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Berry phenolics: isolation, analysis, identification, and antioxidant properties Petri Kylli ACADEMIC DISSERTATION To be presented, with the permission of the Faculty of Agriculture and Forestry of the University of Helsinki, for public criticism in lecture hall B2, Viikki, on August 26th 2011, at 12 o’clock noon. University of Helsinki Department of Food and Environmental Sciences Food Chemistry Helsinki 2011 Custos: Professor Vieno Piironen Department of Food and Environmental Sciences U
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  Berry phenolics: isolation, analysis, identication, and antioxidant properties Petri Kylli ACADEMIC DISSERTATION To be presented, with the permission of the Faculty of Agriculture and Forestry ofthe University of Helsinki, for public criticism in lecture hall B2, Viikki, on August 26 th  2011, at 12 o’clock noon.University of HelsinkiDepartment of Food and Environmental SciencesFood ChemistryHelsinki 2011  Custos: Professor Vieno PiironenDepartment of Food and Environmental SciencesUniversity of HelsinkiHelsinki, FinlandSupervisor: Professor Marina HeinonenDepartment of Food and Environmental SciencesUniversity of HelsinkiHelsinki, FinlandReviewers: Ph.D. Pirjo MattilaMTT Agrifood Research FinlandJokioinen, FinlandPh.D. Claudine ManachINRA, Nutrition HumaineSaint-Genes-Champanelle, FranceOpponent: Professor Anne S. MeyerDepartment of Chemical and Biochemical EngineeringTechnical University of DenmarkKgs. Lyngby, DenmarkISBN 978-952-10-7114-0 (paperback) ISBN 978-952-10-7115-7 (pdf;) ISSN 0355-1180Cover picture: Tuuli Koivumäki Unigraa Helsinki 2011  Kylli, P 2011. Berry phenolics: isolation, analysis, identication, and antioxidant properties (dissertation). EKT-series 1502. University of Helsinki. Department of Food and EnvironmentalSciences. 90+62 pp. ABSTRACT The main objectives in this thesis were to isolate and identify the phenolic compounds inwild ( Sorbus aucuparia ) and cultivated rowanberries, European cranberries ( Vacciniummicrocarpon ), lingonberries ( Vaccinium vitis-idaea ), and cloudberries (  Rubus chamaemorus ), as well as to investigate the antioxidant activity of phenolics occurring in berries in foodoxidation models. In addition, the storage stability of cloudberry ellagitannin isolate was studied. In wild and cultivated rowanberries, the main phenolic compounds were chlorogenic acids and neochlorogenic acids with increasing anthocyanin content depending on the crossing partners.The proanthocyanidin contents of cranberries and lingonberries were investigated, revealingthat the lingonberry contained more rare A-type dimers than the European cranberry. The liquidchromatography mass spectrometry (LC-MS) analysis of cloudberry ellagitannins showed thattrimeric lambertianin C and sanguiin H-10 were the main ellagitannins. The berries, rich in different types of phenolic compounds including hydroxycinnamic acids, proanthocyanidins, and ellagitannins, showed antioxidant activity toward lipid oxidation inliposome and emulsion oxidation models. All the different rowanberry cultivars preventedlipid oxidation in the same way, in spite of the differences in their phenolic composition. Interms of liposomes, rowanberries were slightly more effective antioxidants than cranberry and lingonberry phenolics. Greater differences were found when comparing proanthocyanidinfractions. Proanthocyanidin dimers and trimers of both cranberries and lingonberries were most potent in inhibiting lipid oxidation.Antioxidant activities and antiradical capacities were also studied with hydroxycinnamic acidglycosides. The sinapic acid derivatives of the hydroxycinnamic acid glycosides were the mosteffective at preventing lipid oxidation in emulsions and liposomes and scavenging radicals in DPPH ã assay. In liposomes and emulsions, the formation of the secondary oxidation product,hexanal, was inhibited more than that of the primary oxidation product, conjugated dienehydroperoxides, by hydroxycinnamic acid derivatives. This indicates that they are principallychain-breaking antioxidants rather than metal chelators, although they possess chelating activity as well.The storage stability test of cloudberry ellagitannins was performed by storing ellagitannin isolate and ellagitannins encapsulated with maltodextrin at different relative vapor pressures. The storage stability was enhanced by the encapsulation when higher molecular weight maltodextrin was used. The best preservation was achieved when the capsules were storedat 0 or 33% relative vapor pressures. In addition, the antioxidant activities of encapsulatedcloudberry extracts were followed during the storage period. Different storage conditions didnot alter the antioxidant activity, even though changes in the ellagitannin contents were seen.The current results may be of use in improving the oxidative stability of food products by using berries as natural antioxidants.  ACKNOWLEDGEMENTS This study was carried out at the Department of Food and Environmental Sciences, FoodChemistry Division, at the University of Helsinki during the years 2005-2011. The work wasfunded by The Finnish Graduate School on Applied Bioscience, The University of HelsinkiFunds, The National Technology Agency (TEKES), and The Finnish Cultural Foundation. Their nancial support is gratefully acknowledged.I wish to express my deepest gratitude to Professor Marina Heinonen, supervisor of the work,for giving me the chance to work in this exciting eld of berries and phenolic compounds. I thank her for her great support and advice throughout these years. I am grateful to the reviewers Dr. Pirjo Mattila and Dr. Claudine Manach for their constructive comments, and careful and thorough review of the thesis. I wish to thank Prof. Vieno Piironen for introducing me to the fascinating world of foodchemistry. My sincere thanks go to docent Velimatti Ollilainen for the guidance and supportwith LC-MS and docent Anna-Maija Lampi for the support in the lab. I wish to thank allmy present and former colleagues and coworkers in D-building. Especially I wish to thank  Minnamari Edelmann, Mario Estévez, Göker Gürbüz, Kirsti Herttua, Tuuli Koivumäki, Hanna Komu, Mari Lehtonen, and Miikka Olin for their assistance and enjoyable collaboration. Prof. Maija Tenkanen, Prof. Kirsi Jouppila, M.Sc. Pia Laine, Dr. Riitta Puupponen-Pimiä, Dr.Liisa Nohynek, Dr. Benita Westerlund-Wikström, M.Sc. Paula Nousiainen, Dr. Jussi Sipilä,Dr. Tiina Leppänen, and Prof. Eeva Moilanen are acknowledged for giving valuable adviceand acting as co-authors. A part of this work was done in Scotland at Scottish Crop Research Institute. I wish to thank Dr. Derek Stewart and Dr. Gordon McDougall for giving me the opportunity to visit your laboratory. My warm thanks I owe to my friends for giving me many joyful and unforgettable moments.Finally, I wish to thank my parents, sisters and brother for their interest and encouragement. Helsinki, July 2011Petri Kylli
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