Hydroxycinnamic tartaric acid,

Synthesis of caffeic and ferulic acids also needs hydroxylase and methyltransferase enzymes transformation into hydroxycinnamic tartaric acid esters (HCTA) is operated by an acyltransferase enzyme. The scheme shown in Figure 2.9 summarizes the biosynthetic pathways described. 

Figure 2.13 Fractionation of cinnamic acids in must and wine using two C18 cartridges (Di Stefano and Cravero, 1992). HCA hydroxycinnamic acids HCTA hydroxycinnamic tartaric acid esters GRP 2-S-glutathionyl caffeyl tartaric acid...

Advances in analytical procedures resulted in several reports on anthocyanins acy-lated with hydroxycinnamic acids (p-coumaric, caffeic, ferulic, sinapic, and 3,5-dihydroxycinnamic acids), hydroxybenzoic acids (p-hydroxybenzoic and gallic acids), and aliphatic acids (malonic, acetic, malic, oxalic, succinic and tartaric acids). However, not all of them were found in anthocyanins isolated from foods. Among the 44 fruits listed in Table 4.3.1, 15 presented acylated anthocyanins as did 12 of 13 vegetables shown in Table 4.3.3 and 2 of the 9 grains cited in Table 4.3.4. On the other hand, acylated anthocyanins were found in all grapes from Vitis species, although at different abundance levels, as can be seen in Table 4.3.2. A higher... 

For white wines (85), a similar HPLC condition to that of Betes-Saura et al. (79) was employed with a Nucleosil C)8 column (250 X 4.0-mm ID, 5 /zm) with binary gradient using eluent (A) acidified water (pH 2.65) and eluent (B) 20% A with 80% acetonitrile applied for hydroxy-cinnamate derivatives esters (caffeoyl tartaric, p-coumaroyl tartaric, and feruloyl tartaric acid esters) and free hydroxycinnamic acids (caffeic, ferulic, and p-coumaric acids). 

Ong, B. Y. Nagel, C. W. Hydroxycinnamic Acid-Tartaric Acid Ester Content in... 

Hydroxycinnamic Acid-Tartaric Acid Ester Content of the Musts and Grape Varieties Grown in the Pacific Northwest, Am. J. Enol. Vitic. 1979, 30, 198-201. 

Romeyer, F., Macheix, J., Goiffon, J., Reminiac, C., Sapis, J. C. (1983). The browning capacity of grapes. 3. Changes and importance of hydroxycinnamic add-tartaric acid esters during development and maturation of the fruit. J. Agric. Food Chem., 31, 346-349. 

Grapes contain several hydroxycinnamic acids, p-coumaric, caffeic, ferulic and sinapic acids, which exist as free acids and esterified with tartaric acid. Saccha-romyces species can take up free acids to produce the corresponding vinyl phenol catalysed by hydroxycinnamate decarboxylase (phenylacrylic acid decarboxylase Padlp) (Fig 8D.11) (Chatonnet et al. 1992b Chatonnet et al. 1993 Edlin et al. 1995). Vinyl phenols are unstable and highly reactive. Dekkera bruxellensis is one of few wine microorganisms that can further reduce vinyl phenols to highly stable ethyl phenols in wine. Vinyl phenols can also react with anthocyanins to form vinyl derivatives, a reaction that is favoured by fermentation yeast having hydroxycinnamate decarboxylase activity (Morata et al. 2006). 

Hydroxycinnamic acids possess a C6-C3 skeleton and formally belong to the group of phenylpropanoids. The different compounds present in wine are mainly derived from the hydroxycinnamic acids caffeic acid, p-coumaric acid, ferulic acid, and sinapic acid (Fig. 9C.2). These derivatives can be present in cis- and trans-configured forms, while the trans forms are more stable and therefore more prevalent. In wine HCA are present in low amounts in their free form, while the depside forms, i.e. esters of l-(-i-)-tartaric acid, are predominant. The ubiquitous chlorogenic acids, esters of HCA and quinic acid, cannot be found in wine but are replaced by the tartaric acid esters instead (Ong and Nagel 1978 Singleton et al. 1978 Somers etal. 1987). 

Ong, B. Y., Nagel, C. W. (1978). High-Pressure Liquid-Chromatographic analysis of hydroxycinnamic acid - tartaric acid esters and their glucose esters in Vitis vinifera. J. Chro-... 

Figure 2.2 Hydroxycinnamoyl tartaric acid (CTA, p-CuTA, FTA) esters in grape and the correspondent hydroxycinnamic acids (HCA) found in wine...

Finally, oxidation of hydroxycinnamoyl tartaric acid (HCTA) into hydroxycinnamic acids (HCA), and the successive decarboxylation operated by Saccharomyces yeasts, or reduction and decarboxylation by Brettanomyces yeasts, induce off-flavours due to vinyl phenols and ethyl phenols formation, respectively. 

