A process is proposed to selectively extract polyphenols and anthocyanins from lyophilized grape residues. The compounds of interest are first extracted from the vegetable matter, using a tartaric buffer to avoid extract degradation due to polyphenol oxidase, hydrolysis or esterification and to eliminate part of the interfering compounds (mainly sugars). Then, they are selectively adsorbed on a C18 column and desorbed using methanol. The methanolic solution is processed by supercritical antisolvent extraction (SAE) at various process conditions. The optimized result is a powderous, solventless precipitate that, in the case of Cannonau cultivar, contains 33 polyphenols and 7 anthocyanins. The overall content of polyphenols recovered is of 521 mg/kg and the total content of anthocyanins is of 15542 mg/kg of treated material. The most abundant compounds extracted are cathechin (113.9 mg/kg), epicathechin (96.9 mg/kg), epicathechin gallate (101.6 mg/kg) for polyphenols and malvin acetate (1304 mg/kg) and malvin cumarate (9256.9 mg/kg) for anthocyanins. SAE processing confirms to be very effective in producing solventless selective extracts, avoiding their degradation. (C) 2010 Elsevier B.V. All rights reserved.
Antioxidant compounds recovery from grape residues by a supercritical antisolvent assisted process
FILIPPINO, GIORGIA;
2010-01-01
Abstract
A process is proposed to selectively extract polyphenols and anthocyanins from lyophilized grape residues. The compounds of interest are first extracted from the vegetable matter, using a tartaric buffer to avoid extract degradation due to polyphenol oxidase, hydrolysis or esterification and to eliminate part of the interfering compounds (mainly sugars). Then, they are selectively adsorbed on a C18 column and desorbed using methanol. The methanolic solution is processed by supercritical antisolvent extraction (SAE) at various process conditions. The optimized result is a powderous, solventless precipitate that, in the case of Cannonau cultivar, contains 33 polyphenols and 7 anthocyanins. The overall content of polyphenols recovered is of 521 mg/kg and the total content of anthocyanins is of 15542 mg/kg of treated material. The most abundant compounds extracted are cathechin (113.9 mg/kg), epicathechin (96.9 mg/kg), epicathechin gallate (101.6 mg/kg) for polyphenols and malvin acetate (1304 mg/kg) and malvin cumarate (9256.9 mg/kg) for anthocyanins. SAE processing confirms to be very effective in producing solventless selective extracts, avoiding their degradation. (C) 2010 Elsevier B.V. All rights reserved.
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