Anthocyanin Color Level in Port-Type Wines as Affected by the use of Wine Spirits Containing Aldehydes

The presence of heads in wine spirits used in the production of red sweet (porttype) wines produced an enhancement of the red pigmentation, measured 2-3 months after production. Other chemical and sensory effects are also reported. These effects all correlate with the volatile aldehyde content of the added heads. On longer storage, differences between samples prepared with and without aldehydic spirits diminished but did not disappear entirely. The results suggest that the anthocyanin pigments are modified to form more adsorbable, less reactive, presumably larger, but still red products. A possible mechanism to explain these effects is discussed, namely the Baeyer reaction between phenols and aldehydes in acidic solution.