Analytical characterization and the impact of ageing on anthocyanin composition and degradation in juices from five sour cherry cultivars

Five different sour cherry cultivars were processed to sour cherry juices in order to analyze their composition and the impact of storage on anthocyanin composition. Regarding primary juice parameters all cultivars showed high dry masses (13.8–17.2° Brix) and sugar free extracts (59.4–74.3 g/L). Anthocyanins were identified as cyanidin-3-(2^G-glucosylrutinoside), cyanidin-3-(2^G-xylosylrutinoside), cyanidin-3-sophoroside, cyanidin-3-glucoside, cyanidin-3-rutinoside, and peonidin-3-rutinoside. Besides the original anthocyanins, 5-carboxypyrano-anthocyanins occurred as new reaction products during storage. HPLC-MSⁿ experiments revealed, that a further ageing pigment was probably resulting from the reaction of an original anthocyanin with acetaldehyde. A significant decline of the original anthocyanin concentrations could be observed (70–75%) during 6 months of storage at 20 °C. Degradation kinetics of anthocyanins were calculated taking the reaction rate as first order. Colourless polyphenol concentrations and antioxidant capacities (TEAC) of the juices were not affected during storage.