Color of red wine

Rot-warmhkrte, /. (Metal.) red-hardness, -warmhitze, /. red heat, -wein, m. red wine, -weinfarbe, /. color of red wine, claret. 

PVPP is commonly used to remove undesirable brown or pink pigments from wine (Jackson, 1994). However, because much of the color of red wine is due to polyphenolic compounds, treatment with PVPP or other polyamides can diminish the red color and so must be carefully controlled. Additions of gelatin or egg white (egg albumin has about... 

Finally, we try to develop a chemical interpretation for the color of red wine—i.e., the specific role of different substances and the changes they undergo which cause the evolution of wine color, especially during aging. 

Properties of Anthocyanins. Several chemical or physicochemical properties of the anthocyanins influence their structure and consequently their coloration they are thus important in interpreting the color of red wine. 

Respective Roles of Anthocyanins and Tannins. The mediation of tannins and anthocyanins in the color of red wine, covered in our work (38) has been conducted in model solutions (17). The procedure is as follows. 

The non-flavonoid phenolic constituents in wine are divided into hydroxybenzoic acids and hydroxycinnamic acids, volatile phenols, stilbenes and miscellaneous compounds (e.g. lignans and coumarins). Although non-colored, the non-flavonoid constituents are known to enhance and stabilize the color of red wines by intra- and intermolecular reactions. They furthermore contribute to wine flavor (volatile phenolic acids) and some of them (e.g. resveratrol) exhibit potent biological activities. 

Darias-Martin, L, Martfn-Luis, B., CarrUlo-Lopez, M., Lamuela-Raventos, R., Diaz-Romero, C., Boulton, R. (2002). Effect of caffeic acid on the color of red wine. J. Agric. Food Chem., 50, 2062-2067. 

This latter methodology has hardly been used to evaluate the strength of the copigmentation effect, although it has been employed to characterise the color of red wines. 

Aldehydes also affect the aging characteristics and color stability of wines. Reactions with SOj decrease the amount of free SOj available to act as an antioxidant during wine storage. Acetaldehyde in particular can catalyze the condensation of flavonoids to form polymeric pigments which directly affect the taste and color of red wines (2). 

Changes in the color of red wines that occur during aging are due to the anthocyanins undergoing chemical reactions and polymerization with the other wine compounds. More than 100 structures belong to the pigment families of anthocyanins, pyranoanthocyanins, direct flava-nol-anthocyanin condensation products, and acetaldehyde-mediated... 

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