Changes in the Anthocyanins, Flavonoids and Hydroxycinnamic Acid Esters during Fermentation and Aging of Merlot and Cabernet Sauvignon

Abstract

High-performance liquid chromatography (HPLC) was used to measure changes in the hydroxycinnamic acid-tartaric acid esters, anthocyanins, catechins and other 280-nm absorbing compounds during the vinification and aging of Merlot and Cabernet Sauvignon. The caffeoyl and p-coumaroyl tartrate ester concentrations decreased markedly during fermentation with only minor losses during aging. Anthocyanin concentration increased to a maximum by the third day and decreased thereafter such that by 240 days less than 10% of the original amount remained. Catechin contents of both varieties were similar, reaching a maximum by the fourth day and decreasing slowly with age. The epicatechin content of Merlot was significantly greater than with Cabernet Sauvignon. It also decreased during aging. However, the total catechin loss was only about ¼ that of the loss of anthocyanins. A large number of compounds absorbing at 280 nm were separated by HPLC and their changes followed during aging. Some are undoubtedly flavonols, but have not yet been identified.