Relevance of chromatographic efficiency in varietal authenticity verification of red wines based on their anthocyanin profiles: Interference of pyranoanthocyanins formed during wine ageing

The determination of the grape variety of aged red wines based on the ratio of acetylated and coumaroylated anthocyanins (Rac/coum) can be influenced by the formation of pyranoanthocyanins. Coelution of the pyranoanthocyanin pinotin A and the 3-coumaroylglucoside of malvidin can affect the obtained data for the Rac/coum values, which in turn could lead to a false classification of wine variety and rejection of the wines by the food authorities. Investigations using different reversed phase high performance liquid chromatography columns demonstrate the importance of a good chromatographic resolution of these analytes.