vodena suspenzija posija tretirana je 5, 12,5 ili 20 minuta direktno uronjenom ultrazvučnom sondom (d = 22 mm) pri 60 %, 80 % ili 100 % amplitude, prema složenom centalnom planu pokusa. Ukupni slobodni polifenolni spojevi određeni su Folin-Ciocalteu, a antioksidacijska aktivnost ABTS, DPPH i FRAP metodama. U odnosu na kontrolni uzorak najviši udio ukupnih slobodnih polifenola i najveća antioksidacijska aktivnost određena je u posijama tretiranima 12,5 minuta pri 80 % amplitude, pri čemu je zabilježen porast od 25 % za ukupne fenole i 27 % za FRAP antioksidacijsku aktivnost. Optimizacija procesa pokazala je da UVI ovisi o vremenu tretmana, ali ne i o amplitudi

Abstract (english)

Bran is a by-product of milling industry and an important source of dietary fibre, micronutrients, phytochemicals with numerous beneficial health effects. This study explored the effect of high intensity ultrasound (HIU) (400 W, 24 kHz) on the release of free bioactive compounds and antioxidant activity of the millet bran. Water suspension of bran was treated for 5, 12,5 and 20 minutes by direct immersion of the ultrasound probe (d = 22 mm) and amplitude of 60 %, 80 % and 100 %, following a central composite design. The total phenolic content was determined by Folin-Ciocalteu and antioxidant activity using ABTS, DPPH and FRAP methods. In comparison to the control sample, the highest total phenolics and antioxidant capacity of millet bran was achieved after the 12,5 minute and amplitude of 80 %, resulting in 25 % increase of total free phenolic content and 27 % increase of FRAP antioxidant activity. Optimization of the process showed that UVI depends on the treatment time, but not on the amplitude.

• Keywords: antioksidacijski kapacitet; polifenoli; posije; proso; ultrazvuk visokog intenziteta
• Keywords (english): antioxidant capacity; bran; millet; polyphenols; high intensity ultrasound
• Language: croatian
• URN:NBN: urn:nbn:hr:159:880398
• 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 12:25:28