Changes in phenolic compounds during accelerated browning in white wines from cv. Pedro Ximenez and cv. Baladi grapes

Changes in absorbance (A420, A280) and phenolic compounds during browning of white wines from cv. Pedro Ximenez and cv. Baladi grapes were studied. Bottled wines were stored at 50 °C for 12 weeks, after which they were uncorked from the 12th to 14th week. Samples in triplicate were collected after 4, 12 and 14 weeks as well as the initial sample. A420 showed no differential susceptibility to browning for the two wines, but there were higher A280 values and phenolic compound contents in the initial samples of Pedro Ximenez wine. Caftaric and coutaric acids as well as procyanidins were the compounds showing greatest differences between the wines of the two varieties studied. Monomeric and dimeric flavan-3-ol derivatives also changed.