Kemijske promjene tijekom postupka ekstruzije-esterska veza

master's thesis

• Title (english): Chemical changes during the extrusion process - ester bond
• Author: Danijel Rožanković
• 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: 2005-01-21, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

U ovom radu razvijen je model za proučavanje i interpretaciju nastanka esterske izopeptidne veze u proteinima pšenične krupice tijekom procesa ekstruzije. Modelni sistem je razvijen na molekulama aminokiselina: asparaginska kiselina, glutaminska kiselina, serin i treonin, te modelnim diizopeptidima: asparaginska kiselina -serin, asparaginska kiselina-treonin, glutaminska kiselina-serin i glutaminska kiselina-treonin. U radu je korišten teorijski pristup baziran na metodama molekularnog modeliranja u kombinaciji s eksperimentalnim pristupom u kojem je korištena FTIR spektroskopija. Metode molekularnog modeliranja obuhvaćale su semiempirijske AM1 i ab initio HF/6-31G* kvantno mehaničke račune. Molekularnim modeliranjem dobivene su vibracijske frekvencije u području od 1180 do 1300 cm -1 što odgovara nastanku esterske veze između zadanih peptida. Dobiveni vibracijski spektri uspoređeni su s FTIR spektrima ekstrudata pšenične krupice koji su također pokazali smanjenje u apsorpciji pri valnom broju oko 1182,2 cm-1 ( za uzorak dobiven na temperaturi od 120 °C ) te 1290,2 cm-1 ( za uzorak dobiven pri 170 °C ) što je naznačilo prisustvo esterske veze.

Abstract (english)

In this work a model for interpretation of ester isopeptid bond in wheat semolina during the process of extrusion was developed. Model system was tested on aminoacides: aspartic acid, glutamic acids, serin and threonin and model diisopeptides: aspartic acid-serin, aspartic acid-threonin, glutamic acid-serin and glutamic acid-threonin. This study used theoretical approach based on molecular modeling methodes and experimental approach based on FTIR spectroscopy. Molecular modeling methodes included semiempirical AM1 and ab initio HF/6-31G* quantum machanical calculations. Performed calculations gave vibrational frequencies in the range from 1180 to 1300 cm-1. Calculated spectra were compared with FTIR spectra of wheat semolina extrudates that have shown reduced absorption at 1182,2 cm-1 ( at 120 °C ) and 1290,2 cm-1 ( at 170 °C ) indicating the presence of ester bond.

• Keywords: ekstruzija; esterska veza; FTIR spektroskopija; molekularno modeliranje; proteini
• Keywords (english): extrusion; ester bond; FTIR spectroscopy; molecular modeling; proteins
• Language: croatian
• URN:NBN: urn:nbn:hr:159:144014
• 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: 2017-09-13 09:09:04