Application of Rice Bran Wax Organogel to Substitute Solid
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APPLICATION OF RICE BRAN WAX ORGANOGEL TO SUBSTITUTE SOLID FAT AND ENHANCE UNSATURATED FAT CONTENT IN ICE CREAM by Daniele Cristina Zulim Botega A Thesis Presented to The University of Guelph In partial fulfillment of requirements for the degree of Master of Science in Food Science Guelph, Ontario, Canada © Daniele C. Zulim Botega, January, 2012 ABSTRACT APPLICATION OF RICE BRAN WAX ORGANOGEL TO SUBSTITUTE SOLID FAT AND ENHANCE UNSATURATED FAT CONTENT IN ICE CREAM Daniele C. Zulim Botega Advisor: Professor H. D. Goff, Dr. University of Guelph, 2012 Co-Advisor: Professor A. Marangoni, Dr. The objective of this study was to investigate the potential application of rice bran wax (RBW) organogel to replace solid fat content and create the fat network in ice cream. Ice creams with 10% fat or 15% fat were formulated with RBW organogel as the fat source, and two different emulsifiers were used: polmo, a commercial blend of emulsifiers which contains 80% mono- and diglycerides and 20% polysorbate 80, and Glycerol monooleate (GMO). Candelilla wax (CDW) organogel and carnauba wax (CBW) organogel were also tested for comparison. RBW organogel had the ability to form and sustain structure in 15% fat ice creams when GMO was used as the emulsifier. Transmission electron microscopy revealed that the RBW crystal morphology within the fat droplet, when GMO was used as the emulsifier, was characterized by the growth of crystals at the outer edge of the droplet which increased fat destabilization and network formation. ACKNOWLEDGEMENTS I would like to express my sincere appreciation to my advisor Dr. Douglas Goff for granting me the opportunity to undertake this intriguing project. Thanks for your time, patience, persistent help, and especially for your guidance, which made this a successful research project. My special gratitude also goes to my co-advisor Dr. Alejandro Marangoni for the opportunity to extend my knowledge in the field of Food Science when you first invited me to come to Canada and work in your laboratory as a graduate student. Your support and advice were fundamental to the development of this project. It has been an honour to work with both of you. Appreciation is expressed to Nestlé Product Technology Centre, France, for financial support. I am also deeply indebted to the research associates of Nestlé, Max Puaud and Virginie DeBoishebert. Despite the distance, they have been directly involved in the development of this thesis providing valuable assistance, which was important to the preparation and completion of this project. I would like to thank Dr. Sandy Smith for dedicating her time in the development of this thesis. You have made my experience with electron microscopy an educational time, but most important a time full of pleasant and enjoyable memories. Your knowledge and assistance made a huge contribution to the success of this work and your friendship was a valuable contribution to my personal growth. Your assistance was priceless. My sincere thanks go to all my family members, friends and lab mates for the encouragement, support and care. A special thanks to Elise Ringgenberg, Edmund Co, iii Edita Verespej, Fernanda Svaikauskas, Nuria Acevedo, Majid Hassas Roudsari and Saeed Mirzaee Ghazani for the advice, technical help, but most especially for the friendship shared during these years. My gratitude also goes to Natasha, Samantha and Linda Dowling. I want to thank you for sharing, listening and supporting me during my good and bad moments during this time. I appreciate all of your loving support. Our friendship is irreplaceable. I own my deepest gratitude for my loving and supportive boyfriend, Thiago. From the bottom of my heart, I thank you for the encouragement and especially your patience dedicated throughout my Master’s program. Your presence and support was fundamental during this time. I finish my acknowledgements dedicating this thesis to the most important people in my life, my parents Sebastião and Neide, and my sister Eloise. Thank you for the support you gave me even when I made decisions that afflicted you negatively. Thank you for the care you dedicated to me even though we are far apart. But what I would like to thank you for most is your love that made me tolerate and endure the most difficult times of this experience. I would not accomplish this stage of my life without you. iv TABLE OF CONTENTS Acknowledgements ............................................................................................................... iii Table of Contents ................................................................................................................... v List of Tables ........................................................................................................................ ix List of Figures ....................................................................................................................... xi List of Abreviations .......................................................................................................... xviii 1. INTRODUCTION .......................................................................................................... 1 2. LITERATURE REVIEW .............................................................................................. 7 2.1. Ice Cream .............................................................................................................. 7 2.1.1. Fat Sources ....................................................................................................... 7 2.1.1.1. Milk Fat ..................................................................................................... 8 2.1.1.2. Vegetable Fats ........................................................................................... 9 2.1.2. Ice Cream Processing - Structure Development ............................................ 13 2.1.2.1. Mix Preparation ...................................................................................... 13 2.1.2.2. Aging....................................................................................................... 15 2.1.2.3. Freezing................................................................................................... 18 2.1.2.3.1. Destabilization of Fat ....................................................................... 19 2.1.2.3.2. Air Incorporation ............................................................................. 22 2.1.2.4. Hardening ................................................................................................ 22 2.1.3. Some Ice Cream Structural Components ....................................................... 23 2.1.3.1. Air Cells .................................................................................................. 23 2.1.3.2. Fat Droplets ............................................................................................. 24 2.2. Organogels .......................................................................................................... 26 2.2.1. Applications ................................................................................................... 29 2.2.2. Some Classes of Organogelators Suitable for Food Application ................... 29 2.2.2.1. Fatty Acids .............................................................................................. 29 2.2.2.2. Fatty Alcohols ......................................................................................... 30 2.2.2.3. Monoglyceride ........................................................................................ 31 2.2.2.4. Wax Esters .............................................................................................. 32 2.2.3. Waxes ............................................................................................................. 33 2.2.3.1. Rice Bran Wax ........................................................................................ 35 v 2.2.3.2. Candelilla Wax........................................................................................ 39 2.2.3.3. Carnauba Wax ......................................................................................... 40 2.3. Ice Cream Structure Characterization ................................................................. 41 2.3.1. Standard Methods .......................................................................................... 41 2.3.1.1. Overrun ................................................................................................... 41 2.3.1.2. Meltdown rate ......................................................................................... 42 2.3.1.3. Light Scattering ....................................................................................... 43 2.3.1.4. Differential Scanning Calorimetry .......................................................... 45 2.3.1.5. Protein Analysis ...................................................................................... 46 2.3.2. Microstructure Characterization .................................................................... 47 2.3.2.1. Cryo-Scanning Electron Microscopy ...................................................... 48 2.3.2.2. Transmission Electron Microscopy ........................................................ 49 2.3.2.3. Image Analysis........................................................................................ 50 3. MATERIALS AND METHODS ................................................................................ 52 3.1. Organogel ..........................................................................................................