Caffeoyltartaric acid

Anthocyanin reaction products Caffeoyltartaric acid-malvidin 3-0-glc adducts (e.g., 5 1, Figure 5.4)... 

Caffeoyltartaric acid-anthocyanin adduct (hemiketal form)... 

FIGURE 5.S Anthocyanin reactions with caffeoyltartaric acid o-quinone coupled oxidation of cyanidin 3-glucoside (A) and nucleophilic addition of anthocyanins (B). Anthocyanin-caffeoyltartaric acid adducts are represented as one of the possible isomers, namely 2-(8-anthocyanin) caffeoyltartaric acid (5 1). 

Finally, reactions of flavonoid and nonflavonoid precursors are affected by other parameters like pH, temperature, presence of metal catalysts, etc. In particular, pH values determine the relative nucleophilic and electrophilic characters of both anthocyanins and flavanols. Studies performed in model solutions showed that acetaldehyde-mediated condensation is faster at pH 2.2 than at pH 4 and limited by the rate of aldehyde protonation. The formation of flavanol-anthocyanin adducts was also limited by the rate of proanthocyanidin cleavage, which was shown to take place at pH 3.2, but not at pH 3.8. Nucleophilic addition of anthocyanins was faster at pH 3.4 than at pH 1.7, but still took place at pH values much lower than those encountered in wine, as evidenced by the formation of anthocyanin-caffeoyltartaric acid adducts, methylmethine anthocyanin-flavanol adducts,and flavanol-anthocyanin adducts. The formation of pyranoanthocyanins requiring the flavylium cation was faster under more acidic conditions, as expected, but took place in the whole wine pH range. Thus, the availability of either the flavylium or the hemiketal form does not seem to limit any of the anthocyanin reactions. 

Cheynier, V., Basire, N., and Rigaud, J. (1989). Mechanism of trans-caffeoyltartaric acid and catechin oxidation in model solutions containing grape polyphenoloxidase. /. Agric. Food Chem. 37,1069-1071. 

All natural anthocyanins suffer from inherent instability, so they may be degraded to form colorless or brown-colored, often insoluble products. It is evident, that depending on the reaction type, different degradation products are formed however, only little analytical data is available. For example, after reaction of anthocyanins with hydrogen peroxide, substances of the benzofu-ran type were detected (139). Studies with grape must like model solutions indicated that anthocyanins are degraded by coupled oxidation and that they form adducts with caffeoyltartaric acid... 

Tartaric acid Feruloyl (i.e., ferulic acid) 2,3-O-dicaffeoyltartaric acid (Cichoric Acid) R1, R2 = X 2-0-caffeoyl-3-0-feruloyltartaric acid R1 = X, R2 = Y 2-O-caffeoyltartaric acid (Caftaric acid) R1 = X, R2= H... 

Among the phenolic acid derivatives, the most abundant and characteristic is caffeoyltartaric acid. p-Coumaroyl tartaric and... 

Fig. (8). HPLC chromatogram of red lettuce anthocyanins and other phenols (1) caffeoyltartaric acid, (2) chlorogenic acid, (3) dicaffeoyltartaric acid, (4) quercetin 7-glucoside 3-(6 -malonylglucoside), (5) dicaffeoylquinic acid dsochlorogenic acid), (6) quercetin 3-glucuronido, (7) quercetin 3-glucosido, (8) quercetin 3-malonylglucoside, and (9) cyanidin 3-malonylglucoside. HPLC conditions RP Cjg column (12 x 0.4 cm particle size 5 pm). Mobile phase acidified water (5% formic acid) (A) and methanol (B). Gradient 0 min- 5% B, 25 min- 40% B. Flow rate I mL/min.

Mono (3,4-dihydroxycinnamoyl) Mono-caffeoyltartaric acid. Caftaric add. Caffeoyltartaric acid [67879-58-7]... 

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