Comparison of chromatic properties, stability and antioxidant capacity of anthocyanin-based aqueous extracts from grape pomace obtained from different vinification methods

The chromatic properties of anthocyanin-based aqueous extracts obtained from grape pomace from different vinifications methods (one rosé vinification, 6 h of skin contact time and three red wine vinifications, with 4, 8 and 12 days of skin contact time) have been studied. Differences due to the vinification method from which the pomace was obtained were clearly observed. Extracts from rosé vinifications had the highest content of anthocyanin compounds (measured both spectrophotometrically and by HPLC methods) although the total phenol content did not differ significantly between the different pomace extracts. As regards the stability of the different aqueous extracts under different pH, temperature and light conditions, only small differences were observed. Also, the antioxidant capacity of the extracts was evaluated and no significant differences were found between them; a better correlation being found between antioxidant capacity and estimated total phenol content than with anthocyanin content.