Analytik von Polyphenolen in Buntsäften im Hinblick auf Saftqualität, Farbe und antioxidative Aktivität (English shop)

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his dissertation investigates the composition, analytical characterization, and antioxidant activity of polyphenols in deeply colored fruit juices. Particular attention is given to anthocyanins, the natural pigments responsible for the red to purple coloration of many fruits, which are also of considerable interest in food chemistry due to their antioxidant properties. The study examines various fruit juices, including elderberry, cranberry, blackcurrant, sour cherry, blood orange, and aronia, as well as selected fruits. Advanced chromatographic and spectroscopic techniques, including high-speed countercurrent chromatography (HSCCC), HPLC-mass spectrometry, and LC-NMR spectroscopy, are employed to isolate, identify, and characterize polyphenolic compounds.

Another major focus is the influence of processing and storage on fruit juice color quality and antioxidant activity. The research examines changes in anthocyanin profiles, the formation of polymeric pigments, and copigmentation reactions that may enhance color intensity. The color activity concept is also applied to evaluate the contribution of individual anthocyanins to fruit juice coloration. The findings provide valuable insights into the relationships between polyphenol content, antioxidant activity, and juice quality, contributing to a better understanding of chemical changes occurring during storage.