the physiochemical properties of gluten-free dough with the addition of hydrocolloids and proteins

172 Pages·2009·1.42 MB·English

The Physicochemical Properties of Gluten-Free Dough with the Addition of
Hydrocolloids and Proteins

Thesis

Presented in Partial Fulfillment of the Requirements for the Degree Master of Science
in the Graduate School of The Ohio State University

By
Rachel Crockett, B.S.
Graduate Program in Food Science and Technology

The Ohio State University

2009

Thesis Committee:
Dr. Yael Vodovotz, Advisor
Dr. Sheryl Barringer
Dr. Mike Mangino
Copyright by
Rachel Crockett
2009
ABSTRACT

Gluten, the wheat protein that gives bread an open-cell crumb structure and
flexibility, can not be tolerated by individuals afflicted with Celiac disease. The only
treatment is life-long adherence to a gluten-free lifestyle. However, Celiac suffers crave
many foods that contain gluten, such as bread, and therefore a need exists to provide high
quality gluten-free baked goods. Hydrocolloids are commonly used to bind water and
provide additional structure to gluten-free bread. However, published research has not
studied the hydrocolloid alone, but in conjunction with alternative proteins contributing
to the overall variability of the hydrocolloids behavior. To better understand the
physicochemical changes imparted by hydrocolloids and protein on gluten-free bread,
two hydroxypropyl methylcelluloses (HPMC) and xanthan gum were investigated at 2, 3,
and 5% in rice cassava dough without the addition of alternative proteins. The formulated
doughs were analyzed using thermoanalytic and rheological techniques to determine the
role of water and subsequent flow behavior upon hydrocolloid addition. The baked loaves
were then measured for specific loaf volume and tensile strength to determine loaf
quality. The deconvoluted peaks of the derivatized thermogravimetric curves revealed
that hydrocolloid-added dough held water tighter than the control with an additional
water distribution at 85-88ºC. While the increase of elastic moduli in the low methoxy
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HPMC and xanthan-added dough became more pronounced with addition, both HPMC
formulations had increased viscous moduli allowing the gas cells to expand without
collapsing. The final specific loaf volume increased with high methoxy HPMC loaves (2-
5%) and low methoxy HPMC (2%) but was depressed with increased addition of low
methoxy HPMC (5%) and xanthan (3 and 5%). Crumb firmness was decreased in high
methoxy HPMC loaves but was increased significantly in low methoxy HPMC (5%) and
xanthan (5%) formulations. From the formulations studied it was concluded that high
methoxy HPMC was the optimum hydrocolloid in gluten-free dough.
The rice cassava formulation with 5% high methoxy HPMC was further analyzed
to determine hydrocolloid and alternative protein interactions with water in the gluten-
free bread. Soy protein isolate was investigated at 1, 2, and 3% while egg white solids
were investigated at 5, 10, and 15%. The formulated doughs were subjected to similar
analysis as was performed for the hydrocolloid experiment. The addition of soy protein
isolate and egg white solids reduced dough stability by suppressing HPMC functionality,
reducing available water, weakening HPMC interactions with the starch matrix, and
reducing foam stability. However, at 15%, egg white solids became the primary protein
scaffolding in the dough and overcame negative interactions with HPMC, improving loaf
volume and crumb regularity by forming an interconnected honeycomb matrix.
Overall, while the addition of proteins and HPMC improved the rice cassava
bread, there was an antagonistic interaction between the proteins and HPMC reducing the
water binding ability and functionality of the HPMC.

