In situ observation of the distribution and location of gliadin as a function of mixing time in wheat flour dough using quantum dots

Bozkurt, Fatih

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https://hdl.handle.net/2142/46711 Copy

Description

Title

In situ observation of the distribution and location of gliadin as a function of mixing time in wheat flour dough using quantum dots

Author(s)

Bozkurt, Fatih

Issue Date

2014-01-16T17:59:57Z

Director of Research (if dissertation) or Advisor (if thesis)

Kokini, Jozef L.

Department of Study

Food Science & Human Nutrition

Discipline

Food Science & Human Nutrition

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Gliadin
• quantum dots
• Confocal laser scanning microscopy (CLSM)
• antibody
• dough

Abstract

Gliadins are a group of cereal proteins extracted from wheat flour. Gliadins contribute to viscosity and extensibility in dough. In our study, distribution and location of gliadins as a function of mixing time in model wheat flour dough were investigated for the first time using confocal laser scanning microscopy. In this research we tagged gliadin proteins with Quantum Dots (QDs) to increase the clarity and specificity of imaging and then investigated the effect of different mixing conditions on distribution of gliadin proteins and their role in building food structure/texture and quality. Dough samples were prepared in a 300 g Brabender farinograph instrument. A complete farinogram was obtained. The mixing times chosen were the arrival time (AT), peak time (PT), departure time (DT) and breakdown time (5 min after departure time). Small pieces of dough (approx. 4x4x4mm) were taken from the farinograph bowl and were immediately frozen using liquid nitrogen. The samples were cyro-sectioned to a thickness of 6 μm using cryostat. Auto-fluorescence of dough was removed by soaking small pieces of samples in 10 mL aqueous solution of Heparin. Quantum dots were conjugated to anti-gliadin antibody with a covalent crosslinker. Dough sections were conjugated with antibody-QDots mixture. CLSM (Zeiss Lsm 700) was used to investigate the locations of gliadin. Excitation wavelengths of 405 nm and 615 nm were selected for the reflection and fluorescence signal respectively. We also utilized the Image J program to be able to quantify images obtained from CLSM. We found that antibody-QDots mixture successfully bonded to gliadins located on dough sections. The images obtained from dough sections were very bright and clear that allowed us to distinguish gliadin easily. The QDs were found to be localized not only around the air cells as indicated by higher intensities but also in the bulk dough. We also observed that mixing plays an important role in distribution of gliadin proteins. Quantum Dots can be used as fluorophore probes to tag and track proteins of interest in food microstructures.

Graduation Semester

2013-12

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http://hdl.handle.net/2142/46711

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Copyright 2013 Fatih Bozkurt

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