Dadmun Cornell 0058O 11029.Pdf (1.396Mb)
Total Page:16
File Type:pdf, Size:1020Kb
EFFECT OF SUN EXPOSURE ON THE EVOLUTION AND DISTRIBUTION OF ANTHOCYANINS IN INTERSPECIFIC RED HYBRID WINEGRAPES A Thesis Presented to the Faculty of the Graduate School of Cornell University in Partial Fulfillment of the Requirements for the Degree of Master of Science by Catherine Hope Dadmun August 2020 © 2020 Catherine Hope Dadmun ABSTRACT Interspecific hybrid winegrapes are economically important in areas where environmental pressures inhibit traditional Vitis vinifera production. To clarify the effect of vine microclimate on red hybrid wine color, skin extract anthocyanins were characterized via HPLC for shaded and unshaded fruit from three economically significant cool-climate hybrid cultivars (Vitis spp): Corot noir, Maréchal Foch, and Marquette. Light exposure and berry and air temperature were monitored in Corot noir to represent generalized vine microclimate. Across all cultivars, the samples that underwent the leaf-pulling treatment (exposed samples) did not have significantly different concentrations of total anthocyanins compared to the control (shaded samples). However, certain individual anthocyanins within each cultivar demonstrated different concentrations with the exposure treatment. This work is the first step in defining the evolution of anthocyanin profiles during interspecific hybrid grape ripening to allow cool- climate wine grape growers to optimize viticultural production methods for high-quality red hybrid wines. Keywords: anthocyanin, interspecific hybrid, ripening, sunlight exposure, viticultural practice, leaf removal BIOGRAPHICAL SKETCH Catherine Dadmun joined Anna Katharine Mansfield’s group in the Department of Food Science and Technology at Cornell University in August 2018. She studies grape and wine chemistry, primarily focusing on hybrid Vitis spp. and the chemical color composition of grapes. Beyond academics, Catherine was heavily involved in the Food Science Graduate Student Organization (FSGSO), the Graduate and Professional Women’s Network (GPWomeN), and tutoring students at Beverly J. Martin Elementary School and later virtually through Weill Cornell Tutors. She served as a member of the Social Committee for FSGSO and the Communications Chair for GPWomeN. Prior to her graduate studies, Catherine received her B.S. in Chemistry and B.A. in French and Francophone Studies from the College of Charleston in Charleston, South Carolina. She participated in a Chemistry Undergraduate Research Program funded by the National Science Foundation at Virginia Tech over the summer of 2017, where her work in Susan Duncan’s Lab introduced her to Food Science. Upon completion of her Master’s in Science, Catherine will be continuing to study the chemistry of grapes and wine in Anna Katharine Mansfield’s lab at Cornell University for her Ph.D. and hopes to become even further involved in science communication and Extension. iii To my parents, Mark and Jayne Dadmun, who taught me to think critically, question everything, and find passion in everything I do. iv ACKNOWLEDGMENTS I would like to acknowledge Prejean Winery, Stever Hill Vineyards, and the Finger Lakes Teaching and Demonstration Vineyard for their generous donation of grape samples and The Cornell Agritech Venture Grant for funding this research. I’d also like to thank Don Caldwell, who did all of the hard work leaf-pulling, monitored the vineyards, and helped with sample collection. I am so thankful for my advisor, Dr. Anna Katharine Mansfield. Thank you for welcoming me into your lab with open arms and not only being an academic advisor, but a true mentor. Thank you for listening to my many questions and ideas with an open mind and responding truthfully from your wealth of knowledge and experience. Thank you for your support and trust in my ambitions, flexibility, genuine kindness, adventures in Italy, recipe exchanges, and laughter over Zoom calls. I look forward for more to come. I’d also like to thank my Committee member, Dr. Gavin L. Sacks, for his patience, open door, and inquisitive interest in any question I could bring his way. Your wisdom and advice, in addition to your invaluable class, have been crucial in the progression of my studies and my understanding of wine chemistry. I want to acknowledge Dwayne Bershaw and Patrick Gibney, the two of whom inspired me by their passion in the classes they taught. Not only did I learn an expanse of knowledge from their expertise, but I am extremely grateful for their commitment to finding new ways to ensure the understanding of their students, their sense of humor, and the amount of hard work they put into their teaching. I’d also like to thank Erin Atkins, whose door was always open and v whose face was always smiling. She is an invaluable member of the Food Science and Technology Graduate Program and her endless hard work should never go unnoticed. Of course, I’d like to thank Demi Perry, who began as my lab technician and manager and after transitioning out of that position into a full-time graduate student, became purely a friend and mentor. Thank you for your patience, honest criticism, wisdom, response to my late- night HPLC questions (even after you were no longer working in my lab), 80’s dance parties as we packed up the lab, and sunny adventures. Who knows where I would be without you. I’d also like to extend the deepest gratitude to my family, whose unconditional support in any and every way has given me the confidence and security to pursue my ambitions: my mom and dad, Jayne and Mark Dadmun, whose rock-solid support and love has never once wavered, and to my sister and brothers, Maggie, Ryan, and Ben, who keep me smiling and inspired to the be the best I can be. I also need to thank my friends here in Ithaca, in the department and beyond, who have formed an unbreakable network of supportive, smiling, resilient confidants. I’m glad we’re on this journey together. Finally, I want to thank Dr. John Turner, who explained the chemistry of the crème brûlée we were making in Oxford when I was 14. I didn’t know it then, but your passion for food chemistry was contagious. vi TABLE OF CONTENTS Biographical Sketch................................................................................................................... iii Acknowledgements .................................................................................................................... v List of Figures............................................................................................................................ ix List of Tables ............................................................................................................................. xi CHAPTER 1: LITERATURE REVIEW 1 I. Anthocyanin Chemistry .................................................................................................. 1 II. Interspecific Hybrid Grape Cultivars ........................................................................... 19 III. Anthocyanins and Wine Quality .................................................................................. 29 IV. Unique Qualities of Anthocyanins in Hybrid Grapes ................................................... 32 V. Viticultural and Winemaking Practices: Influence on Anthocyanins .......................... 35 VI. References .................................................................................................................... 42 CHAPTER 2: EFFECT OF SUN EXPOSURE ON THE EVOLUTION AND DISTRIBUTION OF ANTHOCYANINS IN INTERSPECIFIC RED HYBRID WINEGRAPES 61 I. Introduction .................................................................................................................. 61 II. Materials and Methods ................................................................................................. 64 a. Sample Collection ............................................................................................ 64 b. Solvents and Instrumentation ........................................................................... 65 c. Counting and Weighing Samples ..................................................................... 66 d. Separating Skin from Pulp................................................................................ 66 e. Freeze-Drying Skins ......................................................................................... 66 f. Grinding Skins .................................................................................................. 67 g. Methanol Extraction ......................................................................................... 67 h. Solid-Phase Extraction ..................................................................................... 68 i. HPLC Analysis ................................................................................................. 69 j. Statistical Analysis ........................................................................................... 69 III. Results .......................................................................................................................... 70 a. Corot noir.......................................................................................................... 70 b. Maréchal Foch .................................................................................................. 79 c. Marquette .......................................................................................................... 87 d. Viticulture ........................................................................................................