Utjecaj ultrazvuka na reološka, teksturalna i fizikalna svojstva pšeničnog škroba

master's thesis

• Title (english): The influence of ultrasound on rheological, textural and physical properties of wheat starch
• Author: Zoran Werner
• 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: 2010-03-05, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Svrha ovog rada bila je utvrditi djelovanje ultrazvuka različitih snaga i vremena tretiranja na reološka, teksturalna i različita fizikalna svojstva suspenzija pšeničnog škroba. Na modelne suspenzije pšeničnog škroba primijenjen je tretman ultrazvučnom sondom (20 kHz) nominalne snage 600W. Korištene su dvije amplitude (75% i 100%) i različita vremena tretiranja (5, 10 i 15 min). Osim ultrazvučne sonde korišten je i tretman s ultrazvučnom kupelji (22 kHz) nominalne snage 150W i vremenima tretiranja od 10 i 15 minuta. Ispitivanjem reoloških svojstava (indeks tečenja, koeficijent konzistencije) utvrñeno je kako sve suspenzije pokazuju ne- Newtonovski karakter. Tretman ultrazvukom uzrokovao je promjene na elastičnosti, kohezivnosti, adhezivnosti i gumenosti škrobnih gelova, pri čemu je povećanje vremena ultrazvučnog tretiranja modelnih suspenzija pšeničnog škroba dovelo do smanjenja čvrstoće nastalih gelova. Viskoznost modelnih suspenzija pšeničnog škroba porasla je s vremenom tretiranja, a maksimalna viskoznost postignuta je primjenom tretmana ultrazvučne sonde korištenjem 100%-tne amplitude. Mikrografija modelnih suspenzija je pokazala narušavanje strukture i smanjenje veličine promatranih škrobnih granula primjenom ultrazvučnog tretmana.

Abstract (english)

The aim of this study was to determine the influence of ultrasound on rheological, textural and various physical properties of model wheat starch suspensions using different treatment times and power settings. Suspensions were treated with 600W nominal power ultrasound probe (20 kHz) by applying two types of amplitude (75% and 100%) and different treatment times (5, 10 and 15 min). Besides power ultrasound probe set, ultrasound bath of 150W nominal power and 22 kHz frequency was used. Treatment times were 10 and 15 minutes. Examination of rheological properties (flow index, consistency coefficient) showed that all suspensions have non-Newton characteristics. The ultrasound treatment induced changes in springiness, cohesiveness, adhesiveness and gumminess of starch gels, with decrease in starch gel hardness by applying longer treatment times. Model wheat starch suspension viscosity values have risen by applying longer treatment times, while maximum viscosity was achieved by applying ultrasound probe treatment of 100% amplitude value. Micrography of model suspensions showed that the use of ultrasound treatment degraded the structure and reduced the size of observed starch granules.

• Keywords: ultrazvuk; pšenični škrob; reologija; teksturalna svojstva; fizikalna svojstva
• Keywords (english): ultrasound; wheat starch; rheology; textural properties; physical properties
• Language: croatian
• URN:NBN: urn:nbn:hr:159:442026
• Study programme: Title: Food Technology; specializations in: Nutrition; Course: Nutrition; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer prehrambene tehnologije; smjer nutricionizam (diplomirani inženjer prehrambene tehnologije; smjer nutricionizam)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-08-29 07:59:56