Secondary wine pigments

Since it appears that anthocyanins and tannins condense in wine to form secondary wine pigments, the nature of the linkage between these compounds has been the focus of many investigations. There are a large number of possibilities but this chapter will discuss only two for historical purposes. Others will be discussed by other authors in this book. Based upon the structure of a natural compound, Jurd synthesized a dimer from catechin and a synthetic anthocyanidin (Figure 1). The flavylium form of the anthocyanidin has an electrophilic carbon at C-4 that will condense with the phloroglucinol ring of catechin. The new product, a flavene, will be oxidized by a second flavylium... 

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