Extraction kinetics of anthocyanins from skin to pulp during carbonic maceration of winegrape berries with different ripeness levels

The evolution of the content and profile of anthocyanins was studied in the skin and pulp of Gamay winegrapes during twelve days of carbonic maceration. The ripening effect was also investigated using berries belonging to two density classes (A = 1094-1100 kg/m3 and B = 1107-1115 kg/m3). The ripest berries showed a higher extraction yield, even though the differences among density classes tended to decline towards the end of the process, and few significant differences were found in the anthocyanin profile. The maceration time influenced strongly not only the content and extraction yield, but also the qualitative composition of anthocyanins towards the predominance of malvidin derivatives. Finally, the extraction yield of anthocyanins was positively related with the ethanol formed and the skin mechanical properties using linear regression models, which showed that the skin hardness is likely to be an important variable in modelling daily anthocyanin extraction during carbonic maceration, particularly from the sixth day.