Utjecaj ultrazvuka visoke snage na reološka i fizikalna svojstva suspenzija krumpirovog škroba

master's thesis

• Title (english): Effect of power ultrasound of rheological and physical properties of potato starch
• Author: Mislav Muža
• Mentor: Anet Režek Jambrak (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: 2009-10-07, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

U ovom radu željelo se istražiti kako ultrazvuk visoke snage utječe na reološka, teksturalna te fizikalna svojstva suspenzija krumpirovog škroba. Pripremljene 10 %-tne modelne suspenzije krumpirovog škroba tretirane su ultrazvukom. Sva ispitivanja provedena su prije i nakon obrade ultrazvukom visoke snage, pri frekvenciji od 22 kHz u ultrazvučnoj kupelji nominalne snage (150 W), te pri frekvenciji od 24 kHz ultrazvučnom sondom nominalne snage (100, 300 i 400 W) u vremenu od 15 i 30 minuta. Određeni su reološki parametri, te maksimalna viskoznost i početak želatinizacije primjenom Micro Visco-Amylo-Graph-a. Diferencijalnom motridbenom kalorimetrijom (DMK) određena je entalpija želatinizacije (ΔH), dok je iz egzotermne krivulje želatinizacije određen početak procesa (To), temperatura vrha krivulje (Tp) i temperatura završetka procesa želatinizacije (Te). Teksturalna svojstva određena su primjenom analizatora teksture. Mikrografijom 10%-tnih suspenzija nativnog i ultrazvukom modificiranog krumpirovog škroba utvrđene su promjene u morfološkoj strukturi škroba nakon tretmana ultrazvukom. Reološki parametri ukazuju da su sve suspenzije imale nenewtonski karakter. Rezultatima ispitivanja utvrđeno je da su svojstva bubrenja i topljivosti u direktnom odnosu s reološkim i teksturalnim svojstvima. Početak želatinizacije je pri višoj temperaturi kod svih modelnih suspenzija u odnosu na nativni škrob. Jasno se mogu zaključiti osnovna svojstva škroba: retrogradacija i želatinizacija. Utvrđeno je da ultrazvuk izlazne snage 400 W najviše degradira škrobnu granulu.

Abstract (english)

The aim of this thesis was to examine the influence and effect of power ultrasound on rheological, textural and physical properties of potato starch. Suspensions containing ten percent of potato starch have been treated with ultrasound. All analysis has been carried out before and after power ultrasound treatment. Ultrasound bath of 22 kHz frequency and nominal power of 150 W has been used, as well as ultrasound probe of 24 kHz frequency and nominal power of 100, 300 and 400 W for 15 and 30 minute treatments. Rheological parameters, pasting properties with Micro Visco-Amylo-Graph have been determined as well as enthalpy, onset and end temperature of gelatinization with Differential scanning calorimetry. Textural properties have been determined with Texture Analyser. Micrographical pictures of ten percent suspensions of native and ultrasound treated potato starch showed changes in morphological structure of starch after ultrasound treatment. Rheological parameters showed that all suspensions exhibited non-newtonian (dilatant) character. It was determined that swelling and solubility properties are in direct correlation with rheological and textural properties. Onset gelatinization temperature is higher for all model suspensions as compared to native starch. From the data one can observe obvious basic starch properties: retrogradation and gelatinization. It was determined that treatment with 400 W nominal power has the highest deterioration properties on starch granule.

• Keywords: krumpirov škrob; ultrazvuk visoke snage; reologija; tekstura; fizikalna svojstva
• Keywords (english): potato starch; power ultrasound; rheology; texture; physical properties
• Language: croatian
• URN:NBN: urn:nbn:hr:159:218237
• 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: 2017-08-31 12:17:54