Utjecaj tretiranja ultrazvukom na emulgirajuća svojstva suspenzija proteina sirutke

master's thesis

• Title (english): Effect of the ultrasound treatment on emulsifying properties of whey protein suspension
• Author: Irma Sokolić
• Mentor: Zoran Herceg (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Food Processes Engineering); Zagreb
• Defense date and country: 2007-10-10, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Svrha ovog istraživanja je ispitati utjecaj ultrazvuka na emulgirajuća svojstva proteina sirutke. Utjecaj ultrazvuka na fizikalno-kemijska i funkcionalna svojstva praćen je mjerenjem temperature, pH te određivanjem mutnoće, indeksa aktivnosti emulzije i indeksa stabilnosti emulzije. U ovom su radu korišteni ultrazvuk niskog intenziteta (<1 W·cm-2) te ultrazvuk visokog intenziteta (43-48 W·cm-2). 10%-tne modelne suspenzije izolata, koncentrata te hidrolizata proteina sirutke kao i α-laktalbumina tretirane su ultrazvučnom sondom (20 kHz, 15 i 30 min) te ultrazvučnom kupelji (40 kHz te 500 kHz, 15 i 30 min). Vrijednosti temperature su se povećale kod svih tretiranja modelnih suspenzija, a najviše kod tretiranja ultrazvučnom sondom frekvencije 20 kHz. pH vrijednosti se nisu znatno promijenile. Indeks aktivnosti emulzije povećao se za sve uzorke koncentrata proteina sirutke. Kod hidrolizata i α-laktalbumina taj je indeks porastao prilikom ultrazvučnog tretiranja frekvencije 20 kHz/15 i 30 min te 40 kHz/15 min. Indeks stabilnosti emulzije značajno se povećao za sve uzorke proteina sirutke. Nije primijećeno nikakvo poboljšanje emulgirajućih svojstava za modelne suspenzije proteina pri ultrazvučnom tretiranju frekvencije 500 kHz.

Abstract (english)

The aim of this study was to observe the effect of ultrasound treatment on emulsifying properties of whey proteins. Effect of ultrasonud treatment on physicochemical and functional properties was examined by temperature, pH and turbitity, emulsion activity index and emulsion stability index. In this work low-intensity ultrasound (<1 W·cm-2) and high-intensity ultrasound (43-48 W·cm-2) were used. 10% wt. protein model suspensions of whey protein isolate (WPI); whey protein concentrate (WPC); whey protein hydrolysate (HWP) and α-lactalbumin were treated with ultrasound probe (20 kHz for 15 and 30 minutes) and ultrasound baths (40 kHz and 500 kHz for 15 and 30 minutes). Temperatures increased for all whey protein samples upon ultrasound treatment, and the highest upon ultrasound treatment for 20 kHz/15, 30 min. pH didn't change significantly upon ultrasound treatment. Emulsion activity index (EAI) increased for all samples of WPC. For HWP and α- lactalbumin EAI increased upon ultrasound treatments for 20 kHz/15, 30 min and 40 kHz/15 min. Emulsion stability index increased significantly for whey protein samples. No-improvement in emulsifying properties for protein model suspensions for 500 kHz treatments was observed.

• Keywords: fizikalno-kemijska svojstva; funkcionalna svojstva; proteini sirutke; ultrazvuk niskog intenziteta; ultrazvuk visokog intenziteta
• Keywords (english): functional properties; high-intensity ultrasound; low-intensity ultrasound; physicochemical properties; whey proteins
• Language: croatian
• URN:NBN: urn:nbn:hr:159:077034
• Study programme: Title: Food Technology; specializations in: Food Engineering; Course: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo (diplomirani inženjer prehrambene tehnologije; smjer prehrambeno inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-09-06 07:34:01