Investigations on Anthocyanins in Wines from <i>Vitis vinifera</i> cv. Pinotage: Factors Influencing the Formation of Pinotin A and Its Correlation with Wine Age
Michael Schwarz, Glenn Hofmann, Peter Winterhalter
Journal of Agricultural and Food Chemistry
Abstract
Pinotage red wines were found to contain a reaction product of malvidin 3-glucoside and caffeic acid, the so-called pinotin A. A total of 50 Pinotage wines from the vintages 1996-2002 were analyzed for the content of pinotin A, malvidin 3-glucoside, caffeic acid, and caftaric acid. Statistical analyses were performed to reveal variations in the content of these compounds and to determine the factors that influence pinotin A formation during wine aging. An exponential increase of the concentration of this aging product was observed with prolonged storage time. The most rapid synthesis of pinotin A was observed in 2.5-4 year old wines, although at this age malvidin 3-glucoside is already degraded to a large extent. This phenomenon is explained by the increased ratio of caffeic acid/malvidin 3-glucoside, which strongly favors the formation of pinotin A and makes side reactions less likely. Pinotin A formation proceeds as long as a certain level of malvidin 3-glucoside is maintained in the wines. In wines >5-6 years old degradation or polymerization of pinotin A finally exceeds the rate of its de novo synthesis.
Extracted Claims
6 claims extracted from this paper into the knowledge graph
2.5-4 year old wines show most rapid synthesis of pinotin A
“The most rapid synthesis of pinotin A was observed in 2.5-4 year old wines, although at this age malvidin 3-glucoside is already degraded to a large extent.”
aging increases concentration of pinotin A
“An exponential increase of the concentration of this aging product was observed with prolonged storage time.”
malvidin 3-glucoside and caffeic acid react to form pinotin A
“Pinotage red wines were found to contain a reaction product of malvidin 3-glucoside and caffeic acid, the so-called pinotin A.”