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Dedicated to my parents, my twin sister, Rebecca, and the love of my life, Val Staples.
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ACKNOWLEDGEMENTS

This thesis would not have been possible without the combined effort of my
graduate committee members Dr. Yael Vodovotz, Dr. Sheryl Barringer, and Dr. Mike
Mangino providing counsel and feedback on coursework and thesis. Foremost, I would
like to express my sincerest gratitude to my advisor, Dr. Yael Vodovotz, for her
continuous support, wealth of knowledge, and guidance throughout the whole project. It
would be hard to imagine completing the research without her.
In addition, I would like to extend my gratitude to Jennifer Saunders, CEO of
Around the World Gourmet®, for proposing the project to Dr. Vodovotz and co-
investigating it with Dr. Vodovotz. I would also like to thank the Center for Innovation
and Food Technology for providing funding for the research. Furthermore, I would like
to thank Dr. Valente Alvarez, Paul Courtright, and Gary Wenneker for providing me the
use of the Food Industry Center pilot plant and making sure I was provided the needed
equipment for the bakes. I would also like to thank Jerry Conklin for explaining the
intricacies of HPMC.
Finally, I would like to thank my lab mates for their help. Such as, Alex Siegwein
and Ruth Lucius help in introducing me to the equipment in the lab and passing on their
valuable knowledge on rheology and thermal analysis. I would also like to thank Sunny
Modi and Luca Serventi for taking the same chemical engineering and material science
classes with me so that we may pool our understanding of it. In addition, to Jennifer Ahn-
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Jarvis for sharing her experiences with up-scaling research formulations and her depth of
understanding on instrumentation and research design. And finally, I would also like to
thank Amber Simmons not only for providing me with support but also with her help
proof-reading and editing the thesis.
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VITA

January 8th, 1980 ………………….. Born – Columbus AFB, Mississippi USA.

2000………………………………... Associates of Science in Hospitality Management,
Culinary Option at Sinclair Community College.

2007………………………………... Bachelor of Science in Food Science & Technology
―Magna Cum Laude‖ at The Ohio State University.

2007-2009…………………………. Graduate Research Assistant at The Ohio State
University. Master of Science in Food Science &
Technology emphasizing physicochemical
properties of gluten and gluten-free bread.

FIELD OF STUDY
Major Field: Food Science & Technology
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TABLE OF CONTENTS
Page

Abstract ………………………………………………………………………………….ii
Dedication ………………………………………………………………………………..iv
Acknowledgments ……………………………………………………………………......v
Vita ……………………………………………………………………………………...vii
List of Figures ………………………………………………………………………......xiii
List of Tables …………………………………………………………………………..xvii
List of Abbreviations …………………………………………………………………...xix
Chapters
1. Introduction …………………………………………………………………………...1
2. Statement of the Problem …………………………………………………………......4
3. Literature Review …...………………………………………………………………...6
3.1 Celiac Disease …………………………………………………………….....6
3.2 Biochemical Basis for Celiac Disease ……………………………………….8
3.3 Gluten ……………………………………………………………………….11
3.4 Gluten-free Compared to Traditional Wheat ………………………………..15
3.5 Importance of Water Behavior Analysis ………………………………….....19
3.6 Importance of Rheological Analysis …………………………………...........24
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3.7 Importance of Bread Quality Analysis ………………………………….......30
3.8 Material Refinement …………………………………...................................32
3.8.1 Soy Protein Isolate ………………………………….......................33
3.8.2 Egg White Solids ………………………………….........................34
3.8.3 Hydrocolloids …………………………………...............................34
4. Materials and Methods …………………………………..............................................39
4.1 Materials ………………………………….....................................................39
4.2 Wheat and Gluten-free Dough and Bread
Formulations ………………………………….........................................40
4.3 Dough and Bread Preparation ………………………………….....................43
4.4 Thermal Analysis …………………………………........................................44
4.4.1 Differential Scanning Calorimeter ………………………………...44
4.4.2 Thermogravimeteric Analyzer ………………………………….....45
4.5 Rheological Analysis …………………………………..................................46
4.6 Bread Quality Analysis …………………………………...............................46
4.7 Image Acquisition of Dough and Bread Crumb …………………………….47
4.8 Statistical Analysis………………………………….......................................48
5. Hydropropylmethylcellulose Improves Physiochemical
Properties of Model Gluten-free Bread ………………………………….............49
5.1 Introduction ………………………………….................................................49
5.2 Method & Materials …………………………………....................................54
5.2.1 Basic Ingredients and Additives …………………………………..54
5.2.2 Bread Formulation and Bread Making
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