Copigmentation is a very important contributor to colour in young red wines. Further understanding of the copigmentation effect has been elucidated by investigating the contribution of various fractions of grapes - skin, pulp, and seed - in varieties Shiraz, Sangiovese and Pinot Noir. A series of spectrophotometric and HPLC experiments elucidated the effect of this interaction in grape extracts simulating wine conditions. A post-column reaction method was developed to permit the evaluation of the reactivity of each grape anthocyanin with different reagents: pure compounds (quercetin and caffeic acid) and extracts of grape sections (seed, Semillon skin, Semillon pulp). Certain extracts produced a decrease in colour, suggesting that competing equilibria are important in the copigmentation effect and that an "anti- copigmentation" effect is possible. Flavonols appear to be the best copigmentation cofactors, and the concentration of quercetin 3-O-glucoside was found to correlate with the strength of copigmentation. Flavonols appear capable of displacing cofactors derived from seed extracts.
Copigmentation and anti-copigmentation in grape extracts studied by spectrophotometry and post-column-reaction HPLC / L. Rustioni, D.R. Bedgood, O. Failla, P.D. Prenzler, K. Robards. - In: FOOD CHEMISTRY. - ISSN 0308-8146. - 132:4(2012), pp. 2194-2201. [10.1016/j.foodchem.2011.12.058]
Copigmentation and anti-copigmentation in grape extracts studied by spectrophotometry and post-column-reaction HPLC
L. Rustioni
;O. Failla;
2012
Abstract
Copigmentation is a very important contributor to colour in young red wines. Further understanding of the copigmentation effect has been elucidated by investigating the contribution of various fractions of grapes - skin, pulp, and seed - in varieties Shiraz, Sangiovese and Pinot Noir. A series of spectrophotometric and HPLC experiments elucidated the effect of this interaction in grape extracts simulating wine conditions. A post-column reaction method was developed to permit the evaluation of the reactivity of each grape anthocyanin with different reagents: pure compounds (quercetin and caffeic acid) and extracts of grape sections (seed, Semillon skin, Semillon pulp). Certain extracts produced a decrease in colour, suggesting that competing equilibria are important in the copigmentation effect and that an "anti- copigmentation" effect is possible. Flavonols appear to be the best copigmentation cofactors, and the concentration of quercetin 3-O-glucoside was found to correlate with the strength of copigmentation. Flavonols appear capable of displacing cofactors derived from seed extracts.File | Dimensione | Formato | |
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