title: Monitoring the apple polyphenol oxidase-modulated adduct formation of phenolic and amino compounds.
abstract: Minimally processed fruit products such as smoothies are increasingly coming into demand. However, they are often combined with dairy ingredients. In this combination, phenolic compounds, polyphenoloxidases, and amino compounds could interact. In this work, a model approach is presented where apple serves as a source for a high polyphenoloxidase activity for modulating the reactions. The polyphenoloxidase activity ranged from 128 to 333nakt/mL in different apple varieties. From these, 'Braeburn' was found to provide the highest enzymatic activity. The formation and stability of resulting chromogenic conjugates was investigated. The results show that such adducts are not stable and possible degradation mechanisms leading to follow-up products formed are proposed. Finally, apple extracts were used to modify proteins and their functional properties characterized. There were retaining antioxidant properties inherent to phenolic compounds after adduct formation. Consequently, such interactions may also be utilized to improve the textural quality of food products.
authors.affiliation: Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany; Institute of Food Chemistry, Hamburg School of Food Science, University of Hamburg, Grindelallee 117, D-20146 Hamburg, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Reinkensmeier
authors.affiliation: Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany; BioAnalyt GmbH, Rheinstr. 17, D-14513 Teltow, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Steinbrenner
authors.affiliation: Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Homann
authors.affiliation: Leibniz Institute for Agricultural Engineering Potsdam-Bornim e.V., Department of Horticultural Engineering, Max-Eyth-Allee 100, D-14469 Potsdam, Germany.
authors.forename: Sara
authors.initials: S
authors.lastname: Bußler
authors.affiliation: Institute of Food Chemistry, Hamburg School of Food Science, University of Hamburg, Grindelallee 117, D-20146 Hamburg, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Rohn
authors.affiliation: Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany. Electronic address: rawel@uni-potsdam.de.
authors.forename: Hashadrai M
authors.initials: HM
authors.lastname: Rawel
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D005638:Fruit / Q000737:chemistry*; D027845:Malus / Q000737:chemistry*; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis*; D010936:Plant Extracts / Q000737:chemistry*; D011499:Protein Processing, Post-Translational / Q000502:physiology*
chemical_list: D000975:Antioxidants; D010636:Phenols; D010936:Plant Extracts
keywords: Apple polyphenoloxidase; Functionality; Phenol–amino-adducts; Post-translational protein modification