Utjecaj ultrazvuka visokog intenziteta na bioaktivne spojeve heljdinih ljuskica

master's thesis

• Title (english): Influence of high intensity ultrasound on the bioactive compounds of the buckwheat hulls
• Author: Andrea Buratović
• Mentor: Dubravka Novotni (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: 2019-09-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Heljdine ljuskice nusproizvod su postupka ljuštenja heljdinog zrna a predstavljaju važan izvor vlakana i bioaktivnih spojeva zbog čega im se pripisuju brojni pozitivni zdravstveni učinci. Cilj ovog rada bio je ispitati utjecaj ultrazvuka visokog intenziteta (400 W, 24 kHz) na povećanje udjela slobodnih bioaktivnih spojeva, antioksidacijsku aktivnost, sposobnost bubrenja u vodi i aktivnost enzima polifenol oksidaze heljdinih ljuskica. Vodena suspenzija heljdinih ljuskica različitih temperatura (9,7; 20; 45; 70 ili 80,4 °C) tretirana je (2,9; 5; 10; 15 ili 17 min) direktno uronjenom ultrazvučnom sondom (d = 22 mm) pri 100 % amplitude prema složenom centralnom planu pokusa. Usporedbom tretiranih uzoraka u odnosu na kontrolu utvrđeno je da tretman povećava udio ukupnih fenolnih spojeva, antioksidacijsku aktivnost, sposobnost bubrenja u vodi i aktivnost polifenol oksidaze. Optimizacija procesa pokazala je da se najbolji učinak postiže kod uzorka temperature 20 °C u trajanju tretmana 15 min što rezultira 22 % većoj FRAP antioksidacijskoj aktivnosti i 106 % većoj aktivnosti polifenol oksidaze.

Abstract (english)

Buckwheat hulls are a by-product of the milling industry and an important source of dietary fibre and bioactive compounds with numerous beneficial health effects. This work aimed to investigate the effect of high intensity ultrasound (400 W, 24 kHz) on the release of bioactive compounds, antioxidant activity, water swelling and activity of enzyme polyphenol oxidase of buckwheat hulls. Water suspension of hulls was treated (2,9; 5; 10; 15 or 17 minutes) by direct immersion of the ultrasound probe (d = 22 mm) and amplitude of 100 %, at different temperatures (9,7; 20; 45; 70 or 80,4 °C) following a central composite design. In comparison to the control sample, high intensity ultrasound had a positive effect on total phenolic content, antioxidant activity, water swelling and polyphenol oxidase activity. Optimization of the process showed that the best results are achieved with temperature sample 20 °C and 15 min treatment time, resulting in 22 % increase of FRAP antioxidant activity and 106 % polyphenol oxidase activiy.

• Keywords: bioaktivni spojevi; heljdine ljuskice; polifenol oksidaza; ultrazvuk visokog intenziteta
• Keywords (english): bioactive compounds; buckwheat hulls; polyphenol oxidase; high intensity ultrasound
• Language: croatian
• URN:NBN: urn:nbn:hr:159:151383
• 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: 2020-01-28 12:29:04