ANTIOXIDANT CAPACITY, PHENOLIC AND VOLATILE COMPOUND COMPOSITION OF BLACKBERRY WINES PRODUCED USING KOREAN TRADITIONAL WINEMAKING TECHNIQUES By YOURI JOH Bachelor of Science in Human Nutrition & Food Science New Mexico State University Las Cruces, NM 2007 Master of Science in Food Science Oklahoma State University Stillwater, OK 2010 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY July, 2014 ANTIOXIDANT CAPACITY, PHENOLIC AND VOLATILE COMPOUND COMPOSITION OF BLACKBERRY WINES PRODUCED USING KOREAN TRADITIONAL WINEMAKING TECHNIQUES Dissertation Approved: Dr. William G. McGlynn Dissertation Adviser Dr. Niels O. Maness Dr. Mike W. Smith Dr. Tim Bowser ii ACKNOWLEDGEMENTS I offer a special thank you to my academic advisor Dr. William McGlynn who provides me good guidance, encouragement and support throughout my graduate life here in Stillwater. For my committee members, thank you all for sharing your knowledge and experience with me. I would like to say thank you to Dr. Niels Maness who helped me to expand my research as well as to learn fat extraction and volatile analysis. For Dr. Mike Smith and Dr. Tim Bowser, thank you for provide me good feedback about my research. In addition, I would like to say thank you to Dr. Mark Payton who provided me guidance and support in statistical analyses. Furthermore, I would like to say thank you to Becky Carroll who helped me to collect blackberries in the hot and dry summer in Oklahoma. Also, thank you to Adrian Nault, Erni Murtini, Pavalee Chompoorat, Ban Alkeen, Maggie Hartung, Alex Upsaw and many others who helped me to harvest blackberries during the hot summer. It was great pleasure to work in the field and provided me good memories with them. In addition, I would like to say thank you to Darren Scott, Veneta Banskalieva, Angie Lathrop, and Dr. Guadalupe Davila El-Rassi for analytical help, troubleshooting and support. Without them I would have had a hard time expanding my research and might have lost the chance to learn new methods and equipment. Also, thank you to Jacob Nelson for providing me space to store blackberry wine, and also for making me laugh with good jokes. Thank you to my friends Elif Kalkan, Neha Thunga, Meizhen Xi, Eechin Ng and other graduate students for great support and being good entertainers. Lastly, I greatly appreciate my parents and brothers who always listen my worries, offer me encouragement, and serve as good mentors, which helped me to concentrate on my work. iii Acknowledgements reflect the views of the author and are not endorsed by committee members or Oklahoma State University. Name: Youri Joh Date of Degree: July, 2014 Title of Study: ANTIOXIDANT CAPACITY, PHENOLIC AND VOLATILE COMPOUND COMPOSITION OF BLACKBERRY WINES PRODUCED USING KOREAN TRADITIONAL WINEMAKING TECHNIQUES Major Field: Food Science Abstract: This research project was designed to evaluate the winemaking potential of ‘Natchez’ and ‘Triple Crown’ blackberries grown in Oklahoma as well as to examine the measurable basic physical properties and potential health-benefits of phenolic compounds in blackberry wines made using traditional Korean winemaking techniques with variations in fermentation temperature (21.6 °C vs. 26.6 °C), and fermentation type (yeast inoculation vs. wild-type fermentation). Korean traditional wine processing methods, which typically employ wild-type microorganisms for fermentation, may provide different types and levels of health-related compounds than common wine production methods. The pH, titratable acidity, soluble solids, and percent alcohol of blackberry juice and wine samples were measured as basic physical properties. The Harbertson-Adams assay, oxygen radical absorbance capacity (ORAC), high performance liquid chromatography (HPLC), and gas chromatography (GC) of blackberry juice and wine samples were investigated as indicators of health benefits of phenolic compounds, primarily antioxidant potential. Total percent fat of whole blackberries and pomace was also analyzed. Among physical properties, ‘Triple Crown’ wines made at the higher fermentation temperature were sweeter and had higher alcohol concentrations than ‘Natchez’ wines. ‘Natchez’ berries had higher percent total fat than ‘Triple Crown’ berries. ‘Natchez’ juices and wines generally had higher concentrations of total phenolics, tannins, and anthocyanins while ‘Triple Crown’ juices and wines generally had higher concentrations of polymeric pigments, phenolic acids, and free volatile compounds. ‘Triple Crown’ wines also generally exhibited higher antioxidant activity. Examining the two fermentation temperatures, 26.6 °C increased the initial concentration of phenolics in the wines. However, wines fermented at 21.6 °C showed less loss of phenolics during aging. Between two fermentation types, wild-type fermentation had higher phenolic concentrations than yeast inoculated wines. Overall, the traditional Korean winemaking technique examined in this study provided good production and retention of phenolic compound and volatile aroma compounds in the wines and that the wines produced were high in antioxidant capacity. iv TABLE OF CONTENTS Chapter Page I. INTRODUCTION .......................................................................................................... 1 Study goals and objectives ...................................................................................... 4 References .............................................................................................................. 6 II. REVIEW OF LITERATURES .......................................................................................... 8 History of blackberry cultivation............................................................................. 8 Plant cycle of blackberries ...................................................................................... 9 Types of blackberries .............................................................................................. 9 Blackberry production .......................................................................................... 10 Harvesting blackberries ........................................................................................ 11 Blackberry quality attributes ................................................................................ 12 Blackberry aroma and volatiles ............................................................................ 13 Plant phenolics: Types and their functions ........................................................... 14 Important properties of anthocyanins ................................................................. 17 Anthocyanins in blackberries ................................................................................ 21 Antioxidant activity of polyphenolic compounds ................................................. 23 Measuring antioxidant activity ............................................................................. 24 Health benefits of polyphenols ............................................................................. 25 Antioxidant activity and other health benefits of blackberries ............................ 27 Effect of blackberry processing on potential health benefits .............................. 29 Potential health benefits of berry seed oil ........................................................... 30 Effect of fruit fermentation on potential fruit health benefits ............................ 31 Korean fermented drink ....................................................................................... 32 Korean earthenware jars and their breathability ................................................. 33 References ............................................................................................................ 36 III. MATERIALS AND METHODS ................................................................................... 42 Berry collection and storage ................................................................................. 42 Physical properties for whole blackberry juice and wine ..................................... 43 General physical properties of whole blackberries ........................................ 43 v Chapter Page Preparation of juice samples .......................................................................... 43 pH .................................................................................................................... 44 Soluble solids .................................................................................................. 44 Titratable acidity ............................................................................................. 44 Percent alcohol ............................................................................................... 45 Sulfur dioxide test ........................................................................................... 45 Korean traditional blackberry wine making process ............................................ 47 Sample preparation ........................................................................................ 47 Wine processing .............................................................................................. 48 Fermentation .................................................................................................. 50 Ageing wine ....................................................................................................