RETRONASAL OLFACTION AS AFFECTED BY MIRACLE FRUIT AND GYMNEMA SYLVESTRE By SONIA DARA HUDSON A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2011 1 © 2011 Sonia Dara Hudson 2 To my parents 3 ACKNOWLEDGMENTS I thank my supervisory committee: Dr. Charles Sims, Dr. Linda Bartoshuk, Dr. Renée Goodrich-Schneider, and Dr. Bruce Welt for all of your knowledge and guidance throughout this study. I especially thank Dr. Sims for serving as my major advisor and giving me the opportunity to pursue my graduate degree. I also thank Dr. Bartoshuk for all of her support and countless hours helping me analyze the data. I thank all of my labmates past and present – Adilia Blandón-Ubeda, Betty Natasha Coello, Eric Dreyer, Brittany Martin, Dr. Asli Odabasi, and Lorenzo Puentes. Thanks for all of your help with the informal tasting sessions! I could not have selected my foods without all of you. Thank you Lorenzo for showing me how to use Compusense and putting together the design. Thank you Adilia and Eric for setting up and running the panels. Thank you Asli for all of your help with the statistical analysis. Thank you Betty and Brittany for your help and support while I was writing my thesis! I also thank the Sensory Lab crew for setting up and running the longest and most involved taste panels. I thank all one hundred of my panelists for their participation and providing great data. I enjoyed watching all of your facial expressions, especially after tasting lemons and strawberries after the miracle fruit! Finally, I thank my family and friends for all of their support and encouragement - thank you for always being there for me! 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 7 LIST OF FIGURES .......................................................................................................... 8 LIST OF ABBREVIATIONS ............................................................................................. 9 ABSTRACT ................................................................................................................... 10 CHAPTER 1 INTRODUCTION .................................................................................................... 13 2 LITERATURE REVIEW .......................................................................................... 16 Flavor Perception .................................................................................................... 16 Odor Perception ...................................................................................................... 17 Taste Perception ..................................................................................................... 18 Determining Taste Status ....................................................................................... 19 Genetics of Taste .................................................................................................... 21 Bitter Taste Receptor ....................................................................................... 22 Sweet Taste Receptor ...................................................................................... 22 Sour Taste Receptor ........................................................................................ 23 Taste-Modifying Compounds .................................................................................. 23 Miracle Fruit ...................................................................................................... 24 Early studies .............................................................................................. 25 Mechanism ................................................................................................. 27 Recent research ......................................................................................... 29 Gymnema Sylvestre ......................................................................................... 30 Mechanism ................................................................................................. 31 Potential uses ............................................................................................ 32 Methods of Sensory Evaluation .............................................................................. 32 Category Scales ............................................................................................... 34 Direct Scaling Methods..................................................................................... 34 Labeled Scales ................................................................................................. 35 Labeled Magnitude Scale (LMS) ...................................................................... 36 General Labeled Magnitude Scale (gLMS) ....................................................... 37 3 RESEARCH METHODS AND MATERIALS ........................................................... 39 Panelist Recruitment ............................................................................................... 39 Taste-Modifying Compounds .................................................................................. 39 Food Selection ........................................................................................................ 40 5 Sensory Laboratory ................................................................................................ 41 Questionnaire Design ............................................................................................. 41 Training Session ..................................................................................................... 43 Study One ............................................................................................................... 44 Study Two ............................................................................................................... 45 Statistical Analysis .................................................................................................. 46 4 RESULTS AND DISCUSSION ............................................................................... 48 Study One ............................................................................................................... 50 Sour, but not Sweet .......................................................................................... 51 Sweet, but not Sour .......................................................................................... 55 Sweet and Sour ................................................................................................ 57 Not Sweet and not Sour ................................................................................... 59 Odor ................................................................................................................. 60 Taste and Overall Flavor Correlations .............................................................. 61 Strawberry .................................................................................................. 61 Lemon ........................................................................................................ 62 Maple syrup ............................................................................................... 62 Gender and Body Mass Index (BMI) ................................................................ 63 Study Two ............................................................................................................... 64 Sour, but not Sweet .......................................................................................... 65 Sweet, but not Sour .......................................................................................... 67 Sweet and Sour ................................................................................................ 68 Not Sweet and not Sour ................................................................................... 68 Gender and BMI ............................................................................................... 69 5 CONCLUSION ........................................................................................................ 92 APPENDIX A QUESTIONNAIRE .................................................................................................. 94 B IRB FORM .............................................................................................................. 95 C gLMS ...................................................................................................................... 96 D COMPUSENSE TEST BALLOT ............................................................................. 97 LIST OF REFERENCES ............................................................................................. 112 BIOGRAPHICAL SKETCH .......................................................................................... 117 6 LIST OF TABLES Table page 3-1 Food samples with typical taste associations and expected flavor changes. ..... 47 3-2 Demographic information of all panelists from study one and study two. ........... 47 4-1 Significant means differences for study one ....................................................... 70 4-2 Significant correlations for study one for selected food samples .......................