Ong, B.Y. and Nagel, C.W. (1978) High-pressure liquid chromatographic analysis of hydroxycinnamic acid-tartaric acid esters and their clucose esters in Vitis Vinifera, J. Chromatogr., 157, 345-355. 

FIGURE 10.4 Tartaric acid esters of several hydroxycinnamic acids. 

Components The shoots contain large amounts of silicic acid in the cell walls (up to 8%). The fatty acids found in H. t. contain 23-30 C-atoms. Secondary constituents of Equisetum species include alkaloids (e.g., palustrine), numerous flavones (e.g., 6-chlo-roapigenin), and flavonols as well as their dihydro derivatives, phenol- and hydroxycinnamic acids (e.g., 2,3-0-di-( )-caffeoyl-mew-tartaric acid in E. ar-vense), indanone derivatives and novel styrylpyrones such as, e.g., equisetumpyrone. The secondary product pattern reveals interspecific and intraspecific differences whereby the latter depend on the state of development. ... 

As regards hydroxycinnamic acids, they absorb at two regions of the UV spectrum, presenting a maximum at 225—235 nm and two other, very near of each other, by 290-330 nm. The double absorption in this region arises from the presence of cis and tram isomers, and the ratio between these two forms contributes to the final spectrum. In alkaline medium, aU three maxima suffer a bath-ochromic shift. The different esters of the same acid present similar spectrum, regardless of the molecule presenting the alcohol function (quinic acid, sugar, or tartaric acid). ° ... 

The hydroxycinnamic acids, with a Cg-Cj skeleton, are represented by six common cinnamic acids. All plants are thought to contain at least three of them. Hydroxycinnamic acids are commonly presented in plants as esters of quinic acid, shikimic acid, and tartaric acid. For instance, chlorogenic acid is an ester of caffeic acid and quinic acid (Vermerris and Nicholson, 2008). 

Interactions between LAB and phenolic compounds are very complicated. Among them, the decarboxylation of hydroxycinnamic acids (caffeic, p-coumaric, and ferulic) is of particular interest in oenology (Silva et al. 2011). These acids are esterified to tartaric acid and freed by the cinnamoyl esterase by yeasts and less often by bacteria. The decarboxylation releases vinyl phenols, which are reduced to ethyl phenols producing off-flavors. The second reaction can be achieved by bacteria to maintain the redox balance however, it is mainly carried out by the spoilage yeast Brettanomyces bruxellensis, often present in wine. 

Phenolic acids are rarely present as free forms, except in processed food, but occur more frequently as soluble or insoluble esters. These esters are formed with polysaccharides or simple sugars, with quinic acid or other carboxylic acids such as tartaric or shikimic acids [Herrmann, 1989], with other phenolic acids, with lipids [Clifford, 2000], with sterols or glycerol [Clifford, 1999], or with amino acids [Clifford and Knight, 2004], To quinic acid, they can be conjugated as mono-, di-, tri-, and tetra-esters [Clifford, 2000]. The multiple esters can contain the same or different hydroxycinnamic acids. Among the hydroxycinnamic conjugates, caffeoylquinic and di-caffeoylquinic acids... 

Among the hydroxycinnamic acids, caftaric acid predominates (up to 50% of total hydroxycinnamic acids). Other important substances are the tartaric esters of p-coumaric acid and ferulic acid, and the franx-p-coumaric glucoside (Somers et al. 1987). The concentration levels of hydroxycinnamic acid derivatives in wine depend on many factors like grape variety, growing conditions, climate, etc. It is... 

In grapes or grape juices, the tartaric esters may be hydrolysed by enzymes from contaminant fungi or from commercial pectolytic preparations, both with cin-namoyl decarboxilase activity, releasing free hydroxycinnamic acid forms (Dugelay et al. 1993 Gerbaux et al. 2002). However, the tartaric esters are mostly hydrolysed after malolactic fermentation (Hernandez et al. 2006, 2007), it being hypothesised that the hydrolytic activity of lactic acid bacteria follows the completion of malic conversion to lactic acid (Cabrita et al. 2007) (see Table 11.4). 

Hydroxycinnamics are the third most abundant group of phenolic compounds in grapes and mainly comprise caffeic, coumaric, ferulic acids, and their corresponding tartaric esters (Fig. 83.2e). The hydroxycinnamic esters are more concentrated (2- to 100-fold) in grape skin than in pulp. Differences in total amount and proportion have been repotted according to grape varieties [32]. 

Hydroxycinnamic acids are found mainly in skin and, to a lesser extent, in leaves [101,102] and stems [97]. The most abundant acids (viz., caffeic, p-coumaric, and feralic) are present as tartaric esters (caftaric, cutaric, and fertaric acids Figure 4.7) or in acylated anthocyanins (basically, p-coumaric and caffeic acids). 

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