Određivanje reoloških svojstava proteina sirutke u interakciji sa škrobom pri pH = 5

master's thesis

• Title (english): Rheological properties of whey protein and starch at pH=5
• Author: Marina Torić
• 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: 2007-07-09, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Reologija je grana fizike koja se bavi proučavanjem deformacija krutih i tekućih materijala podvrgnutih djelovanju sile. Pod deformacijom ili tečenjem podrazumijeva se promjena oblika i dimenzija nekog materijala nastala pod utjecajem različitih sila. Svrha ovog rada bila je proučiti u kojoj će mjeri interakcija proteina sirutke sa škrobom utjecati na reološka svojstva pri pH=5, te s obzirom na tribomehaničku aktivaciju utvrditi postojanje eventualne razlike u reološkim svojstvima. Na reološka svojstva hrane utječu temperatura, procesni parametri, kemijski sastav, te posebno udio i vrsta suhe tvari. Utjecaj temperature na suspenzije proteina sirutke i škroba ispitan je na 10%-tnim modelnim suspenzijama proteina sa dodatkom škroba. Određivanje viskoznosti ispitivanih modelnih sustava provedena su na rotacionom reometru Rheometric Scientific RM-180 u temperaturnom rasponu od 10-70 ° C. Reološka svojstva ispitivanih suspenzija proteina izražena su reološkim parametrima pomoću Ostwald de Waele-ovog zakona. Znatno viša vrijednost viskoznosti zabilježena je u modelnim sustavima tretiranog izolata proteina sirutke sa dodatkom škroba nego u modelnoj otopini sa netretiranim IPS. Utjecaj temperature na viskoznost modelnih suspenzija ispitan je primjenom Arrhenius-ovog modela. Povišenjem temperature dolazi do kontinuiranog smanjenja viskoznosti u svih ispitivanih sustava.

Abstract (english)

Rheology as a science studies the deformation of solid and liquid materials submitted to the influence of the force. Deformation or flowing implies configuration and dimensional changes of a certain material resulted under influence of the force. The purpose of this work was to which extent will the interaction of whey proteins with starch affect rheological attributes in temperature range of 10 - 70ºC, pH=5 and according to tribomechanical activation in order to determine the existance of probable variation in rheological attributes. Temperature, process parameters, chemical composition, especially the content and the type of a solid matter have a significant influence on the rheological properties of food. The influence of temperature change on rheological parameters was tested on 10 % whey protein- starch model suspensions. All rheological properties of our suspensions were determinated using a rotational viscosimeter, Rheometric Scientific RM-180, in temperature range 10-70 °C. Rheological parameters were described by Ostwald de Waele power- law model. The influence of temperature was determined by Arrhenius equation. The growth of temperature causes a continuous decrease of viscosity in every suspension we used.

• Keywords: reološka svojstva; proteini sirutke; škrob
• Keywords (english): rheological properties; whey protein; starch
• Language: croatian
• URN:NBN: urn:nbn:hr:159:921708
• 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: 2017-09-07 07:38:50