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Specific Salt Effects on the Formation and Thermal Transitions Among Β-Lactoglobulin and Pectin Electrostatic Complexes

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Specific Salt Effects on the Formation and Thermal Transitions Among Β-Lactoglobulin and Pectin Electrostatic Complexes Purdue University Purdue e-Pubs Open Access Theses Theses and Dissertations 2013 Specific altS Effects on the Formation and Thermal Transitions Among β-Lactoglobulin and Pectin Electrostatic Complexes Stacey Ann Hirt Purdue University, [email protected] Follow this and additional works at: https://docs.lib.purdue.edu/open_access_theses Part of the Agriculture Commons, Bioresource and Agricultural Engineering Commons, Food Science Commons, and the Physical Chemistry Commons Recommended Citation Hirt, Stacey Ann, "Specific altS Effects on the Formation and Thermal Transitions Among β-Lactoglobulin and Pectin Electrostatic Complexes" (2013). Open Access Theses. 34. https://docs.lib.purdue.edu/open_access_theses/34 This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. Graduate School ETD Form 9 (Revised 12/07) PURDUE UNIVERSITY GRADUATE SCHOOL Thesis/Dissertation Acceptance This is to certify that the thesis/dissertation prepared Stacey A. Hirt By ! Entitled! Specific Salt Effects on the Formation and Thermal Transitions Among "-Lactoglobulin and Pectin Electrostatic Complexes! Master of Science For the degree of Is approved by the final examining committee: Owen Jones Chair Yuan Yao Ganesan Narsimhan To the best of my knowledge and as understood by the student in the Research Integrity and Copyright Disclaimer (Graduate School Form 20), this thesis/dissertation adheres to the provisions of Purdue University’s “Policy on Integrity in Research” and the use of copyrighted material. Owen Jones Approved by Major Professor(s): ____________________________________ ____________________________________ Rengaswami Chandrasekaran 09/27/2013 Approved by: Head of the Graduate Program Date i SPECIFIC SALT EFFECTS ON THE FORMATION AND THERMAL TRANSITIONS AMONG β-LACTOGLOBULIN AND PECTIN ELECTROSTATIC COMPLEXES A Thesis Submitted to the Faculty of Purdue University by Stacey Ann Hirt In Partial Fulfillment of the Requirements for the Degree of i Master of Science December 2013 Purdue University West Lafayette, Indiana ii For my parents- Denny and Jackie. You may not understand what’s written on the following pages, but I owe it all to you ii iii ACKNOWLEDGEMENTS I would like to thank my parents for absolutely everything. Words cannot describe how grateful I am for the countless opportunities I’ve been given. Thanks for the gift of my education—the years I’ve spent at Villa and Purdue have shaped who I am. Thank you for pushing me hard, never letting me quit, and always expecting the best. I have learned more about myself, who I am, and who I want to be during graduate school than any other point in my life. I am so incredibly fortunate to have such amazing parents. I love you both. Thanks to my major professor, Owen Jones, for answering my endless barage of questions, teaching and training me especially during the first few months, and being beyond patient with me the past two years. I have learned so much during graduate school and I am repeatedly astounded by your knowledge of our field. Thank you to my iii committee members, Dr. Yao and Dr. Narsimhan, for the new perspectives you’ve brought to my project. Thanks to all the faculty and staff of the Purdue food science department who have helped me build a home and truly find my niche over the past six years. Thanks to the best lab partner a girl could ever ask for, Laura Zimmerer. Our constant dancing and singing in the lab helped me stay sane during graduate school. You were always there for me whether I needed a bit of motivation, time to vent, or a drink. iv I am so happy to have made a lifelong friend during graduate school. And if food science doesn’t pan out it’s nice to know we have our singing career or multiple business ideas to fall back on. Thanks to my friends, both in graduate school and away. Your words of encouragement and commiseration meant more than you will know. Thanks to Simran Kaur for being an amazing officemate and Alyssa Beatty for always forcing me to leave my desk during lunch. I couldn’t have made it through my Master’s without the help of my friends. And to my sisters, for listening to me complain, picking up the poor graduate student’s checks on vacations, and giving me a dose of city life outside of Lafayette. Finally, thank you to Kanye West. His music got me through countless hours of writing and lab work. There will never be a better album than The College Dropout. Ever. “See I know my destination, but I’m just not there.” –Kanye West iv v TABLE OF CONTENTS Page LIST OF TABLES ........................................................................................................... viii LIST OF FIGURES ............................................................................................................ ix LIST OF ABBREVIATIONS ........................................................................................... xii ABSTRACT ............................................................................................................. xiii CHAPTER 1. INTRODUCTION .................................................................................... 1 1.1 Introduction ......................................................................................................... 1 1.2 Objectives ............................................................................................................ 4 CHAPTER 2. LITERATURE REVIEW ......................................................................... 5 2.1 Introduction ......................................................................................................... 5 2.2 Protein-Polysaccharide Complex Constituents ................................................... 5 2.2.1 Proteins ................................................................................................... 6 2.2.1.1 β-Lactoglobulin ........................................................................................ 9 2.2.2 Polysaccharides ...................................................................................... 10 2.2.2.1 Pectin ...................................................................................................... 11 2.3 Interactions Influencing the Formation of Protein-Polysaccharide Complexes 12 2.3.1 Electrostatic Interactions ........................................................................ 13 2.3.2 Non-Electrostatic Interactions ................................................................ 14 v 2.3.2.1 Hydrogen Bonds ..................................................................................... 15 2.3.2.2 Hydrophobic Interactions ....................................................................... 15 2.3.2.3 Covalent Bonds ...................................................................................... 15 2.4 Factors Influencing Complex Formation .......................................................... 16 2.4.1 pH ................................................................................................. 16 2.4.2 Ionic Strength ......................................................................................... 17 2.4.3 Protein-Polysaccharide Concentration ................................................... 17 2.4.4 Charge Density ....................................................................................... 18 2.5 Specific Ion Effects ........................................................................................... 18 2.5.1 Stabilization of Proteins ......................................................................... 19 2.5.1.1 Chaotropes and Kosmotropes ................................................................. 20 vi Page 2.5.2 Nature of Electrolyte .............................................................................. 21 2.5.2.1 Anion and Cations .................................................................................. 21 2.5.3 Direct and Inverse Hofmeister Effects ................................................... 21 2.6 Applications for Protein-Polysaccharide Complexes ........................................ 23 2.6.1 Viscosifying and Gelling ....................................................................... 23 2.6.2 Foaming and Emulsifying ...................................................................... 24 2.6.3 Stabilization and Release of Bioactive Components ............................. 25 2.7 Conclusions ....................................................................................................... 26 CHAPTER 3. SPECIFIC ION EFFECTS ON ELECTROSTATIC INTERACTIONS AND COACERVATION OF AQUEOUS β-LACTOGLOBULIN AND PECTIN MIXTURES .............................................................................................................. 27 3.1 Abstract ............................................................................................................. 27 3.2 Introduction ....................................................................................................... 28 3.3 Materials and Methods ...................................................................................... 31 3.3.1 Materials ................................................................................................. 31 3.3.2 Biopolymer Solution Preparation ........................................................... 32 3.3.3 Colloidal Charge .................................................................................... 33 3.3.4 Solution Turbidity .................................................................................
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