Kemijske promjene na pšeničnim proteinima za vrijeme ekstruzije

master's thesis

• Title (english): Chemical changes in wheat protein during the extrusion process
• Author: Valentina Posarić
• Mentor: Damir Kovaček (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Chemistry and Biochemistry); (Laboratory for Analytical Chemistry); Zagreb
• Defense date and country: 2004-10-29, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

U ovom radu razvijen je model za proučavanje i interpretaciju nastanka amidne izopeptidne veze u proteinima pšenične krupice tijekom procesa ekstruzije. Modelni sistem je razvijen na molekulama aminokiselina : prolin, lizin, glutamin,te njihovim diizopeptidima prolin- lizin i prolin- glutamin. U radu je korišten teorijski pristup baziran na metodama molekularnog modeliranja kombinaciji s eksperimentalnim pristupom u kojem je korištena FT-IR spektroskopija. Od metoda molekularnog modeliranja obuhvaćeni su semiempirijski AM1 i Ab initio HF/6-31G* kvantnomehanički pristupi. Molekularnim modeliranjem dobivene su vibracijske frekvencije u području od 800 cm -1 do 1800 cm -1 što odgovara nastanku amidne izopeptidne veze. Dobiveni vibracijski spektri uspoređeni su s FT-IR spektrom ekstrudata pšenične krupice koji je pokazao smanjenje u apsorpciji pri valnom broju oko 1681,8 cm-1 (za uzorak dobiven na temperaturi od 120 °C) te 1674,0 cm-1 (za uzorak dobiven pri 170 °C) i naznačio postojanje amidne izopeptidne veze.

Abstract (english)

The aim of this study was to developed a model for studing and interpretation of amid isopeptide bond in wheat semolina during the process of extrusion. Model system is developed on aminoacides: prolin, lysin and glutamin and their diizopeptides: prolin- lysin and prolin- glutamin. Theoretical approach based on methods of molecular modeling has been applied along with the experimental approach based on FT-IR spectroscopy. Molecular modeling methodes were including semiempirical AM1 and ab initio HF/6-31G* quantum machanical calculations. Those methods gave vibrational frequencies in range from 800 – 1800 cm –1. This range corresponds to formation of amid isopeptide bond. Vibrational spectrums were compared with FT-IR spectra of wheat semolina extrudates that has shown reduction apsorption degrease wawe in range about 1681,8 cm -1 (at 120 °C ) and 1674,0 cm -1 (at 170 °C ) and point on presence of amid izopeptide bond.

• Keywords: ekstruzija; amidna izopeptidna veza; FTIR spektroskopija; molekularno modeliranje; proteini
• Keywords (english): extrusion; amid izopeptid bond; FTIR spectroscopy; molecular modeling; proteins
• Language: croatian
• URN:NBN: urn:nbn:hr:159:515825
• Study programme: Title: Biotechnology; specializations in: Biochemical Engineering; Course: Biochemical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo (diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-09-12 09:25:33