1 Author: Avila, Johana Maria Title: Effect of Roasting on the Physicochemical, Textural, Rheological and Sensory Properties of Five Varieties of Honduras Grown Coffee Beans and Brewed Coffee The accompanying research report is submitted to the University of Wisconsin-Stout, Graduate School in partial completion of the requirements for the Graduate Degree/ Major: MS in Food and Nutritional Science Research Advisor: Pranabendu Mitra, PhD, P. Eng. Submission Term/Year: Fall 2019 Number of Pages: 63 Style Manual Used: American Psychological Association, 6th edition I have adhered to the Graduate School Research Guide and have proofread my work. I understand that this research report must be officially approved by the Graduate School. Additionally, by signing and submitting this form, I (the author(s) or copyright owner) grant the University of Wisconsin-Stout the non-exclusive right to reproduce, translate, and/or distribute this submission (including abstract) worldwide in print and electronic format and in any medium, including but not limited to audio or video. If my research includes proprietary information, an agreement has been made between myself, the company, and the University to submit a thesis that meets course-specific learning outcomes and CAN be published. There will be no exceptions to this permission. I attest that the research report is my original work (that any copyrightable materials have been used with the permission of the original authors), and as such, it is automatically protected by the laws, rules, and regulations of the U.S. Copyright Office. My research advisor has approved the content and quality of this paper. STUDENT: NAME: Johana Maria Avila DATE: 12/19/2019 ADVISOR: (Committee Chair if MS Plan A or EdS Thesis or Field Project/Problem): NAME: Pranabendu Mitra DATE: 12/19/2019 --------------------------------------------------------------------------------------------------------------------- This section to be completed by the Graduate School This final research report has been approved by the Graduate School. Director, Office of Graduate Studies: DATE: 2 Avila, Johana M. Effect of Roasting on the Physicochemical, Textural, Rheological and Sensory Properties of Five Varieties of Honduras Grown Coffee Beans and Brewed Coffee Abstract The main objective of this study was to identify the commercial feasibility of five varieties of coffee beans (Pacamara, Parainema, Lempira, Obata Marsellesa) grown in Honduras by comparing with two commercial samples for their physicochemical, rheological and sensory properties. The green coffee beans were roasted at 200℃ for 45 min using a conventional oven. The physicochemical properties of coffee beans were determined before and after roasting and compared with commercial light roasted and dark roasted coffee beans. The sensory, physicochemical and rheological properties of brewed coffee were determined to identify the preferred varieties of coffee. The ANOVA showed that the roasting process affected the quality of coffee beans significantly (p<0.05). The moisture content (8-9%) and water activity (0.3-0.4) of roasted beans improved the shelf-life as self-stable coffee. The sensory analysis indicated that there was a significant difference between Lempira and Parainema varieties. The overall results of this study indicated the physicochemical, rheological and sensory properties of five varieties of Honduras grown coffees were very comparable with the commercial tested samples. The study is expected to be helpful to open a new window for the coffee business using Honduras grown tested coffees. 3 Acknowledgments Thanks God that always enlightens us and opens paths. I thank my advisor Dr. Pranabendu Mitra for his constant guidance and help, especially for his methodological orientation and for his continued encouragement throughout the process until the end of it. I would like to give a special thank to Dr. Eun Joo Lee, Department Chair of the Food and Nutrition Department, who generously coordinated with Graduate School for my exception application to be eligible to continue my study after a break. I am thankful to Dr Cynthia Rohrer, Program Director for providing the logistic in the laboratory for the sensory analysis test. I thank the students and professors for their willingness to participate for the completion of the sensory test. My heartfelt deep thanks to my parents, sibling, my husband for their constant patience and support that they always demonstrated. I thank all those people who directly or indirectly contributed to this research work could be carried out. Thanks to all the coffee farmer for their hard work. Thanks to the sponsors of this research. This was funded by Green-Field Food & Ingredients (Honduras & USA). Also, the research was partially funded by the Advisor’s Maybelle Ranney Price Professorship (CEHHHS-GM-00295-1-A-20) professional development grant, University of Wisconsin-Stout. 4 Table of Contents Abstract ...................................................................................................................................... 2 List of Tables .............................................................................................................................. 7 List of Figures ............................................................................................................................. 8 Chapter I: Introduction ................................................................................................................ 9 Statement of the Problem ............................................................................................... 11 Purpose of the Study ...................................................................................................... 11 Assumptions of the Study .............................................................................................. 11 Limitations of the Study ................................................................................................ 12 Methodology ................................................................................................................. 12 Chapter II: Literature Review .................................................................................................... 13 Origin of the Coffee ....................................................................................................... 13 History of the Coffee in Honduras ...................................................................... 14 Quality of the Coffee ..................................................................................................... 15 Quality of the Brewed Coffee ............................................................................. 15 Proper Management of the Crop ......................................................................... 16 Proper Management in the Processing ................................................................ 16 Evaluation and Cupping of the Samples ......................................................................... 18 Sensory Properties ............................................................................................. 18 Physical and Chemical Properties ....................................................................... 18 Main Defects in Coffee, Most Common Causes and How to Avoid Them ..................... 19 Rough or Astringent ........................................................................................... 20 Terrosa ............................................................................................................... 20 5 Mohosa .............................................................................................................. 20 Flavor to River (Iodine)...................................................................................... 21 Fructose ............................................................................................................. 21 Vinous ............................................................................................................... 22 Chapter III: Methodology .......................................................................................................... 23 Materials ....................................................................................................................... 23 Instrumentation.............................................................................................................. 24 Data Collection Procedures ............................................................................................ 24 Quality Characterization of Coffee Beans and Brewed Coffee ....................................... 26 Determination of Bulk Density, Piece Density, Solid Density ............................ 26 Determination of Rehydration Capacity of Green Coffee Bean and Roasted Coffee Bean............................................................................................ 27 Determination of Percent of Porosity.................................................................. 27 Determination of Water Activity (aw) ................................................................ 27 Determination of Moisture Content .................................................................... 27 Determination of the Color ................................................................................. 28 Determination of Brix ........................................................................................ 28 Determination of pH